diff --git a/main.go b/main.go
index 4d20b6e..4dbfb1c 100644
--- a/main.go
+++ b/main.go
@@ -152,12 +152,12 @@ func screen(computer *okean240.ComputerType, raster *canvas.Raster, label *widge
 	}
 }
 
-const ticksPerTicker = 3
+const ticksPerTicker uint64 = 3
 
 func emulator(computer *okean240.ComputerType) {
 	ticker := time.NewTicker(66 * time.Nanosecond)
-	var ticks = 0
-	var nextClock = ticks + ticksPerTicker
+	var ticks uint64 = 0
+	var nextClock uint64 = ticks + ticksPerTicker
 	//var ticksCPU = 3
 	for range ticker.C {
 		//for {
diff --git a/okean240/computer.go b/okean240/computer.go
index 688b09a..ae62f34 100644
--- a/okean240/computer.go
+++ b/okean240/computer.go
@@ -8,14 +8,14 @@ import (
 	"okemu/okean240/pic"
 	"okemu/okean240/pit"
 	"okemu/okean240/usart"
-	"okemu/z80em"
+	"okemu/z80/js"
 
 	"fyne.io/fyne/v2"
 	log "github.com/sirupsen/logrus"
 )
 
 type ComputerType struct {
-	cpu           *z80em.Z80Type
+	cpu           *js.Z80
 	memory        Memory
 	ioPorts       [256]byte
 	cycles        uint64
@@ -73,7 +73,7 @@ func New(cfg *config.OkEmuConfig) *ComputerType {
 	c.memory = Memory{}
 	c.memory.Init(cfg.MonitorFile, cfg.CPMFile)
 
-	c.cpu = z80em.New(&c)
+	c.cpu = js.New(&c)
 
 	c.cycles = 0
 	c.dd17EnableOut = false
@@ -109,17 +109,17 @@ func (c *ComputerType) Reset() {
 
 }
 
-func (c *ComputerType) Do() int {
+func (c *ComputerType) Do() uint64 {
 	//s := c.cpu.GetState()
 	//if s.PC == 0xe0db {
 	//	log.Debugf("breakpoint")
 	//}
-	ticks := uint64(c.cpu.RunInstruction())
+	ticks := c.cpu.RunInstruction()
 	c.cycles += ticks
 	//if c.cpu.PC == 0xFF26 {
 	//	log.Debugf("%4X: H:%X L:%X A:%X B: %X C: %X D: %X E: %X", c.cpu.PC, c.cpu.H, c.cpu.L, c.cpu.A, c.cpu.B, c.cpu.C, c.cpu.D, c.cpu.E)
 	//}
-	return int(ticks)
+	return ticks
 }
 
 func (c *ComputerType) GetPixel(x uint16, y uint16) color.RGBA {
diff --git a/z80/constants.go b/z80/c99/constants.go
similarity index 99%
rename from z80/constants.go
rename to z80/c99/constants.go
index 922d7be..8f10c32 100644
--- a/z80/constants.go
+++ b/z80/c99/constants.go
@@ -1,4 +1,4 @@
-package z80
+package c99
 
 var cyc_00 = [256]byte{
 	4, 10, 7, 6, 4, 4, 7, 4, 4, 11, 7, 6, 4, 4, 7, 4,
diff --git a/z80/c99/cpu.go b/z80/c99/cpu.go
new file mode 100644
index 0000000..de65756
--- /dev/null
+++ b/z80/c99/cpu.go
@@ -0,0 +1,191 @@
+package c99
+
+import "okemu/z80"
+
+type MemIoRW interface {
+	// M1MemRead Read byte from memory for specified address @ M1 cycle
+	M1MemRead(addr uint16) byte
+	// MemRead Read byte from memory for specified address
+	MemRead(addr uint16) byte
+	// MemWrite Write byte to memory to specified address
+	MemWrite(addr uint16, val byte)
+	// IORead Read byte from specified port
+	IORead(port uint16) byte
+	// IOWrite Write byte to specified port
+	IOWrite(port uint16, val byte)
+}
+
+type CPUInterface interface {
+	// Reset CPU to initial state
+	Reset()
+	// RunInstruction Run single instruction, return number of CPU cycles
+	RunInstruction() byte
+	// GetState Get current CPU state
+	GetState() *Z80
+	// SetState Set current CPU state
+	SetState(state *Z80)
+}
+
+type Z80 struct {
+
+	// cycle count (t-states)
+	cyc      uint64
+	inst_cyc byte
+
+	// special purpose registers
+	pc, sp, ix, iy uint16
+
+	// "wz" register
+	mem_ptr uint16
+
+	// main registers
+	a, b, c, d, e, h, l byte
+
+	// alternate registers
+	a_, b_, c_, d_, e_, h_, l_, f_ byte
+
+	// interrupt vector, memory refresh
+	i, r byte
+
+	// flags: sign, zero, yf, half-carry, xf, parity/overflow, negative, carry
+	sf, zf, yf, hf, xf, pf, nf, cf bool
+	iff_delay                      byte
+	interrupt_mode                 byte
+	int_data                       byte
+	iff1                           bool
+	iff2                           bool
+	halted                         bool
+	int_pending                    bool
+	nmi_pending                    bool
+
+	core MemIoRW
+}
+
+// New initializes a Z80 instance and return pointer to it
+func New(core MemIoRW) *Z80 {
+	z := Z80{}
+	z.core = core
+
+	z.cyc = 0
+
+	z.pc = 0
+	z.sp = 0xFFFF
+	z.ix = 0
+	z.iy = 0
+	z.mem_ptr = 0
+
+	// af and sp are set to 0xFFFF after reset,
+	// and the other values are undefined (z80-documented)
+	z.a = 0xFF
+	z.b = 0
+	z.c = 0
+	z.d = 0
+	z.e = 0
+	z.h = 0
+	z.l = 0
+
+	z.a_ = 0
+	z.b_ = 0
+	z.c_ = 0
+	z.d_ = 0
+	z.e_ = 0
+	z.h_ = 0
+	z.l_ = 0
+	z.f_ = 0
+
+	z.i = 0
+	z.r = 0
+
+	z.sf = true
+	z.zf = true
+	z.yf = true
+	z.hf = true
+	z.xf = true
+	z.pf = true
+	z.nf = true
+	z.cf = true
+
+	z.iff_delay = 0
+	z.interrupt_mode = 0
+	z.iff1 = false
+	z.iff2 = false
+	z.halted = false
+	z.int_pending = false
+	z.nmi_pending = false
+	z.int_data = 0
+	return &z
+}
+
+// RunInstruction executes the next instruction in memory + handles interrupts
+func (z *Z80) RunInstruction() uint64 {
+	pre := z.cyc
+	if z.halted {
+		z.exec_opcode(0x00)
+	} else {
+		opcode := z.nextb()
+		z.exec_opcode(opcode)
+	}
+	z.process_interrupts()
+	return z.cyc - pre
+}
+
+func (z *Z80) GetState() *z80.Z80CPU {
+	return &z80.Z80CPU{
+		A:                 z.a,
+		B:                 z.b,
+		C:                 z.c,
+		D:                 z.d,
+		E:                 z.e,
+		H:                 z.h,
+		L:                 z.l,
+		AAlt:              z.a_,
+		BAlt:              z.b_,
+		CAlt:              z.c_,
+		DAlt:              z.d_,
+		EAlt:              z.e_,
+		HAlt:              z.h_,
+		LAlt:              z.l_,
+		IX:                z.ix,
+		IY:                z.iy,
+		I:                 z.i,
+		R:                 z.r,
+		SP:                z.sp,
+		PC:                z.pc,
+		Flags:             z.getFlags(),
+		FlagsAlt:          z.getAltFlags(),
+		IMode:             z.interrupt_mode,
+		Iff1:              z.iff1,
+		Iff2:              z.iff2,
+		Halted:            z.halted,
+		DoDelayedDI:       z.int_pending,
+		DoDelayedEI:       z.int_pending,
+		CycleCounter:      z.inst_cyc,
+		InterruptOccurred: false,
+	}
+}
+
+func (z *Z80) getFlags() z80.FlagsType {
+	return z80.FlagsType{
+		S: z.sf,
+		Z: z.zf,
+		Y: z.yf,
+		H: z.hf,
+		X: z.xf,
+		P: z.pf,
+		N: z.nf,
+		C: z.cf,
+	}
+}
+
+func (z *Z80) getAltFlags() z80.FlagsType {
+	return z80.FlagsType{
+		S: z.f_&0x80 != 0,
+		Z: z.f_&0x40 != 0,
+		Y: z.f_&0x20 != 0,
+		H: z.f_&0x10 != 0,
+		X: z.f_&0x08 != 0,
+		P: z.f_&0x04 != 0,
+		N: z.f_&0x02 != 0,
+		C: z.f_&0x01 != 0,
+	}
+}
diff --git a/z80/helper.go b/z80/c99/helper.go
similarity index 98%
rename from z80/helper.go
rename to z80/c99/helper.go
index f21ca5d..6cf3020 100644
--- a/z80/helper.go
+++ b/z80/c99/helper.go
@@ -1,4 +1,4 @@
-package z80
+package c99
 
 import log "github.com/sirupsen/logrus"
 
@@ -155,7 +155,7 @@ func (z *Z80) updateXY(result byte) {
 	z.xf = result&0x08 != 0
 }
 
-func (z *Z80) debug_output() {
+func (z *Z80) debugOutput() {
 	log.Debugf("PC: %04X, AF: %04X, BC: %04X, DE: %04X, HL: %04X, SP: %04X, IX: %04X, IY: %04X, I: %02X, R: %02X",
 		z.pc, (uint16(z.a)<<8)|uint16(z.get_f()), z.get_bc(), z.get_de(), z.get_hl(), z.sp,
 		z.ix, z.iy, z.i, z.r)
diff --git a/z80/opcodes.go b/z80/c99/opcodes.go
similarity index 99%
rename from z80/opcodes.go
rename to z80/c99/opcodes.go
index 4f1cbce..379f196 100644
--- a/z80/opcodes.go
+++ b/z80/c99/opcodes.go
@@ -1,4 +1,4 @@
-package z80
+package c99
 
 import log "github.com/sirupsen/logrus"
 
diff --git a/z80/opcodesCB.go b/z80/c99/opcodesCB.go
similarity index 99%
rename from z80/opcodesCB.go
rename to z80/c99/opcodesCB.go
index d2c6ad4..6cf3180 100644
--- a/z80/opcodesCB.go
+++ b/z80/c99/opcodesCB.go
@@ -1,4 +1,4 @@
-package z80
+package c99
 
 import log "github.com/sirupsen/logrus"
 
diff --git a/z80/opcodesDDFD.go b/z80/c99/opcodesDDFD.go
similarity index 99%
rename from z80/opcodesDDFD.go
rename to z80/c99/opcodesDDFD.go
index 6d74423..77bea54 100644
--- a/z80/opcodesDDFD.go
+++ b/z80/c99/opcodesDDFD.go
@@ -1,4 +1,4 @@
-package z80
+package c99
 
 // executes a DD/FD opcode (IZ = IX or IY)
 func (z *Z80) exec_opcode_ddfd(opcode byte, iz *uint16) {
diff --git a/z80/opcodesED.go b/z80/c99/opcodesED.go
similarity index 99%
rename from z80/opcodesED.go
rename to z80/c99/opcodesED.go
index e323949..27991a7 100644
--- a/z80/opcodesED.go
+++ b/z80/c99/opcodesED.go
@@ -1,4 +1,4 @@
-package z80
+package c99
 
 import log "github.com/sirupsen/logrus"
 
diff --git a/z80/cpu.go b/z80/cpu.go
index e31f028..99e771d 100644
--- a/z80/cpu.go
+++ b/z80/cpu.go
@@ -17,158 +17,56 @@ type CPUInterface interface {
 	// Reset CPU to initial state
 	Reset()
 	// RunInstruction Run single instruction, return number of CPU cycles
-	RunInstruction() byte
+	RunInstruction() uint64
 	// GetState Get current CPU state
-	GetState() *Z80
+	GetState() *Z80CPU
 	// SetState Set current CPU state
-	SetState(state *Z80)
+	SetState(state *Z80CPU)
 }
 
-type Z80 struct {
-
-	// cycle count (t-states)
-	cyc uint64
-
-	// special purpose registers
-	pc, sp, ix, iy uint16
-
-	// "wz" register
-	mem_ptr uint16
-
-	// main registers
-	a, b, c, d, e, h, l byte
-
-	// alternate registers
-	a_, b_, c_, d_, e_, h_, l_, f_ byte
-
-	// interrupt vector, memory refresh
-	i, r byte
-
-	// flags: sign, zero, yf, half-carry, xf, parity/overflow, negative, carry
-	sf, zf, yf, hf, xf, pf, nf, cf bool
-	iff_delay                      byte
-	interrupt_mode                 byte
-	int_data                       byte
-	iff1                           bool
-	iff2                           bool
-	halted                         bool
-	int_pending                    bool
-	nmi_pending                    bool
-
-	core MemIoRW
+// FlagsType - Processor flags
+type FlagsType struct {
+	S bool
+	Z bool
+	Y bool
+	H bool
+	X bool
+	P bool
+	N bool
+	C bool
 }
 
-// New initializes a Z80 instance and return pointer to it
-func New(core MemIoRW) *Z80 {
-	z := Z80{}
-	z.core = core
-
-	z.cyc = 0
-
-	z.pc = 0
-	z.sp = 0xFFFF
-	z.ix = 0
-	z.iy = 0
-	z.mem_ptr = 0
-
-	// af and sp are set to 0xFFFF after reset,
-	// and the other values are undefined (z80-documented)
-	z.a = 0xFF
-	z.b = 0
-	z.c = 0
-	z.d = 0
-	z.e = 0
-	z.h = 0
-	z.l = 0
-
-	z.a_ = 0
-	z.b_ = 0
-	z.c_ = 0
-	z.d_ = 0
-	z.e_ = 0
-	z.h_ = 0
-	z.l_ = 0
-	z.f_ = 0
-
-	z.i = 0
-	z.r = 0
-
-	z.sf = true
-	z.zf = true
-	z.yf = true
-	z.hf = true
-	z.xf = true
-	z.pf = true
-	z.nf = true
-	z.cf = true
-
-	z.iff_delay = 0
-	z.interrupt_mode = 0
-	z.iff1 = false
-	z.iff2 = false
-	z.halted = false
-	z.int_pending = false
-	z.nmi_pending = false
-	z.int_data = 0
-	return &z
-}
-
-// RunInstruction executes the next instruction in memory + handles interrupts
-func (z *Z80) RunInstruction() {
-	if z.halted {
-		z.exec_opcode(0x00)
-	} else {
-		opcode := z.nextb()
-		z.exec_opcode(opcode)
-	}
-	z.process_interrupts()
-}
-
-func (z *Z80) GetState() *Z80 {
-	return &Z80{
-		cyc:     z.cyc,
-		pc:      z.pc,
-		sp:      z.sp,
-		ix:      z.ix,
-		iy:      z.iy,
-		mem_ptr: z.mem_ptr,
-
-		a:  z.a,
-		b:  z.b,
-		c:  z.c,
-		d:  z.d,
-		e:  z.e,
-		h:  z.h,
-		l:  z.l,
-		a_: z.a_,
-		b_: z.b_,
-		c_: z.c_,
-		d_: z.d_,
-		e_: z.e_,
-		h_: z.h_,
-		l_: z.l_,
-		f_: z.f_,
-
-		i: z.i,
-		r: z.r,
-
-		sf: z.sf,
-		zf: z.zf,
-		yf: z.yf,
-		hf: z.hf,
-		xf: z.xf,
-		pf: z.pf,
-		nf: z.nf,
-		cf: z.cf,
-
-		iff1: z.iff1,
-		iff2: z.iff2,
-
-		iff_delay:      z.iff_delay,
-		interrupt_mode: z.interrupt_mode,
-		halted:         z.halted,
-		int_pending:    z.int_pending,
-		nmi_pending:    z.nmi_pending,
-		core:           z.core,
-	}
+// Z80CPU - Processor state
+type Z80CPU struct {
+	A                 byte
+	B                 byte
+	C                 byte
+	D                 byte
+	E                 byte
+	H                 byte
+	L                 byte
+	AAlt              byte
+	BAlt              byte
+	CAlt              byte
+	DAlt              byte
+	EAlt              byte
+	HAlt              byte
+	LAlt              byte
+	IX                uint16
+	IY                uint16
+	I                 byte
+	R                 byte
+	SP                uint16
+	PC                uint16
+	Flags             FlagsType
+	FlagsAlt          FlagsType
+	IMode             byte
+	Iff1              bool
+	Iff2              bool
+	Halted            bool
+	DoDelayedDI       bool
+	DoDelayedEI       bool
+	CycleCounter      byte
+	InterruptOccurred bool
+	//core              MemIoRW
 }
diff --git a/z80em/constants.go b/z80/js/constants.go
similarity index 99%
rename from z80em/constants.go
rename to z80/js/constants.go
index fe99814..b9ce480 100644
--- a/z80em/constants.go
+++ b/z80/js/constants.go
@@ -1,4 +1,4 @@
-package z80em
+package js
 
 const OpHalt = 0x76
 const OpLdBB = 0x40
diff --git a/z80em/z80em.go b/z80/js/cpu.go
similarity index 75%
rename from z80em/z80em.go
rename to z80/js/cpu.go
index 6104b0a..5e30c69 100644
--- a/z80em/z80em.go
+++ b/z80/js/cpu.go
@@ -1,81 +1,19 @@
-package z80em
+package js
 
-import "fmt"
+import (
+	"fmt"
+	"okemu/z80"
 
-//const SpDefault uint16 = 0xffff
+	log "github.com/sirupsen/logrus"
+)
 
-// FlagsType - Processor flags
-type FlagsType struct {
-	S bool
-	Z bool
-	Y bool
-	H bool
-	X bool
-	P bool
-	N bool
-	C bool
+// const SpDefault uint16 = 0xffff
+type Z80 struct {
+	z80.Z80CPU
+	core z80.MemIoRW
 }
 
-// Z80Type - Processor state
-type Z80Type struct {
-	A                 byte
-	B                 byte
-	C                 byte
-	D                 byte
-	E                 byte
-	H                 byte
-	L                 byte
-	AAlt              byte
-	BAlt              byte
-	CAlt              byte
-	DAlt              byte
-	EAlt              byte
-	HAlt              byte
-	LAlt              byte
-	IX                uint16
-	IY                uint16
-	I                 byte
-	R                 byte
-	SP                uint16
-	PC                uint16
-	Flags             FlagsType
-	FlagsAlt          FlagsType
-	IMode             byte
-	Iff1              byte
-	Iff2              byte
-	Halted            bool
-	DoDelayedDI       bool
-	DoDelayedEI       bool
-	CycleCounter      byte
-	interruptOccurred bool
-	core              MemIoRW
-}
-
-type MemIoRW interface {
-	// M1MemRead Read byte from memory for specified address @ M1 cycle
-	M1MemRead(addr uint16) byte
-	// MemRead Read byte from memory for specified address
-	MemRead(addr uint16) byte
-	// MemWrite Write byte to memory to specified address
-	MemWrite(addr uint16, val byte)
-	// IORead Read byte from specified port
-	IORead(port uint16) byte
-	// IOWrite Write byte to specified port
-	IOWrite(port uint16, val byte)
-}
-
-type CPUInterface interface {
-	// Reset CPU to initial state
-	Reset()
-	// RunInstruction Run single instruction, return number of CPU cycles
-	RunInstruction() byte
-	// GetState Get current CPU state
-	GetState() *Z80Type
-	// SetState Set current CPU state
-	SetState(state *Z80Type)
-}
-
-func (z *Z80Type) Reset() {
+func (z *Z80) Reset() {
 	z.A = 0
 	z.R = 0
 	z.SP = 0xff
@@ -83,9 +21,9 @@ func (z *Z80Type) Reset() {
 	z.setFlagsRegister(0xff)
 	// Interrupts disabled
 	z.IMode = 0
-	z.Iff1 = 0
-	z.Iff2 = 0
-	z.interruptOccurred = false
+	z.Iff1 = false
+	z.Iff2 = false
+	z.InterruptOccurred = false
 
 	// Start not halted
 	z.Halted = false
@@ -96,8 +34,8 @@ func (z *Z80Type) Reset() {
 	fmt.Println("CPUInterface State Reset")
 }
 
-func (z *Z80Type) GetState() *Z80Type {
-	return &Z80Type{
+func (z *Z80) GetState() *z80.Z80CPU {
+	return &z80.Z80CPU{
 		A:            z.A,
 		B:            z.B,
 		C:            z.C,
@@ -128,7 +66,7 @@ func (z *Z80Type) GetState() *Z80Type {
 	}
 }
 
-func (z *Z80Type) SetState(state *Z80Type) {
+func (z *Z80) SetState(state *Z80) {
 	z.A = state.A
 	z.B = state.B
 	z.C = state.C
@@ -160,43 +98,45 @@ func (z *Z80Type) SetState(state *Z80Type) {
 }
 
 // New Create new
-func New(memIoRW MemIoRW) *Z80Type {
-	return &Z80Type{
-		A:    0,
-		B:    0,
-		C:    0,
-		D:    0,
-		E:    0,
-		H:    0,
-		L:    0,
-		AAlt: 0,
-		BAlt: 0,
-		CAlt: 0,
-		DAlt: 0,
-		EAlt: 0,
-		HAlt: 0,
-		IX:   0,
-		IY:   0,
-		I:    0,
+func New(memIoRW z80.MemIoRW) *Z80 {
+	return &Z80{
+		Z80CPU: z80.Z80CPU{
+			A:    0,
+			B:    0,
+			C:    0,
+			D:    0,
+			E:    0,
+			H:    0,
+			L:    0,
+			AAlt: 0,
+			BAlt: 0,
+			CAlt: 0,
+			DAlt: 0,
+			EAlt: 0,
+			HAlt: 0,
+			IX:   0,
+			IY:   0,
+			I:    0,
 
-		R:                 0,
-		SP:                0xffff,
-		PC:                0,
-		Flags:             FlagsType{true, true, true, true, true, true, true, true},
-		FlagsAlt:          FlagsType{true, true, true, true, true, true, true, true},
-		IMode:             0,
-		Iff1:              0,
-		Iff2:              0,
-		Halted:            false,
-		DoDelayedDI:       false,
-		DoDelayedEI:       false,
-		CycleCounter:      0,
-		interruptOccurred: false,
-		core:              memIoRW,
+			R:                 0,
+			SP:                0xffff,
+			PC:                0,
+			Flags:             z80.FlagsType{S: true, Z: true, Y: true, H: true, X: true, P: true, N: true, C: true},
+			FlagsAlt:          z80.FlagsType{S: true, Z: true, Y: true, H: true, X: true, P: true, N: true, C: true},
+			IMode:             0,
+			Iff1:              false,
+			Iff2:              false,
+			Halted:            false,
+			DoDelayedDI:       false,
+			DoDelayedEI:       false,
+			CycleCounter:      0,
+			InterruptOccurred: false,
+		},
+		core: memIoRW,
 	}
 }
 
-func (z *Z80Type) RunInstruction() byte {
+func (z *Z80) RunInstruction() uint64 {
 
 	z.incR()
 
@@ -225,18 +165,18 @@ func (z *Z80Type) RunInstruction() byte {
 
 		// Actually do the delayed interrupt disable/enable if we have one.
 		if doingDelayedDi {
-			z.Iff1 = 0
-			z.Iff2 = 0
+			z.Iff1 = false
+			z.Iff2 = false
 		} else if doingDelayedEi {
-			z.Iff1 = 1
-			z.Iff2 = 1
+			z.Iff1 = true
+			z.Iff2 = true
 		}
 
 		// And finally clear out the cycle counter for the next instruction
 		//  before returning it to the emulator core.
 		cycleCounter := z.CycleCounter
 		z.CycleCounter = 0
-		return cycleCounter
+		return uint64(cycleCounter)
 	}
 
 	// HALTED
@@ -250,7 +190,7 @@ func (z *Z80Type) RunInstruction() byte {
 //
 //	nonMaskable - true if this is a non-maskable interrupt
 //	data - the value to be placed on the data bus, if needed
-func (z *Z80Type) interrupt(nonMaskable bool, data byte) {
+func (z *Z80) interrupt(nonMaskable bool, data byte) {
 	if nonMaskable {
 		// An interrupt, if halted, does increase the PC
 		if z.Halted {
@@ -267,12 +207,12 @@ func (z *Z80Type) interrupt(nonMaskable bool, data byte) {
 
 		z.Halted = false
 		z.Iff2 = z.Iff1
-		z.Iff1 = 0
+		z.Iff1 = false
 		z.pushWord(z.PC)
 		z.PC = 0x66
 
 		z.CycleCounter += 11
-	} else if z.Iff1 != 0 {
+	} else if z.Iff1 {
 		//  An interrupt, if halted, does increase the PC
 		if z.Halted {
 			z.PC++
@@ -283,8 +223,8 @@ func (z *Z80Type) interrupt(nonMaskable bool, data byte) {
 		z.incR()
 
 		z.Halted = false
-		z.Iff1 = 0
-		z.Iff2 = 0
+		z.Iff1 = false
+		z.Iff2 = false
 
 		if z.IMode == 0 {
 			// In the 8080-compatible interrupt mode,
@@ -312,19 +252,19 @@ func (z *Z80Type) interrupt(nonMaskable bool, data byte) {
 			z.PC = z.getWord(vectorAddress) //uint16( z.core.MemRead(vectorAddress)) | (uint16(z.core.MemRead(vectorAddress+1)) << 8)
 			z.CycleCounter += 19
 			// A "notification" is generated so that the calling program can break on it.
-			z.interruptOccurred = true
+			z.InterruptOccurred = true
 		}
 	}
 }
 
-func (z *Z80Type) pushWord(operand uint16) {
+func (z *Z80) pushWord(operand uint16) {
 	z.SP--
 	z.core.MemWrite(z.SP, byte(operand>>8))
 	z.SP--
 	z.core.MemWrite(z.SP, byte(operand&0x00ff))
 }
 
-func (z *Z80Type) getOperand(opcode byte) byte {
+func (z *Z80) getOperand(opcode byte) byte {
 	switch opcode & 0x07 {
 	case 0:
 		return z.B
@@ -345,7 +285,7 @@ func (z *Z80Type) getOperand(opcode byte) byte {
 	}
 }
 
-func (z *Z80Type) decodeInstruction(opcode byte) {
+func (z *Z80) decodeInstruction(opcode byte) {
 	// Handle HALT right up front, because it fouls up our LD decoding
 	//  by falling where LD (HL), (HL) ought to be.
 	if opcode == OpHalt {
@@ -363,7 +303,7 @@ func (z *Z80Type) decodeInstruction(opcode byte) {
 	z.CycleCounter += CycleCounts[opcode]
 }
 
-func (z *Z80Type) load8bit(opcode byte, operand byte) {
+func (z *Z80) load8bit(opcode byte, operand byte) {
 	switch (opcode & 0x38) >> 3 {
 	case 0:
 		z.B = operand
@@ -385,7 +325,7 @@ func (z *Z80Type) load8bit(opcode byte, operand byte) {
 }
 
 // alu8bit Handle ALU Operations, ADD, ADC SUB, SBC, AND, XOR, OR
-func (z *Z80Type) alu8bit(opcode byte, operand byte) {
+func (z *Z80) alu8bit(opcode byte, operand byte) {
 	switch (opcode & 0x38) >> 3 {
 	case 0:
 		z.doAdd(operand)
@@ -407,16 +347,16 @@ func (z *Z80Type) alu8bit(opcode byte, operand byte) {
 }
 
 // getFlagsRegister return whole F register
-func (z *Z80Type) getFlagsRegister() byte {
+func (z *Z80) getFlagsRegister() byte {
 	return getFlags(&z.Flags)
 }
 
 // getFlagsRegister return whole F' register
-func (z *Z80Type) getFlagsPrimeRegister() byte {
+func (z *Z80) getFlagsPrimeRegister() byte {
 	return getFlags(&z.FlagsAlt)
 }
 
-func getFlags(f *FlagsType) byte {
+func getFlags(f *z80.FlagsType) byte {
 	var flags byte = 0
 	if f.S {
 		flags |= 0x80
@@ -446,15 +386,15 @@ func getFlags(f *FlagsType) byte {
 
 }
 
-func (z *Z80Type) setFlagsRegister(flags byte) {
+func (z *Z80) setFlagsRegister(flags byte) {
 	setFlags(flags, &z.Flags)
 }
 
-func (z *Z80Type) setFlagsPrimeRegister(flags byte) {
+func (z *Z80) setFlagsPrimeRegister(flags byte) {
 	setFlags(flags, &z.FlagsAlt)
 }
 
-func setFlags(flags byte, f *FlagsType) {
+func setFlags(flags byte, f *z80.FlagsType) {
 	f.S = flags&0x80 != 0
 	f.Z = flags&0x40 != 0
 	f.Y = flags&0x20 != 0
@@ -466,13 +406,13 @@ func setFlags(flags byte, f *FlagsType) {
 }
 
 // updateXYFlags Set flags X and Y based on result bits
-func (z *Z80Type) updateXYFlags(result byte) {
+func (z *Z80) updateXYFlags(result byte) {
 	z.Flags.Y = result&0x20 != 0
 	z.Flags.X = result&0x08 != 0
 }
 
 // PushWord - Decrement stack pointer and put specified word value to stack
-func (z *Z80Type) PushWord(operand uint16) {
+func (z *Z80) PushWord(operand uint16) {
 	z.SP--
 	z.core.MemWrite(z.SP, byte((operand&0xff00)>>8))
 	z.SP--
@@ -480,7 +420,7 @@ func (z *Z80Type) PushWord(operand uint16) {
 }
 
 // PopWord - Get word value from top of stack and increment stack pointer
-func (z *Z80Type) PopWord() uint16 {
+func (z *Z80) PopWord() uint16 {
 	result := uint16(z.core.MemRead(z.SP))
 	z.SP++
 	result |= uint16(z.core.MemRead(z.SP)) << 8
@@ -489,7 +429,7 @@ func (z *Z80Type) PopWord() uint16 {
 }
 
 // doConditionalAbsoluteJump - Implements the JP [condition],nn instructions.
-func (z *Z80Type) doConditionalAbsoluteJump(condition bool) {
+func (z *Z80) doConditionalAbsoluteJump(condition bool) {
 	if condition {
 		// We're taking this jump, so write the new PC,
 		//  and then decrement the thing we just wrote,
@@ -505,7 +445,7 @@ func (z *Z80Type) doConditionalAbsoluteJump(condition bool) {
 }
 
 // doConditionalRelativeJump - Implements the JR [condition],nn instructions.
-func (z *Z80Type) doConditionalRelativeJump(condition bool) {
+func (z *Z80) doConditionalRelativeJump(condition bool) {
 	if condition {
 		// We need a few more cycles to actually take the jump.
 		z.CycleCounter += 5
@@ -524,7 +464,7 @@ func (z *Z80Type) doConditionalRelativeJump(condition bool) {
 }
 
 // doConditionalCall - Implements CALL [condition],nn instructions.
-func (z *Z80Type) doConditionalCall(condition bool) {
+func (z *Z80) doConditionalCall(condition bool) {
 	if condition {
 		z.CycleCounter += 7
 		z.PushWord(z.PC + 3)
@@ -535,7 +475,7 @@ func (z *Z80Type) doConditionalCall(condition bool) {
 	}
 }
 
-func (z *Z80Type) doConditionalReturn(condition bool) {
+func (z *Z80) doConditionalReturn(condition bool) {
 	if condition {
 		z.CycleCounter += 6
 		z.PC = z.PopWord() - 1
@@ -543,13 +483,13 @@ func (z *Z80Type) doConditionalReturn(condition bool) {
 }
 
 // doReset - Implements RST [address] instructions.
-func (z *Z80Type) doReset(address uint16) {
+func (z *Z80) doReset(address uint16) {
 	z.PushWord(z.PC + 1)
 	z.PC = address - 1
 }
 
 // doAdd Handle ADD A, [operand] instructions.
-func (z *Z80Type) doAdd(operand byte) {
+func (z *Z80) doAdd(operand byte) {
 	var result = uint16(z.A) + uint16(operand)
 
 	z.Flags.S = result&0x80 != 0
@@ -564,7 +504,7 @@ func (z *Z80Type) doAdd(operand byte) {
 }
 
 // doAdc Handle ADC A, [operand] instructions.
-func (z *Z80Type) doAdc(operand byte) {
+func (z *Z80) doAdc(operand byte) {
 	add := byte(0)
 	if z.Flags.C {
 		add = 1
@@ -583,7 +523,7 @@ func (z *Z80Type) doAdc(operand byte) {
 }
 
 // doSub Handle SUB A, [operand] instructions.
-func (z *Z80Type) doSub(operand byte) {
+func (z *Z80) doSub(operand byte) {
 	var result = uint16(z.A) - uint16(operand)
 
 	z.Flags.S = result&0x80 != 0
@@ -598,7 +538,7 @@ func (z *Z80Type) doSub(operand byte) {
 }
 
 // doSbc Handle SBC A, [operand] instructions.
-func (z *Z80Type) doSbc(operand byte) {
+func (z *Z80) doSbc(operand byte) {
 	sub := byte(0)
 	if z.Flags.C {
 		sub = 1
@@ -617,7 +557,7 @@ func (z *Z80Type) doSbc(operand byte) {
 }
 
 // setLogicFlags Set common flags for logic ALU Ops
-func (z *Z80Type) setLogicFlags() {
+func (z *Z80) setLogicFlags() {
 	z.Flags.S = z.A&0x80 != 0
 	z.Flags.Z = z.A == 0
 	z.Flags.P = ParityBits[z.A]
@@ -626,7 +566,7 @@ func (z *Z80Type) setLogicFlags() {
 }
 
 // doAnd handle AND [operand] instructions.
-func (z *Z80Type) doAnd(operand byte) {
+func (z *Z80) doAnd(operand byte) {
 	z.A &= operand
 	z.setLogicFlags()
 	z.Flags.H = true
@@ -634,7 +574,7 @@ func (z *Z80Type) doAnd(operand byte) {
 }
 
 // doXor handle XOR [operand] instructions.
-func (z *Z80Type) doXor(operand byte) {
+func (z *Z80) doXor(operand byte) {
 	z.A ^= operand
 	z.setLogicFlags()
 	z.Flags.H = false
@@ -642,7 +582,7 @@ func (z *Z80Type) doXor(operand byte) {
 }
 
 // doOr handle OR [operand] instructions.
-func (z *Z80Type) doOr(operand byte) {
+func (z *Z80) doOr(operand byte) {
 	z.A |= operand
 	z.setLogicFlags()
 	z.Flags.H = false
@@ -650,7 +590,7 @@ func (z *Z80Type) doOr(operand byte) {
 }
 
 // doCp handle CP [operand] instructions.
-func (z *Z80Type) doCp(operand byte) {
+func (z *Z80) doCp(operand byte) {
 	tmp := z.A
 	z.doSub(operand)
 	z.A = tmp
@@ -658,7 +598,7 @@ func (z *Z80Type) doCp(operand byte) {
 }
 
 // doInc handle INC [operand] instructions.
-func (z *Z80Type) doInc(operand byte) byte {
+func (z *Z80) doInc(operand byte) byte {
 	var result = uint16(operand) + 1
 	r8 := byte(result & 0xff)
 
@@ -673,7 +613,7 @@ func (z *Z80Type) doInc(operand byte) byte {
 }
 
 // doDec handle DEC [operand] instructions.
-func (z *Z80Type) doDec(operand byte) byte {
+func (z *Z80) doDec(operand byte) byte {
 	var result = uint16(operand) - 1
 	r8 := byte(result & 0xff)
 
@@ -688,7 +628,7 @@ func (z *Z80Type) doDec(operand byte) byte {
 }
 
 // doHlAdd handle ADD HL,[operand] instructions.
-func (z *Z80Type) doHlAdd(operand uint16) {
+func (z *Z80) doHlAdd(operand uint16) {
 	// The HL arithmetic instructions are the same as the A ones,
 	//  just with twice as many bits happening.
 	hl := z.hl() //uint16(z.L) | (uint16(z.H) << 8)
@@ -705,7 +645,7 @@ func (z *Z80Type) doHlAdd(operand uint16) {
 }
 
 // doHlAdc handle ADC HL,[operand] instructions.
-func (z *Z80Type) doHlAdc(operand uint16) {
+func (z *Z80) doHlAdc(operand uint16) {
 	if z.Flags.C {
 		operand++
 	}
@@ -728,7 +668,7 @@ func (z *Z80Type) doHlAdc(operand uint16) {
 }
 
 // doHlSbc handle SBC HL,[operand] instructions.
-func (z *Z80Type) doHlSbc(operand uint16) {
+func (z *Z80) doHlSbc(operand uint16) {
 	if z.Flags.C {
 		operand++
 	}
@@ -750,7 +690,7 @@ func (z *Z80Type) doHlSbc(operand uint16) {
 	z.updateXYFlags(z.H)
 }
 
-func (z *Z80Type) doIn(port uint16) byte {
+func (z *Z80) doIn(port uint16) byte {
 	var result = z.core.IORead(port)
 
 	z.Flags.S = result&0x80 != 0
@@ -762,7 +702,7 @@ func (z *Z80Type) doIn(port uint16) byte {
 	return result
 }
 
-func (z *Z80Type) doNeg() {
+func (z *Z80) doNeg() {
 	// This instruction is defined to not alter the register if it === 0x80.
 	a := int8(z.A)
 	if z.A != 0x80 {
@@ -778,7 +718,7 @@ func (z *Z80Type) doNeg() {
 	z.updateXYFlags(z.A)
 }
 
-func (z *Z80Type) doLdi() {
+func (z *Z80) doLdi() {
 	// Copy the value that we're supposed to copy.
 	readValue := z.core.MemRead(z.hl())
 	z.core.MemWrite(z.de(), readValue)
@@ -794,14 +734,14 @@ func (z *Z80Type) doLdi() {
 	z.Flags.X = ((z.A+readValue)&0x08)>>3 != 0
 }
 
-func (z *Z80Type) fhv() byte {
+func (z *Z80) fhv() byte {
 	if z.Flags.H {
 		return 1
 	}
 	return 0
 }
 
-func (z *Z80Type) doCpi() {
+func (z *Z80) doCpi() {
 	tempCarry := z.Flags.C
 	readValue := z.core.MemRead(z.hl())
 	z.doCp(readValue)
@@ -815,21 +755,21 @@ func (z *Z80Type) doCpi() {
 	z.Flags.P = (z.B | z.C) != 0
 }
 
-func (z *Z80Type) doIni() {
+func (z *Z80) doIni() {
 	z.core.MemWrite(z.hl(), z.core.IORead(z.bc()))
 	z.incHl()
 	z.B = z.doDec(z.B)
 	z.Flags.N = true
 }
 
-func (z *Z80Type) doOuti() {
+func (z *Z80) doOuti() {
 	z.B = z.doDec(z.B)
 	z.core.IOWrite(z.bc(), z.core.MemRead(z.hl()))
 	z.incHl()
 	z.Flags.N = true
 }
 
-func (z *Z80Type) doLdd() {
+func (z *Z80) doLdd() {
 	z.Flags.N = false
 	z.Flags.H = false
 	readValue := z.core.MemRead(z.hl())
@@ -842,7 +782,7 @@ func (z *Z80Type) doLdd() {
 	z.Flags.X = ((z.A + readValue) & 0x08) != 0
 }
 
-func (z *Z80Type) doCpd() {
+func (z *Z80) doCpd() {
 	tempCarry := z.Flags.C
 	readValue := z.core.MemRead(z.hl())
 	z.doCp(readValue)
@@ -860,14 +800,14 @@ func (z *Z80Type) doCpd() {
 	z.Flags.P = (z.B | z.C) != 0
 }
 
-func (z *Z80Type) doInd() {
+func (z *Z80) doInd() {
 	z.core.MemWrite(z.hl(), z.core.IORead(z.bc()))
 	z.decHl()
 	z.B = z.doDec(z.B)
 	z.Flags.N = true
 }
 
-func (z *Z80Type) doOutd() {
+func (z *Z80) doOutd() {
 	z.B = z.doDec(z.B)
 	z.core.IOWrite(z.bc(), z.core.MemRead(z.hl()))
 	z.decHl()
@@ -876,7 +816,7 @@ func (z *Z80Type) doOutd() {
 
 type OpShift func(operand byte) byte
 
-func (z *Z80Type) doRlc(operand byte) byte {
+func (z *Z80) doRlc(operand byte) byte {
 	z.Flags.C = operand&0x80 != 0
 	var fc byte = 0
 	if z.Flags.C {
@@ -887,7 +827,7 @@ func (z *Z80Type) doRlc(operand byte) byte {
 	return operand
 }
 
-func (z *Z80Type) doRrc(operand byte) byte {
+func (z *Z80) doRrc(operand byte) byte {
 	z.Flags.C = operand&1 != 0
 	var fc byte = 0
 	if z.Flags.C {
@@ -898,7 +838,7 @@ func (z *Z80Type) doRrc(operand byte) byte {
 	return operand
 }
 
-func (z *Z80Type) doRl(operand byte) byte {
+func (z *Z80) doRl(operand byte) byte {
 	var fc byte = 0
 	if z.Flags.C {
 		fc = 1
@@ -909,7 +849,7 @@ func (z *Z80Type) doRl(operand byte) byte {
 	return operand
 }
 
-func (z *Z80Type) doRr(operand byte) byte {
+func (z *Z80) doRr(operand byte) byte {
 	var fc byte = 0
 	if z.Flags.C {
 		fc = 0x80
@@ -920,28 +860,28 @@ func (z *Z80Type) doRr(operand byte) byte {
 	return operand
 }
 
-func (z *Z80Type) doSla(operand byte) byte {
+func (z *Z80) doSla(operand byte) byte {
 	z.Flags.C = operand&0x80 != 0
 	operand = operand << 1
 	z.setShiftFlags(operand)
 	return operand
 }
 
-func (z *Z80Type) doSra(operand byte) byte {
+func (z *Z80) doSra(operand byte) byte {
 	z.Flags.C = operand&1 != 0
 	operand = ((operand >> 1) & 0x7f) | (operand & 0x80)
 	z.setShiftFlags(operand)
 	return operand
 }
 
-func (z *Z80Type) doSll(operand byte) byte {
+func (z *Z80) doSll(operand byte) byte {
 	z.Flags.C = operand&0x80 != 0
 	operand = (operand << 1) | 1
 	z.setShiftFlags(operand)
 	return operand
 }
 
-func (z *Z80Type) doSrl(operand byte) byte {
+func (z *Z80) doSrl(operand byte) byte {
 	z.Flags.C = operand&1 != 0
 	operand = (operand >> 1) & 0x7f
 	z.setShiftFlags(operand)
@@ -949,7 +889,7 @@ func (z *Z80Type) doSrl(operand byte) byte {
 	return operand
 }
 
-func (z *Z80Type) doIxAdd(operand uint16) {
+func (z *Z80) doIxAdd(operand uint16) {
 	z.Flags.N = false
 	result := uint32(z.IX) + uint32(operand)
 	z.Flags.C = result > 0xffff
@@ -959,7 +899,7 @@ func (z *Z80Type) doIxAdd(operand uint16) {
 	z.IX = uint16(result & 0xffff)
 }
 
-func (z *Z80Type) setShiftFlags(operand byte) {
+func (z *Z80) setShiftFlags(operand byte) {
 	z.Flags.N = false
 	z.Flags.H = false
 	z.Flags.Z = operand == 0
@@ -970,55 +910,55 @@ func (z *Z80Type) setShiftFlags(operand byte) {
 
 // ============== get register pairs
 
-func (z *Z80Type) bc() uint16 {
+func (z *Z80) bc() uint16 {
 	return (uint16(z.B) << 8) | uint16(z.C)
 }
 
-func (z *Z80Type) de() uint16 {
+func (z *Z80) de() uint16 {
 	return (uint16(z.D) << 8) | uint16(z.E)
 }
 
-func (z *Z80Type) hl() uint16 {
+func (z *Z80) hl() uint16 {
 	return (uint16(z.H) << 8) | uint16(z.L)
 }
 
 // ============ helper fn
 
-func (z *Z80Type) incBc() {
+func (z *Z80) incBc() {
 	z.setBc(z.bc() + 1)
 }
 
-func (z *Z80Type) decBc() {
+func (z *Z80) decBc() {
 	z.setBc(z.bc() - 1)
 }
 
-func (z *Z80Type) incDe() {
+func (z *Z80) incDe() {
 	z.setDe(z.de() + 1)
 }
 
-func (z *Z80Type) decDe() {
+func (z *Z80) decDe() {
 	z.setDe(z.de() - 1)
 }
 
-func (z *Z80Type) incHl() {
+func (z *Z80) incHl() {
 	z.setHl(z.hl() + 1)
 }
 
-func (z *Z80Type) decHl() {
+func (z *Z80) decHl() {
 	z.setHl(z.hl() - 1)
 }
 
-func (z *Z80Type) setHl(val uint16) {
+func (z *Z80) setHl(val uint16) {
 	z.L = byte(val & 0xff)
 	z.H = byte(val >> 8)
 }
 
-func (z *Z80Type) setDe(val uint16) {
+func (z *Z80) setDe(val uint16) {
 	z.E = byte(val & 0xff)
 	z.D = byte(val >> 8)
 }
 
-func (z *Z80Type) setBc(val uint16) {
+func (z *Z80) setBc(val uint16) {
 	z.C = byte(val & 0xff)
 	z.B = byte(val >> 8)
 }
@@ -1027,16 +967,25 @@ func (z *Z80Type) setBc(val uint16) {
 // The high bit of R is not affected by this increment,
 // it can only be changed using the LD R, A instruction.
 // Note: also a HALT does increment the R register.
-func (z *Z80Type) incR() {
+func (z *Z80) incR() {
 	z.R = (z.R & 0x80) | (((z.R & 0x7f) + 1) & 0x7f)
 }
 
 // getWord Return 16bit value from memory by specified address
-func (z *Z80Type) getWord(address uint16) uint16 {
+func (z *Z80) getWord(address uint16) uint16 {
 	return (uint16(z.core.MemRead(address+1)) << 8) | uint16(z.core.MemRead(address))
 }
 
-func (z *Z80Type) setWord(address uint16, value uint16) {
+func (z *Z80) setWord(address uint16, value uint16) {
 	z.core.MemWrite(address, byte(value))
 	z.core.MemWrite(address+1, byte(value>>8))
 }
+
+func (z *Z80) debugOutput() {
+	log.Debugf("PC: %04X, AF: %04X, BC: %04X, DE: %04X, HL: %04X, SP: %04X, IX: %04X, IY: %04X, I: %02X, R: %02X",
+		z.PC, (uint16(z.A)<<8)|uint16(z.getFlagsRegister()), z.bc(), z.de(), z.hl(), z.SP,
+		z.IX, z.IY, z.I, z.R)
+
+	log.Debugf("\t(%02X %02X %02X %02X), cyc: %d\n", z.core.MemRead(z.PC), z.core.MemRead(z.PC+1),
+		z.core.MemRead(z.PC+2), z.core.MemRead(z.PC+3), z.CycleCounter)
+}
diff --git a/z80em/opcode.go b/z80/js/opcode.go
similarity index 74%
rename from z80em/opcode.go
rename to z80/js/opcode.go
index fda8fcb..8b3fe5b 100644
--- a/z80em/opcode.go
+++ b/z80/js/opcode.go
@@ -1,40 +1,40 @@
-package z80em
+package js
 
-var instructions = []func(s *Z80Type){
+var instructions = []func(s *Z80){
 	// NOP
-	0x00: func(s *Z80Type) {
+	0x00: func(s *Z80) {
 		// NOP
 	},
 	// LD BC, nn
-	0x01: func(s *Z80Type) {
+	0x01: func(s *Z80) {
 		s.PC++
 		s.C = s.core.MemRead(s.PC)
 		s.PC++
 		s.B = s.core.MemRead(s.PC)
 	},
 	// LD (BC), A
-	0x02: func(s *Z80Type) {
+	0x02: func(s *Z80) {
 		s.core.MemWrite(s.bc(), s.A)
 	},
 	// 0x03 : INC BC
-	0x03: func(s *Z80Type) {
+	0x03: func(s *Z80) {
 		s.incBc()
 	},
 	// 0x04 : INC B
-	0x04: func(s *Z80Type) {
+	0x04: func(s *Z80) {
 		s.B = s.doInc(s.B)
 	},
 	// 0x05 : DEC B
-	0x05: func(s *Z80Type) {
+	0x05: func(s *Z80) {
 		s.B = s.doDec(s.B)
 	},
 	// 0x06 : LD B, n
-	0x06: func(s *Z80Type) {
+	0x06: func(s *Z80) {
 		s.PC++
 		s.B = s.core.MemRead(s.PC)
 	},
 	// 0x07 : RLCA
-	0x07: func(s *Z80Type) {
+	0x07: func(s *Z80) {
 		// This instruction is implemented as a special case of the
 		//  more general Z80-specific RLC instruction.
 		// Specifially, RLCA is a version of RLC A that affects fewer flags.
@@ -48,39 +48,39 @@ var instructions = []func(s *Z80Type){
 		s.Flags.P = tempP
 	},
 	// 0x08 : EX AF, AF'
-	0x08: func(s *Z80Type) {
+	0x08: func(s *Z80) {
 		s.A, s.AAlt = s.AAlt, s.A
 		temp := s.getFlagsRegister()
 		s.setFlagsRegister(s.getFlagsPrimeRegister())
 		s.setFlagsPrimeRegister(temp)
 	},
 	// 0x09 : ADD HL, BC
-	0x09: func(s *Z80Type) {
+	0x09: func(s *Z80) {
 		s.doHlAdd(s.bc())
 	},
 	// 0x0a : LD A, (BC)
-	0x0A: func(s *Z80Type) {
+	0x0A: func(s *Z80) {
 		s.A = s.core.MemRead(s.bc())
 	},
 	// 0x0b : DEC BC
-	0x0B: func(s *Z80Type) {
+	0x0B: func(s *Z80) {
 		s.decBc()
 	},
 	// 0x0c : INC C
-	0x0C: func(s *Z80Type) {
+	0x0C: func(s *Z80) {
 		s.C = s.doInc(s.C)
 	},
 	// 0x0d : DEC C
-	0x0D: func(s *Z80Type) {
+	0x0D: func(s *Z80) {
 		s.C = s.doDec(s.C)
 	},
 	// 0x0e : LD C, n
-	0x0E: func(s *Z80Type) {
+	0x0E: func(s *Z80) {
 		s.PC++
 		s.C = s.core.MemRead(s.PC)
 	},
 	// 0x0f : RRCA
-	0x0F: func(s *Z80Type) {
+	0x0F: func(s *Z80) {
 		tempS := s.Flags.S
 		tempZ := s.Flags.Z
 		tempP := s.Flags.P
@@ -90,40 +90,40 @@ var instructions = []func(s *Z80Type){
 		s.Flags.P = tempP
 	},
 	// 0x10 : DJNZ nn
-	0x10: func(s *Z80Type) {
+	0x10: func(s *Z80) {
 		s.B--
 		s.doConditionalRelativeJump(s.B != 0)
 	},
 	// 0x11 : LD DE, nn
-	0x11: func(s *Z80Type) {
+	0x11: func(s *Z80) {
 		s.PC++
 		s.E = s.core.MemRead(s.PC)
 		s.PC++
 		s.D = s.core.MemRead(s.PC)
 	},
 	// 0x12 : LD (DE), A
-	0x12: func(s *Z80Type) {
+	0x12: func(s *Z80) {
 		s.core.MemWrite(s.de(), s.A)
 	},
 	// 0x13 : INC DE
-	0x13: func(s *Z80Type) {
+	0x13: func(s *Z80) {
 		s.incDe()
 	},
 	// 0x14 : INC D
-	0x14: func(s *Z80Type) {
+	0x14: func(s *Z80) {
 		s.D = s.doInc(s.D)
 	},
 	// 0x15 : DEC D
-	0x15: func(s *Z80Type) {
+	0x15: func(s *Z80) {
 		s.D = s.doDec(s.D)
 	},
 	// 0x16 : LD D, n
-	0x16: func(s *Z80Type) {
+	0x16: func(s *Z80) {
 		s.PC++
 		s.D = s.core.MemRead(s.PC)
 	},
 	// 0x17 : RLA
-	0x17: func(s *Z80Type) {
+	0x17: func(s *Z80) {
 		tempS := s.Flags.S
 		tempZ := s.Flags.Z
 		tempP := s.Flags.P
@@ -133,7 +133,7 @@ var instructions = []func(s *Z80Type){
 		s.Flags.P = tempP
 	},
 	// 0x18 : JR n
-	0x18: func(s *Z80Type) {
+	0x18: func(s *Z80) {
 		var o = int8(s.core.MemRead(s.PC + 1))
 		if o > 0 {
 			s.PC += uint16(o)
@@ -143,32 +143,32 @@ var instructions = []func(s *Z80Type){
 		s.PC++
 	},
 	// 0x19 : ADD HL, DE
-	0x19: func(s *Z80Type) {
+	0x19: func(s *Z80) {
 		s.doHlAdd(s.de())
 	},
 	// 0x1a : LD A, (DE)
-	0x1A: func(s *Z80Type) {
+	0x1A: func(s *Z80) {
 		s.A = s.core.MemRead(s.de())
 	},
 	// 0x1b : DEC DE
-	0x1B: func(s *Z80Type) {
+	0x1B: func(s *Z80) {
 		s.decDe()
 	},
 	// 0x1c : INC E
-	0x1C: func(s *Z80Type) {
+	0x1C: func(s *Z80) {
 		s.E = s.doInc(s.E)
 	},
 	// 0x1d : DEC E
-	0x1D: func(s *Z80Type) {
+	0x1D: func(s *Z80) {
 		s.E = s.doDec(s.E)
 	},
 	// 0x1e : LD E, n
-	0x1E: func(s *Z80Type) {
+	0x1E: func(s *Z80) {
 		s.PC++
 		s.E = s.core.MemRead(s.PC)
 	},
 	// 0x1f : RRA
-	0x1F: func(s *Z80Type) {
+	0x1F: func(s *Z80) {
 		tempS := s.Flags.S
 		tempZ := s.Flags.Z
 		tempP := s.Flags.P
@@ -178,41 +178,41 @@ var instructions = []func(s *Z80Type){
 		s.Flags.P = tempP
 	},
 	// 0x20 : JR NZ, n
-	0x20: func(s *Z80Type) {
+	0x20: func(s *Z80) {
 		s.doConditionalRelativeJump(!s.Flags.Z)
 	},
 	// 0x21 : LD HL, nn
-	0x21: func(s *Z80Type) {
+	0x21: func(s *Z80) {
 		s.PC++
 		s.L = s.core.MemRead(s.PC)
 		s.PC++
 		s.H = s.core.MemRead(s.PC)
 	},
 	// 0x22 : LD (nn), HL
-	0x22: func(s *Z80Type) {
+	0x22: func(s *Z80) {
 		addr := s.nextWord()
 		s.core.MemWrite(addr, s.L)
 		s.core.MemWrite(addr+1, s.H)
 	},
 	// 0x23 : INC HL
-	0x23: func(s *Z80Type) {
+	0x23: func(s *Z80) {
 		s.incHl()
 	},
 	// 0x24 : INC H
-	0x24: func(s *Z80Type) {
+	0x24: func(s *Z80) {
 		s.H = s.doInc(s.H)
 	},
 	// 0x25 : DEC H
-	0x25: func(s *Z80Type) {
+	0x25: func(s *Z80) {
 		s.H = s.doDec(s.H)
 	},
 	// 0x26 : LD H, n
-	0x26: func(s *Z80Type) {
+	0x26: func(s *Z80) {
 		s.PC++
 		s.H = s.core.MemRead(s.PC)
 	},
 	// 0x27 : DAA
-	0x27: func(s *Z80Type) {
+	0x27: func(s *Z80) {
 		temp := s.A
 		if !s.Flags.N {
 			if s.Flags.H || ((s.A & 0x0f) > 9) {
@@ -243,231 +243,231 @@ var instructions = []func(s *Z80Type){
 		s.updateXYFlags(s.A)
 	},
 	// 0x28 : JR Z, n
-	0x28: func(s *Z80Type) {
+	0x28: func(s *Z80) {
 		s.doConditionalRelativeJump(s.Flags.Z)
 	},
 	// 0x29 : ADD HL, HL
-	0x29: func(s *Z80Type) {
+	0x29: func(s *Z80) {
 		s.doHlAdd(s.hl())
 	},
 	// 0x2a : LD HL, (nn)
-	0x2A: func(s *Z80Type) {
+	0x2A: func(s *Z80) {
 		addr := s.nextWord()
 		s.L = s.core.MemRead(addr)
 		s.H = s.core.MemRead(addr + 1)
 	},
 	// 0x2b : DEC HL
-	0x2B: func(s *Z80Type) {
+	0x2B: func(s *Z80) {
 		s.decHl()
 	},
 	// 0x2c : INC L
-	0x2C: func(s *Z80Type) {
+	0x2C: func(s *Z80) {
 		s.L = s.doInc(s.L)
 	},
 	// 0x2d : DEC L
-	0x2D: func(s *Z80Type) {
+	0x2D: func(s *Z80) {
 		s.L = s.doDec(s.L)
 	},
 	// 0x2e : LD L, n
-	0x2E: func(s *Z80Type) {
+	0x2E: func(s *Z80) {
 		s.PC++
 		s.L = s.core.MemRead(s.PC)
 	},
 	// 0x2f : CPL
-	0x2F: func(s *Z80Type) {
+	0x2F: func(s *Z80) {
 		s.A = ^s.A
 		s.Flags.N = true
 		s.Flags.H = true
 		s.updateXYFlags(s.A)
 	},
 	// 0x30 : JR NC, n
-	0x30: func(s *Z80Type) {
+	0x30: func(s *Z80) {
 		s.doConditionalRelativeJump(!s.Flags.C)
 	},
 	// 0x31 : LD SP, nn
-	0x31: func(s *Z80Type) {
+	0x31: func(s *Z80) {
 		s.PC++
 		lo := s.core.MemRead(s.PC)
 		s.PC++
 		s.SP = (uint16(s.core.MemRead(s.PC)) << 8) | uint16(lo)
 	},
 	// 0x32 : LD (nn), A
-	0x32: func(s *Z80Type) {
+	0x32: func(s *Z80) {
 		s.core.MemWrite(s.nextWord(), s.A)
 	},
 	// 0x33 : INC SP
-	0x33: func(s *Z80Type) {
+	0x33: func(s *Z80) {
 		s.SP++
 	},
 	// 0x34 : INC (HL)
-	0x34: func(s *Z80Type) {
+	0x34: func(s *Z80) {
 		s.core.MemWrite(s.hl(), s.doInc(s.core.MemRead(s.hl())))
 	},
 	// 0x35 : DEC (HL)
-	0x35: func(s *Z80Type) {
+	0x35: func(s *Z80) {
 		s.core.MemWrite(s.hl(), s.doDec(s.core.MemRead(s.hl())))
 	},
 	// 0x36 : LD (HL), n
-	0x36: func(s *Z80Type) {
+	0x36: func(s *Z80) {
 		s.PC++
 		s.core.MemWrite(s.hl(), s.core.MemRead(s.PC))
 	},
 	// 0x37 : SCF
-	0x37: func(s *Z80Type) {
+	0x37: func(s *Z80) {
 		s.Flags.N = false
 		s.Flags.H = false
 		s.Flags.C = true
 		s.updateXYFlags(s.A)
 	},
 	// 0x38 : JR C, n
-	0x38: func(s *Z80Type) {
+	0x38: func(s *Z80) {
 		s.doConditionalRelativeJump(s.Flags.C)
 	},
 	// 0x39 : ADD HL, SP
-	0x39: func(s *Z80Type) {
+	0x39: func(s *Z80) {
 		s.doHlAdd(s.SP)
 	},
 	// 0x3a : LD A, (nn)
-	0x3A: func(s *Z80Type) {
+	0x3A: func(s *Z80) {
 		s.A = s.core.MemRead(s.nextWord())
 	},
 	// 0x3b : DEC SP
-	0x3B: func(s *Z80Type) {
+	0x3B: func(s *Z80) {
 		s.SP--
 	},
 	// 0x3c : INC A
-	0x3C: func(s *Z80Type) {
+	0x3C: func(s *Z80) {
 		s.A = s.doInc(s.A)
 	},
 	// 0x3d : DEC A
-	0x3D: func(s *Z80Type) {
+	0x3D: func(s *Z80) {
 		s.A = s.doDec(s.A)
 	},
 	// 0x3e : LD A, n
-	0x3E: func(s *Z80Type) {
+	0x3E: func(s *Z80) {
 		s.PC++
 		s.A = s.core.MemRead(s.PC)
 	},
 	// 0x3f : CCF
-	0x3F: func(s *Z80Type) {
+	0x3F: func(s *Z80) {
 		s.Flags.N = false
 		s.Flags.H = s.Flags.C
 		s.Flags.C = !s.Flags.C
 		s.updateXYFlags(s.A)
 	},
 	// 0xc0 : RET NZ
-	0xC0: func(s *Z80Type) {
+	0xC0: func(s *Z80) {
 		s.doConditionalReturn(!s.Flags.Z)
 	},
 	// 0xc1 : POP BC
-	0xC1: func(s *Z80Type) {
+	0xC1: func(s *Z80) {
 		result := s.PopWord()
 		s.C = byte(result & 0xff)
 		s.B = byte((result & 0xff00) >> 8)
 	},
 	// 0xc2 : JP NZ, nn
-	0xC2: func(s *Z80Type) {
+	0xC2: func(s *Z80) {
 		s.doConditionalAbsoluteJump(!s.Flags.Z)
 	},
 	// 0xc3 : JP nn
-	0xC3: func(s *Z80Type) {
+	0xC3: func(s *Z80) {
 		s.PC = uint16(s.core.MemRead(s.PC+1)) | (uint16(s.core.MemRead(s.PC+2)) << 8)
 		s.PC--
 	},
 	// 0xc4 : CALL NZ, nn
-	0xC4: func(s *Z80Type) {
+	0xC4: func(s *Z80) {
 		s.doConditionalCall(!s.Flags.Z)
 	},
 	// 0xc5 : PUSH BC
-	0xC5: func(s *Z80Type) {
+	0xC5: func(s *Z80) {
 		s.pushWord((uint16(s.B) << 8) | uint16(s.C))
 	},
 	// 0xc6 : ADD A, n
-	0xC6: func(s *Z80Type) {
+	0xC6: func(s *Z80) {
 		s.PC++
 		s.doAdd(s.core.MemRead(s.PC))
 	},
 	// 0xc7 : RST 00h
-	0xC7: func(s *Z80Type) {
+	0xC7: func(s *Z80) {
 		s.doReset(0x0000)
 	},
 	// 0xc8 : RET Z
-	0xC8: func(s *Z80Type) {
+	0xC8: func(s *Z80) {
 		s.doConditionalReturn(s.Flags.Z)
 	},
 	// 0xc9 : RET
-	0xC9: func(s *Z80Type) {
+	0xC9: func(s *Z80) {
 		s.PC = s.PopWord() - 1
 	},
 	// 0xca : JP Z, nn
-	0xCA: func(s *Z80Type) {
+	0xCA: func(s *Z80) {
 		s.doConditionalAbsoluteJump(s.Flags.Z)
 	},
 	// 0xcb : CB Prefix
-	0xCB: func(s *Z80Type) {
+	0xCB: func(s *Z80) {
 		s.opcodeCB()
 	},
 	// 0xcc : CALL Z, nn
-	0xCC: func(s *Z80Type) {
+	0xCC: func(s *Z80) {
 		s.doConditionalCall(s.Flags.Z)
 	},
 	// 0xcd : CALL nn
-	0xCD: func(s *Z80Type) {
+	0xCD: func(s *Z80) {
 		s.pushWord(s.PC + 3)
 		s.PC = uint16(s.core.MemRead(s.PC+1)) | (uint16(s.core.MemRead(s.PC+2)) << 8)
 		s.PC--
 	},
 	// 0xce : ADC A, n
-	0xCE: func(s *Z80Type) {
+	0xCE: func(s *Z80) {
 		s.PC++
 		s.doAdc(s.core.MemRead(s.PC))
 	},
 	// 0xcf : RST 08h
-	0xCF: func(s *Z80Type) {
+	0xCF: func(s *Z80) {
 		s.doReset(0x0008)
 	},
 	// 0xd0 : RET NC
-	0xD0: func(s *Z80Type) {
+	0xD0: func(s *Z80) {
 		s.doConditionalReturn(!s.Flags.C)
 	},
 	// 0xd1 : POP DE
-	0xD1: func(s *Z80Type) {
+	0xD1: func(s *Z80) {
 		result := s.PopWord()
 		s.E = byte(result & 0xff)
 		s.D = byte((result & 0xff00) >> 8)
 	},
 	// 0xd2 : JP NC, nn
-	0xD2: func(s *Z80Type) {
+	0xD2: func(s *Z80) {
 		s.doConditionalAbsoluteJump(!s.Flags.C)
 	},
 	// 0xd3 : OUT (n), A
-	0xD3: func(s *Z80Type) {
+	0xD3: func(s *Z80) {
 		s.PC++
 		s.core.IOWrite((uint16(s.A)<<8)|uint16(s.core.MemRead(s.PC)), s.A)
 	},
 	// 0xd4 : CALL NC, nn
-	0xD4: func(s *Z80Type) {
+	0xD4: func(s *Z80) {
 		s.doConditionalCall(!s.Flags.C)
 	},
 	// 0xd5 : PUSH DE
-	0xD5: func(s *Z80Type) {
+	0xD5: func(s *Z80) {
 		s.pushWord((uint16(s.D) << 8) | uint16(s.E))
 	},
 	// 0xd6 : SUB n
-	0xD6: func(s *Z80Type) {
+	0xD6: func(s *Z80) {
 		s.PC++
 		s.doSub(s.core.MemRead(s.PC))
 	},
 	// 0xd7 : RST 10h
-	0xD7: func(s *Z80Type) {
+	0xD7: func(s *Z80) {
 		s.doReset(0x0010)
 	},
 	// 0xd8 : RET C
-	0xD8: func(s *Z80Type) {
+	0xD8: func(s *Z80) {
 		s.doConditionalReturn(s.Flags.C)
 	},
 	// 0xd9 : EXX
-	0xD9: func(s *Z80Type) {
+	0xD9: func(s *Z80) {
 		s.B, s.BAlt = s.BAlt, s.B
 		s.C, s.CAlt = s.CAlt, s.C
 		s.D, s.DAlt = s.DAlt, s.D
@@ -476,47 +476,47 @@ var instructions = []func(s *Z80Type){
 		s.L, s.LAlt = s.LAlt, s.L
 	},
 	// 0xda : JP C, nn
-	0xDA: func(s *Z80Type) {
+	0xDA: func(s *Z80) {
 		s.doConditionalAbsoluteJump(s.Flags.C)
 	},
 	// 0xdb : IN A, (n)
-	0xDB: func(s *Z80Type) {
+	0xDB: func(s *Z80) {
 		s.PC++
 		s.A = s.core.IORead((uint16(s.A) << 8) | uint16(s.core.MemRead(s.PC)))
 	},
 	// 0xdc : CALL C, nn
-	0xDC: func(s *Z80Type) {
+	0xDC: func(s *Z80) {
 		s.doConditionalCall(s.Flags.C)
 	},
 	// 0xdd : DD Prefix (IX instructions)
-	0xDD: func(s *Z80Type) {
+	0xDD: func(s *Z80) {
 		s.opcodeDD()
 	},
 	// 0xde : SBC n
-	0xDE: func(s *Z80Type) {
+	0xDE: func(s *Z80) {
 		s.PC++
 		s.doSbc(s.core.MemRead(s.PC))
 	},
 	// 0xdf : RST 18h
-	0xDF: func(s *Z80Type) {
+	0xDF: func(s *Z80) {
 		s.doReset(0x0018)
 	},
 	// 0xe0 : RET PO
-	0xE0: func(s *Z80Type) {
+	0xE0: func(s *Z80) {
 		s.doConditionalReturn(!s.Flags.P)
 	},
 	// 0xe1 : POP HL
-	0xE1: func(s *Z80Type) {
+	0xE1: func(s *Z80) {
 		result := s.PopWord()
 		s.L = byte(result & 0xff)
 		s.H = byte((result & 0xff00) >> 8)
 	},
 	// 0xe2 : JP PO, (nn)
-	0xE2: func(s *Z80Type) {
+	0xE2: func(s *Z80) {
 		s.doConditionalAbsoluteJump(!s.Flags.P)
 	},
 	// 0xe3 : EX (SP), HL
-	0xE3: func(s *Z80Type) {
+	0xE3: func(s *Z80) {
 		temp := s.core.MemRead(s.SP)
 		s.core.MemWrite(s.SP, s.L)
 		s.L = temp
@@ -525,130 +525,130 @@ var instructions = []func(s *Z80Type){
 		s.H = temp
 	},
 	// 0xe4 : CALL PO, nn
-	0xE4: func(s *Z80Type) {
+	0xE4: func(s *Z80) {
 		s.doConditionalCall(!s.Flags.P)
 	},
 	// 0xe5 : PUSH HL
-	0xE5: func(s *Z80Type) {
+	0xE5: func(s *Z80) {
 		s.pushWord((uint16(s.H) << 8) | uint16(s.L))
 	},
 	// 0xe6 : AND n
-	0xE6: func(s *Z80Type) {
+	0xE6: func(s *Z80) {
 		s.PC++
 		s.doAnd(s.core.MemRead(s.PC))
 	},
 	// 0xe7 : RST 20h
-	0xE7: func(s *Z80Type) {
+	0xE7: func(s *Z80) {
 		s.doReset(0x0020)
 	},
 	// 0xe8 : RET PE
-	0xE8: func(s *Z80Type) {
+	0xE8: func(s *Z80) {
 		s.doConditionalReturn(s.Flags.P)
 	},
 	// 0xe9 : JP (HL)
-	0xE9: func(s *Z80Type) {
+	0xE9: func(s *Z80) {
 		s.PC = uint16(s.H)<<8 | uint16(s.L)
 		s.PC--
 	},
 	// 0xea : JP PE, nn
-	0xEA: func(s *Z80Type) {
+	0xEA: func(s *Z80) {
 		s.doConditionalAbsoluteJump(s.Flags.P)
 	},
 	// 0xeb : EX DE, HL
-	0xEB: func(s *Z80Type) {
+	0xEB: func(s *Z80) {
 		s.D, s.H = s.H, s.D
 		s.E, s.L = s.L, s.E
 	},
 	// 0xec : CALL PE, nn
-	0xEC: func(s *Z80Type) {
+	0xEC: func(s *Z80) {
 		s.doConditionalCall(s.Flags.P)
 	},
 	// 0xed : ED Prefix
-	0xED: func(s *Z80Type) {
+	0xED: func(s *Z80) {
 		s.opcodeED()
 	},
 	// 0xee : XOR n
-	0xEE: func(s *Z80Type) {
+	0xEE: func(s *Z80) {
 		s.PC++
 		s.doXor(s.core.MemRead(s.PC))
 	},
 	// 0xef : RST 28h
-	0xEF: func(s *Z80Type) {
+	0xEF: func(s *Z80) {
 		s.doReset(0x0028)
 	},
 	// 0xf0 : RET P
-	0xF0: func(s *Z80Type) {
+	0xF0: func(s *Z80) {
 		s.doConditionalReturn(!s.Flags.S)
 	},
 	// 0xf1 : POP AF
-	0xF1: func(s *Z80Type) {
+	0xF1: func(s *Z80) {
 		var result = s.PopWord()
 		s.setFlagsRegister(byte(result & 0xff))
 		s.A = byte((result & 0xff00) >> 8)
 	},
 	// 0xf2 : JP P, nn
-	0xF2: func(s *Z80Type) {
+	0xF2: func(s *Z80) {
 		s.doConditionalAbsoluteJump(!s.Flags.S)
 	},
 	// 0xf3 : DI
-	0xF3: func(s *Z80Type) {
+	0xF3: func(s *Z80) {
 		// DI doesn't actually take effect until after the next instruction.
 		s.DoDelayedDI = true
 	},
 	// 0xf4 : CALL P, nn
-	0xF4: func(s *Z80Type) {
+	0xF4: func(s *Z80) {
 		s.doConditionalCall(!s.Flags.S)
 	},
 	// 0xf5 : PUSH AF
-	0xF5: func(s *Z80Type) {
+	0xF5: func(s *Z80) {
 		s.pushWord(uint16(s.getFlagsRegister()) | (uint16(s.A) << 8))
 	},
 	// 0xf6 : OR n
-	0xF6: func(s *Z80Type) {
+	0xF6: func(s *Z80) {
 		s.PC++
 		s.doOr(s.core.MemRead(s.PC))
 	},
 	// 0xf7 : RST 30h
-	0xF7: func(s *Z80Type) {
+	0xF7: func(s *Z80) {
 		s.doReset(0x0030)
 	},
 	// 0xf8 : RET M
-	0xF8: func(s *Z80Type) {
+	0xF8: func(s *Z80) {
 		s.doConditionalReturn(s.Flags.S)
 	},
 	// 0xf9 : LD SP, HL
-	0xF9: func(s *Z80Type) {
+	0xF9: func(s *Z80) {
 		s.SP = uint16(s.H)<<8 | uint16(s.L)
 	},
 	// 0xfa : JP M, nn
-	0xFA: func(s *Z80Type) {
+	0xFA: func(s *Z80) {
 		s.doConditionalAbsoluteJump(s.Flags.S)
 	},
 	// 0xfb : EI
-	0xFB: func(s *Z80Type) {
+	0xFB: func(s *Z80) {
 		// EI doesn't actually take effect until after the next instruction.
 		s.DoDelayedEI = true
 	},
 	// 0xfc : CALL M, nn
-	0xFC: func(s *Z80Type) {
+	0xFC: func(s *Z80) {
 		s.doConditionalCall(s.Flags.S)
 	},
 	// 0xfd : FD Prefix (IY instructions)
-	0xFD: func(s *Z80Type) {
+	0xFD: func(s *Z80) {
 		s.opcodeFD()
 	},
 	// 0xfe : CP n
-	0xFE: func(s *Z80Type) {
+	0xFE: func(s *Z80) {
 		s.PC++
 		s.doCp(s.core.MemRead(s.PC))
 	},
 	// 0xff : RST 38h
-	0xFF: func(s *Z80Type) {
+	0xFF: func(s *Z80) {
 		s.doReset(0x0038)
 	},
 }
 
-func (z *Z80Type) nextWord() uint16 {
+func (z *Z80) nextWord() uint16 {
 	z.PC++
 	word := uint16(z.core.MemRead(z.PC))
 	z.PC++
diff --git a/z80em/opcodeCB.go b/z80/js/opcodeCB.go
similarity index 98%
rename from z80em/opcodeCB.go
rename to z80/js/opcodeCB.go
index 7d8fc42..c5d9039 100644
--- a/z80em/opcodeCB.go
+++ b/z80/js/opcodeCB.go
@@ -1,6 +1,6 @@
-package z80em
+package js
 
-func (z *Z80Type) opcodeCB() {
+func (z *Z80) opcodeCB() {
 	z.incR()
 	z.PC++
 	opcode := z.core.M1MemRead(z.PC)
diff --git a/z80em/opcodeDD.go b/z80/js/opcodeDD.go
similarity index 78%
rename from z80em/opcodeDD.go
rename to z80/js/opcodeDD.go
index f6ce39a..6d87033 100644
--- a/z80em/opcodeDD.go
+++ b/z80/js/opcodeDD.go
@@ -1,361 +1,361 @@
-package z80em
+package js
 
-var ddInstructions = []func(s *Z80Type){
+var ddInstructions = []func(s *Z80){
 	// 0x09 : ADD IX, BC
-	0x09: func(s *Z80Type) {
+	0x09: func(s *Z80) {
 		s.doIxAdd(s.bc())
 	},
 	// 0x19 : ADD IX, DE
-	0x19: func(s *Z80Type) {
+	0x19: func(s *Z80) {
 		s.doIxAdd(s.de())
 	},
 	// 0x21 : LD IX, nn
-	0x21: func(s *Z80Type) {
+	0x21: func(s *Z80) {
 		s.IX = s.nextWord()
 	},
 	// 0x22 : LD (nn), IX
-	0x22: func(s *Z80Type) {
+	0x22: func(s *Z80) {
 		s.setWord(s.nextWord(), s.IX)
 	},
 	// 0x23 : INC IX
-	0x23: func(s *Z80Type) {
+	0x23: func(s *Z80) {
 		s.IX++
 	},
 	// 0x24 : INC IXH (Undocumented)
-	0x24: func(s *Z80Type) {
+	0x24: func(s *Z80) {
 		s.IX = (uint16(s.doInc(byte(s.IX>>8))) << 8) | (s.IX & 0x00ff)
 	},
 	// 0x25 : DEC IXH (Undocumented)
-	0x25: func(s *Z80Type) {
+	0x25: func(s *Z80) {
 		s.IX = (uint16(s.doDec(byte(s.IX>>8))) << 8) | (s.IX & 0x00ff)
 	},
 	// 0x26 : LD IXH, n (Undocumented)
-	0x26: func(s *Z80Type) {
+	0x26: func(s *Z80) {
 		s.PC++
 		s.IX = (uint16(s.core.MemRead(s.PC)) << 8) | (s.IX & 0x00ff)
 	},
 	// 0x29 : ADD IX, IX
-	0x29: func(s *Z80Type) {
+	0x29: func(s *Z80) {
 		s.doIxAdd(s.IX)
 	},
 	// 0x2a : LD IX, (nn)
-	0x2A: func(s *Z80Type) {
+	0x2A: func(s *Z80) {
 		s.IX = s.getWord(s.nextWord())
 	},
 	// 0x2b : DEC IX
-	0x2B: func(s *Z80Type) {
+	0x2B: func(s *Z80) {
 		s.IX--
 	},
 	// 0x2c : INC IXL (Undocumented)
-	0x2C: func(s *Z80Type) {
+	0x2C: func(s *Z80) {
 		s.IX = (uint16(s.doInc(byte(s.IX & 0x00ff)))) | (s.IX & 0xff00)
 	},
 	// 0x2d : DEC IXL (Undocumented)
-	0x2D: func(s *Z80Type) {
+	0x2D: func(s *Z80) {
 		s.IX = (uint16(s.doDec(byte(s.IX & 0x00ff)))) | (s.IX & 0xff00)
 	},
 	// 0x2e : LD IXL, n (Undocumented)
-	0x2E: func(s *Z80Type) {
+	0x2E: func(s *Z80) {
 		s.PC++
 		s.IX = (uint16(s.core.MemRead(s.PC))) | (s.IX & 0xff00)
 	},
 	// 0x34 : INC (IX+n)
-	0x34: func(s *Z80Type) {
+	0x34: func(s *Z80) {
 		offset := s.getOffset(s.IX)
 		value := s.core.MemRead(offset)
 		s.core.MemWrite(offset, s.doInc(value))
 	},
 	// 0x35 : DEC (IX+n)
-	0x35: func(s *Z80Type) {
+	0x35: func(s *Z80) {
 		offset := s.getOffset(s.IX)
 		value := s.core.MemRead(offset)
 		s.core.MemWrite(offset, s.doDec(value))
 	},
 	// 0x36 : LD (IX+n), n
-	0x36: func(s *Z80Type) {
+	0x36: func(s *Z80) {
 		offset := s.getOffset(s.IX)
 		s.PC++
 		s.core.MemWrite(offset, s.core.MemRead(s.PC))
 	},
 	// 0x39 : ADD IX, SP
-	0x39: func(s *Z80Type) {
+	0x39: func(s *Z80) {
 		s.doIxAdd(s.SP)
 	},
 	// 0x44 : LD B, IXH (Undocumented)
-	0x44: func(s *Z80Type) {
+	0x44: func(s *Z80) {
 		s.B = byte(s.IX >> 8)
 	},
 	// 0x45 : LD B, IXL (Undocumented)
-	0x45: func(s *Z80Type) {
+	0x45: func(s *Z80) {
 		s.B = byte(s.IX & 0x00ff)
 	},
 	// 0x46 : LD B, (IX+n)
-	0x46: func(s *Z80Type) {
+	0x46: func(s *Z80) {
 		s.B = s.core.MemRead(s.getOffset(s.IX))
 	},
 	// 0x4c : LD C, IXH (Undocumented)
-	0x4C: func(s *Z80Type) {
+	0x4C: func(s *Z80) {
 		s.C = byte(s.IX >> 8)
 	},
 	// 0x4d : LD C, IXL (Undocumented)
-	0x4D: func(s *Z80Type) {
+	0x4D: func(s *Z80) {
 		s.C = byte(s.IX & 0x00ff)
 	},
 	// 0x4e : LD C, (IX+n)
-	0x4E: func(s *Z80Type) {
+	0x4E: func(s *Z80) {
 		s.C = s.core.MemRead(s.getOffset(s.IX))
 	},
 	// 0x54 : LD D, IXH (Undocumented)
-	0x54: func(s *Z80Type) {
+	0x54: func(s *Z80) {
 		s.D = byte(s.IX >> 8)
 	},
 	// 0x55 : LD D, IXL (Undocumented)
-	0x55: func(s *Z80Type) {
+	0x55: func(s *Z80) {
 		s.D = byte(s.IX)
 	},
 	// 0x56 : LD D, (IX+n)
-	0x56: func(s *Z80Type) {
+	0x56: func(s *Z80) {
 		offset := s.getOffset(s.IX)
 		s.D = s.core.MemRead(offset)
 	},
 	// 0x5d : LD E, IXL (Undocumented)
-	0x5D: func(s *Z80Type) {
+	0x5D: func(s *Z80) {
 		s.E = byte(s.IX)
 	},
 	// 0x5e : LD E, (IX+n)
-	0x5E: func(s *Z80Type) {
+	0x5E: func(s *Z80) {
 		s.E = s.core.MemRead(s.getOffset(s.IX))
 	},
 	// 0x60 : LD IXH, B (Undocumented)
-	0x60: func(s *Z80Type) {
+	0x60: func(s *Z80) {
 		s.IX = uint16(s.B)<<8 | s.IX&0x00ff
 	},
 	// 0x61 : LD IXH, C (Undocumented)
-	0x61: func(s *Z80Type) {
+	0x61: func(s *Z80) {
 		s.IX = uint16(s.C)<<8 | s.IX&0x00ff
 	},
 	// 0x62 : LD IXH, D (Undocumented)
-	0x62: func(s *Z80Type) {
+	0x62: func(s *Z80) {
 		s.IX = uint16(s.D)<<8 | s.IX&0x00ff
 	},
 	// 0x63 : LD IXH, E (Undocumented)
-	0x63: func(s *Z80Type) {
+	0x63: func(s *Z80) {
 		s.IX = uint16(s.E)<<8 | s.IX&0x00ff
 	},
 	// 0x64 : LD IXH, IXH (Undocumented)
-	0x64: func(s *Z80Type) {
+	0x64: func(s *Z80) {
 		// NOP
 	},
 	// 0x65 : LD IXH, IXL (Undocumented)
-	0x65: func(s *Z80Type) {
+	0x65: func(s *Z80) {
 		s.IX = (s.IX << 8) | (s.IX & 0x00ff)
 	},
 	// 0x66 : LD H, (IX+n)
-	0x66: func(s *Z80Type) {
+	0x66: func(s *Z80) {
 		s.H = s.core.MemRead(s.getOffset(s.IX))
 	},
 	// 0x67 : LD IXH, A (Undocumented)
-	0x67: func(s *Z80Type) {
+	0x67: func(s *Z80) {
 		s.IX = (uint16(s.A) << 8) | (s.IX & 0x00ff)
 	},
 	// 0x68 : LD IXL, B (Undocumented)
-	0x68: func(s *Z80Type) {
+	0x68: func(s *Z80) {
 		s.IX = (s.IX & 0xff00) | uint16(s.B)
 	},
 	// 0x69 : LD IXL, C (Undocumented)
-	0x69: func(s *Z80Type) {
+	0x69: func(s *Z80) {
 		s.IX = (s.IX & 0xff00) | uint16(s.C)
 	},
 	// 0x6a : LD IXL, D (Undocumented)
-	0x6a: func(s *Z80Type) {
+	0x6a: func(s *Z80) {
 		s.IX = (s.IX & 0xff00) | uint16(s.D)
 	},
 	// 0x6b : LD IXL, E (Undocumented)
-	0x6b: func(s *Z80Type) {
+	0x6b: func(s *Z80) {
 		s.IX = (s.IX & 0xff00) | uint16(s.E)
 	},
 	// 0x6c : LD IXL, IXH (Undocumented)
-	0x6c: func(s *Z80Type) {
+	0x6c: func(s *Z80) {
 		s.IX = (s.IX >> 8) | (s.IX & 0xff00)
 	},
 	// 0x6d : LD IXL, IXL (Undocumented)
-	0x6d: func(s *Z80Type) {
+	0x6d: func(s *Z80) {
 		// NOP
 	},
 	// 0x6e : LD L, (IX+n)
-	0x6e: func(s *Z80Type) {
+	0x6e: func(s *Z80) {
 		s.L = s.core.MemRead(s.getOffset(s.IX))
 	},
 	// 0x6f : LD IXL, A (Undocumented)
-	0x6f: func(s *Z80Type) {
+	0x6f: func(s *Z80) {
 		s.IX = uint16(s.A) | (s.IX & 0xff00)
 	},
 	// 0x70 : LD (IX+n), B
-	0x70: func(s *Z80Type) {
+	0x70: func(s *Z80) {
 		s.core.MemWrite(s.getOffset(s.IX), s.B)
 	},
 	// 0x71 : LD (IX+n), C
-	0x71: func(s *Z80Type) {
+	0x71: func(s *Z80) {
 		s.core.MemWrite(s.getOffset(s.IX), s.C)
 	},
 	// 0x72 : LD (IX+n), D
-	0x72: func(s *Z80Type) {
+	0x72: func(s *Z80) {
 		s.core.MemWrite(s.getOffset(s.IX), s.D)
 	},
 	// 0x73 : LD (IX+n), E
-	0x73: func(s *Z80Type) {
+	0x73: func(s *Z80) {
 		s.core.MemWrite(s.getOffset(s.IX), s.E)
 	},
 	// 0x74 : LD (IX+n), H
-	0x74: func(s *Z80Type) {
+	0x74: func(s *Z80) {
 		s.core.MemWrite(s.getOffset(s.IX), s.H)
 	},
 	// 0x75 : LD (IX+n), L
-	0x75: func(s *Z80Type) {
+	0x75: func(s *Z80) {
 		s.core.MemWrite(s.getOffset(s.IX), s.L)
 	},
 	// 0x77 : LD (IX+n), A
-	0x77: func(s *Z80Type) {
+	0x77: func(s *Z80) {
 		s.core.MemWrite(s.getOffset(s.IX), s.A)
 	},
 	// 0x7c : LD A, IXH (Undocumented)
-	0x7C: func(s *Z80Type) {
+	0x7C: func(s *Z80) {
 		s.A = byte(s.IX >> 8)
 	},
 	// 0x7d : LD A, IXL (Undocumented)
-	0x7D: func(s *Z80Type) {
+	0x7D: func(s *Z80) {
 		s.A = byte(s.IX & 0x00ff)
 	},
 	// 0x7e : LD A, (IX+n)
-	0x7E: func(s *Z80Type) {
+	0x7E: func(s *Z80) {
 		s.A = s.core.MemRead(s.getOffset(s.IX))
 	},
 	// 0x84 : ADD A, IXH (Undocumented)
-	0x84: func(s *Z80Type) {
+	0x84: func(s *Z80) {
 		s.doAdd(byte(s.IX >> 8))
 	},
 	// 0x85 : ADD A, IXL (Undocumented)
-	0x85: func(s *Z80Type) {
+	0x85: func(s *Z80) {
 		s.doAdd(byte(s.IX))
 	},
 	// 0x86 : ADD A, (IX+n)
-	0x86: func(s *Z80Type) {
+	0x86: func(s *Z80) {
 		s.doAdd(s.core.MemRead(s.getOffset(s.IX)))
 	},
 	// 0x8c : ADC A, IXH (Undocumented)
-	0x8C: func(s *Z80Type) {
+	0x8C: func(s *Z80) {
 		s.doAdc(byte(s.IX >> 8))
 	},
 	// 0x8d : ADC A, IXL (Undocumented)
-	0x8D: func(s *Z80Type) {
+	0x8D: func(s *Z80) {
 		s.doAdc(byte(s.IX))
 	},
 	// 0x8e : ADC A, (IX+n)
-	0x8E: func(s *Z80Type) {
+	0x8E: func(s *Z80) {
 		s.doAdc(s.core.MemRead(s.getOffset(s.IX)))
 	},
 	// 0x94 : SUB IXH (Undocumented)
-	0x94: func(s *Z80Type) {
+	0x94: func(s *Z80) {
 		s.doSub(byte(s.IX >> 8))
 	},
 	// 0x95 : SUB IXL (Undocumented)
-	0x95: func(s *Z80Type) {
+	0x95: func(s *Z80) {
 		s.doSub(byte(s.IX))
 	},
 	// 0x96 : SUB A, (IX+n)
-	0x96: func(s *Z80Type) {
+	0x96: func(s *Z80) {
 		s.doSub(s.core.MemRead(s.getOffset(s.IX)))
 	},
 	// 0x9c : SBC IXH (Undocumented)
-	0x9C: func(s *Z80Type) {
+	0x9C: func(s *Z80) {
 		s.doSbc(byte(s.IX >> 8))
 	},
 	// 0x9d : SBC IXL (Undocumented)
-	0x9D: func(s *Z80Type) {
+	0x9D: func(s *Z80) {
 		s.doSbc(byte(s.IX))
 	},
 	// 0x9e : SBC A, (IX+n)
-	0x9E: func(s *Z80Type) {
+	0x9E: func(s *Z80) {
 		s.doSbc(s.core.MemRead(s.getOffset(s.IX)))
 	},
 	// 0xa4 : AND IXH (Undocumented)
-	0xA4: func(s *Z80Type) {
+	0xA4: func(s *Z80) {
 		s.doAnd(byte(s.IX >> 8))
 	},
 	// 0xa5 : AND IXL (Undocumented)
-	0xA5: func(s *Z80Type) {
+	0xA5: func(s *Z80) {
 		s.doAnd(byte(s.IX))
 	},
 	// 0xa6 : AND A, (IX+n)
-	0xA6: func(s *Z80Type) {
+	0xA6: func(s *Z80) {
 		s.doAnd(s.core.MemRead(s.getOffset(s.IX)))
 	},
 	// 0xac : XOR IXH (Undocumented)
-	0xAC: func(s *Z80Type) {
+	0xAC: func(s *Z80) {
 		s.doXor(byte(s.IX >> 8))
 	},
 	// 0xad : XOR IXL (Undocumented)
-	0xAD: func(s *Z80Type) {
+	0xAD: func(s *Z80) {
 		s.doXor(byte(s.IX))
 	},
 	// 0xae : XOR A, (IX+n)
-	0xAE: func(s *Z80Type) {
+	0xAE: func(s *Z80) {
 		s.doXor(s.core.MemRead(s.getOffset(s.IX)))
 	},
 	// 0xb4 : OR IXH (Undocumented)
-	0xB4: func(s *Z80Type) {
+	0xB4: func(s *Z80) {
 		s.doOr(byte(s.IX >> 8))
 	},
 	// 0xb5 : OR IXL (Undocumented)
-	0xB5: func(s *Z80Type) {
+	0xB5: func(s *Z80) {
 		s.doOr(byte(s.IX))
 	},
 	// 0xb6 : OR A, (IX+n)
-	0xB6: func(s *Z80Type) {
+	0xB6: func(s *Z80) {
 		s.doOr(s.core.MemRead(s.getOffset(s.IX)))
 	},
 	// 0xbc : CP IXH (Undocumented)
-	0xBC: func(s *Z80Type) {
+	0xBC: func(s *Z80) {
 		s.doCp(byte(s.IX >> 8))
 	},
 	// 0xbd : CP IXL (Undocumented)
-	0xBD: func(s *Z80Type) {
+	0xBD: func(s *Z80) {
 		s.doCp(byte(s.IX))
 	},
 	// 0xbe : CP A, (IX+n)
-	0xBE: func(s *Z80Type) {
+	0xBE: func(s *Z80) {
 		s.doCp(s.core.MemRead(s.getOffset(s.IX)))
 	},
 	// 0xcb : CB Prefix (IX bit instructions)
-	0xCB: func(s *Z80Type) {
+	0xCB: func(s *Z80) {
 		s.opcodeDDCB()
 	},
 	// 0xe1 : POP IX
-	0xE1: func(s *Z80Type) {
+	0xE1: func(s *Z80) {
 		s.IX = s.PopWord()
 	},
 	// 0xe3 : EX (SP), IX
-	0xE3: func(s *Z80Type) {
+	0xE3: func(s *Z80) {
 		ix := s.IX
 		s.IX = s.getWord(s.SP)
 		s.setWord(s.SP, ix)
 	},
 	// 0xe5 : PUSH IX
-	0xE5: func(s *Z80Type) {
+	0xE5: func(s *Z80) {
 		s.pushWord(s.IX)
 	},
 	// 0xe9 : JP (IX)
-	0xE9: func(s *Z80Type) {
+	0xE9: func(s *Z80) {
 		s.PC = s.IX - 1
 	},
 	// 0xf9 : LD SP, IX
-	0xf9: func(s *Z80Type) {
+	0xf9: func(s *Z80) {
 		s.SP = s.IX
 	},
 }
 
 // =====================================================
-func (z *Z80Type) getOffset(reg uint16) uint16 {
+func (z *Z80) getOffset(reg uint16) uint16 {
 	z.PC++
 	offset := z.core.MemRead(z.PC)
 	if offset < 0 {
@@ -366,7 +366,7 @@ func (z *Z80Type) getOffset(reg uint16) uint16 {
 	return reg
 }
 
-func (z *Z80Type) opcodeDD() {
+func (z *Z80) opcodeDD() {
 	z.incR()
 	z.PC++
 	opcode := z.core.M1MemRead(z.PC)
@@ -387,7 +387,7 @@ func (z *Z80Type) opcodeDD() {
 	}
 }
 
-func (z *Z80Type) opcodeDDCB() {
+func (z *Z80) opcodeDDCB() {
 
 	offset := z.getOffset(z.IX)
 	z.PC++
@@ -456,7 +456,7 @@ func (z *Z80Type) opcodeDDCB() {
 }
 
 // opcodeFD do same for IY as for IX (DD prefix)
-func (z *Z80Type) opcodeFD() {
+func (z *Z80) opcodeFD() {
 	z.incR()
 	z.PC++
 	opcode := z.core.M1MemRead(z.PC)
diff --git a/z80em/opcodeED.go b/z80/js/opcodeED.go
similarity index 70%
rename from z80em/opcodeED.go
rename to z80/js/opcodeED.go
index 7afbb13..5a4f865 100644
--- a/z80em/opcodeED.go
+++ b/z80/js/opcodeED.go
@@ -1,182 +1,182 @@
-package z80em
+package js
 
-var edInstructions = []func(s *Z80Type){
+var edInstructions = []func(s *Z80){
 	// 0x40 : IN B, (C)
-	0x40: func(s *Z80Type) {
+	0x40: func(s *Z80) {
 		s.B = s.doIn(s.bc())
 	},
 	// 0x41 : OUT (C), B
-	0x41: func(s *Z80Type) {
+	0x41: func(s *Z80) {
 		s.core.IOWrite(s.bc(), s.B)
 	},
 	// 0x42 : SBC HL, BC
-	0x42: func(s *Z80Type) {
+	0x42: func(s *Z80) {
 		s.doHlSbc(s.bc())
 	},
 	// 0x43 : LD (nn), BC
-	0x43: func(s *Z80Type) {
+	0x43: func(s *Z80) {
 		s.setWord(s.nextWord(), s.bc())
 	},
 	// 0x44 : NEG
-	0x44: func(s *Z80Type) {
+	0x44: func(s *Z80) {
 		s.doNeg()
 	},
 	// 0x45 : RETN
-	0x45: func(s *Z80Type) {
+	0x45: func(s *Z80) {
 		s.PC = s.PopWord() - 1
 		s.Iff1 = s.Iff2
 	},
 	// 0x46 : IM 0
-	0x46: func(s *Z80Type) {
+	0x46: func(s *Z80) {
 		s.IMode = 0
 	},
 	// 0x47 : LD I, A
-	0x47: func(s *Z80Type) {
+	0x47: func(s *Z80) {
 		s.I = s.A
 	},
 	// 0x48 : IN C, (C)
-	0x48: func(s *Z80Type) {
+	0x48: func(s *Z80) {
 		s.C = s.doIn(s.bc())
 	},
 	// 0x49 : OUT (C), C
-	0x49: func(s *Z80Type) {
+	0x49: func(s *Z80) {
 		s.core.IOWrite(s.bc(), s.C)
 	},
 	// 0x4a : ADC HL, BC
-	0x4A: func(s *Z80Type) {
+	0x4A: func(s *Z80) {
 		s.doHlAdc(s.bc())
 	},
 	// 0x4b : LD BC, (nn)
-	0x4B: func(s *Z80Type) {
+	0x4B: func(s *Z80) {
 		s.setBc(s.getWord(s.nextWord()))
 	},
 	// 0x4c : NEG (Undocumented)
-	0x4C: func(s *Z80Type) {
+	0x4C: func(s *Z80) {
 		s.doNeg()
 	},
 	// 0x4d : RETI
-	0x4D: func(s *Z80Type) {
+	0x4D: func(s *Z80) {
 		s.PC = s.PopWord() - 1
 	},
 	// 0x4e : IM 0 (Undocumented)
-	0x4E: func(s *Z80Type) {
+	0x4E: func(s *Z80) {
 		s.IMode = 0
 	},
 	// 0x4f : LD R, A
-	0x4F: func(s *Z80Type) {
+	0x4F: func(s *Z80) {
 		s.R = s.A
 	},
 	// 0x50 : IN D, (C)
-	0x50: func(s *Z80Type) {
+	0x50: func(s *Z80) {
 		s.D = s.doIn(s.bc())
 	},
 	// 0x51 : OUT (C), D
-	0x51: func(s *Z80Type) {
+	0x51: func(s *Z80) {
 		s.core.IOWrite(s.bc(), s.D)
 	},
 	// 0x52 : SBC HL, DE
-	0x52: func(s *Z80Type) {
+	0x52: func(s *Z80) {
 		s.doHlSbc(s.de())
 	},
 	// 0x53 : LD (nn), DE
-	0x53: func(s *Z80Type) {
+	0x53: func(s *Z80) {
 		s.setWord(s.nextWord(), s.de())
 	},
 	// 0x54 : NEG (Undocumented)
-	0x54: func(s *Z80Type) {
+	0x54: func(s *Z80) {
 		s.doNeg()
 	},
 	// 0x55 : RETN
-	0x55: func(s *Z80Type) {
+	0x55: func(s *Z80) {
 		s.PC = s.PopWord() - 1
 		s.Iff1 = s.Iff2
 	},
 	// 0x56 : IM 1
-	0x56: func(s *Z80Type) {
+	0x56: func(s *Z80) {
 		s.IMode = 1
 	},
 	// 0x57 : LD A, I
-	0x57: func(s *Z80Type) {
+	0x57: func(s *Z80) {
 		s.A = s.I
 		s.Flags.S = s.A&0x80 != 0
 		s.Flags.Z = s.A == 0
 		s.Flags.H = false
-		s.Flags.P = s.Iff2 != 0
+		s.Flags.P = s.Iff2
 		s.Flags.N = false
 		s.updateXYFlags(s.A)
 
 	},
 	// 0x58 : IN E, (C)
-	0x58: func(s *Z80Type) {
+	0x58: func(s *Z80) {
 		s.E = s.doIn(s.bc())
 	},
 	// 0x59 : OUT (C), E
-	0x59: func(s *Z80Type) {
+	0x59: func(s *Z80) {
 		s.core.IOWrite(s.bc(), s.E)
 	},
 	// 0x5a : ADC HL, DE
-	0x5A: func(s *Z80Type) {
+	0x5A: func(s *Z80) {
 		s.doHlAdc(s.de())
 	},
 	// 0x5b : LD DE, (nn)
-	0x5B: func(s *Z80Type) {
+	0x5B: func(s *Z80) {
 		s.setDe(s.getWord(s.nextWord()))
 	},
 	// 0x5c : NEG (Undocumented)
-	0x5C: func(s *Z80Type) {
+	0x5C: func(s *Z80) {
 		s.doNeg()
 	},
 	// 0x5d : RETN
-	0x5D: func(s *Z80Type) {
+	0x5D: func(s *Z80) {
 		s.PC = s.PopWord() - 1
 		s.Iff1 = s.Iff2
 	},
 	// 0x5e : IM 2
-	0x5E: func(s *Z80Type) {
+	0x5E: func(s *Z80) {
 		s.IMode = 2
 	},
 	// 0x5f : LD A, R
-	0x5F: func(s *Z80Type) {
+	0x5F: func(s *Z80) {
 		s.A = s.R
 		s.Flags.S = s.A&0x80 != 0
 		s.Flags.Z = s.A == 0
 		s.Flags.H = false
-		s.Flags.P = s.Iff2 != 0
+		s.Flags.P = s.Iff2
 		s.Flags.N = false
 		s.updateXYFlags(s.A)
 
 	},
 	// 0x60 : IN H, (C)
-	0x60: func(s *Z80Type) {
+	0x60: func(s *Z80) {
 		s.H = s.doIn(s.bc())
 	},
 	// 0x61 : OUT (C), H
-	0x61: func(s *Z80Type) {
+	0x61: func(s *Z80) {
 		s.core.IOWrite(s.bc(), s.H)
 	},
 	// 0x62 : SBC HL, HL
-	0x62: func(s *Z80Type) {
+	0x62: func(s *Z80) {
 		s.doHlSbc(s.hl())
 	},
 	// 0x63 : LD (nn), HL (Undocumented)
-	0x63: func(s *Z80Type) {
+	0x63: func(s *Z80) {
 		s.setWord(s.nextWord(), s.hl())
 	},
 	// 0x64 : NEG (Undocumented)
-	0x64: func(s *Z80Type) {
+	0x64: func(s *Z80) {
 		s.doNeg()
 	},
 	// 0x65 : RETN
-	0x65: func(s *Z80Type) {
+	0x65: func(s *Z80) {
 		s.PC = s.PopWord() - 1
 		s.Iff1 = s.Iff2
 	},
 	// 0x66 : IM 0
-	0x66: func(s *Z80Type) {
+	0x66: func(s *Z80) {
 		s.IMode = 0
 	},
 	// 0x67 : RRD
-	0x67: func(s *Z80Type) {
+	0x67: func(s *Z80) {
 		hlValue := s.core.M1MemRead(s.hl())
 		temp1 := hlValue & 0x0f
 		temp2 := s.A & 0x0f
@@ -192,36 +192,36 @@ var edInstructions = []func(s *Z80Type){
 
 	},
 	// 0x68 : IN L, (C)
-	0x68: func(s *Z80Type) {
+	0x68: func(s *Z80) {
 		s.L = s.doIn(s.bc())
 	},
 	// 0x69 : OUT (C), L
-	0x69: func(s *Z80Type) {
+	0x69: func(s *Z80) {
 		s.core.IOWrite(s.bc(), s.L)
 	},
 	// 0x6a : ADC HL, HL
-	0x6A: func(s *Z80Type) {
+	0x6A: func(s *Z80) {
 		s.doHlAdc(s.hl())
 	},
 	// 0x6b : LD HL, (nn) (Undocumented)
-	0x6B: func(s *Z80Type) {
+	0x6B: func(s *Z80) {
 		s.setHl(s.getWord(s.nextWord()))
 	},
 	// 0x6C : NEG (Undocumented)
-	0x6C: func(s *Z80Type) {
+	0x6C: func(s *Z80) {
 		s.doNeg()
 	},
 	// 0x6D : RETN
-	0x6D: func(s *Z80Type) {
+	0x6D: func(s *Z80) {
 		s.PC = s.PopWord() - 1
 		s.Iff1 = s.Iff2
 	},
 	// 0x6E : IM 0
-	0x6E: func(s *Z80Type) {
+	0x6E: func(s *Z80) {
 		s.IMode = 0
 	},
 	// 0x6f : RLD
-	0x6F: func(s *Z80Type) {
+	0x6F: func(s *Z80) {
 		hlValue := s.core.MemRead(s.hl())
 		temp1 := hlValue & 0xf0
 		temp2 := s.A & 0x0f
@@ -237,97 +237,97 @@ var edInstructions = []func(s *Z80Type){
 		s.updateXYFlags(s.A)
 	},
 	// 0x70 : INF
-	0x70: func(s *Z80Type) {
+	0x70: func(s *Z80) {
 		s.doIn(s.bc())
 	},
 	// 0x71 : OUT (C), 0 (Undocumented)
-	0x71: func(s *Z80Type) {
+	0x71: func(s *Z80) {
 		s.core.IOWrite(s.bc(), 0)
 	},
 	// 0x72 : SBC HL, SP
-	0x72: func(s *Z80Type) {
+	0x72: func(s *Z80) {
 		s.doHlSbc(s.SP)
 	},
 	// 0x73 : LD (nn), SP
-	0x73: func(s *Z80Type) {
+	0x73: func(s *Z80) {
 		s.setWord(s.nextWord(), s.SP)
 	},
 	// 0x74 : NEG (Undocumented)
-	0x74: func(s *Z80Type) {
+	0x74: func(s *Z80) {
 		s.doNeg()
 	},
 	// 0x75 : RETN
-	0x75: func(s *Z80Type) {
+	0x75: func(s *Z80) {
 		s.PC = s.PopWord() - 1
 		s.Iff1 = s.Iff2
 	},
 	// 0x76 : IM 1
-	0x76: func(s *Z80Type) {
+	0x76: func(s *Z80) {
 		s.IMode = 1
 	},
 	// 0x78 : IN A, (C)
-	0x78: func(s *Z80Type) {
+	0x78: func(s *Z80) {
 		s.A = s.core.IORead(s.bc())
 	},
 	// 0x79 : OUT (C), A
-	0x79: func(s *Z80Type) {
+	0x79: func(s *Z80) {
 		s.core.IOWrite(s.bc(), s.A)
 	},
 	// 0x7a : ADC HL, SP
-	0x7A: func(s *Z80Type) {
+	0x7A: func(s *Z80) {
 		s.doHlAdc(s.SP)
 	},
 	// 0x7b : LD SP, (nn)
-	0x7B: func(s *Z80Type) {
+	0x7B: func(s *Z80) {
 		s.SP = s.getWord(s.nextWord())
 	},
 	// 0x7c : NEG (Undocumented)
-	0x7C: func(s *Z80Type) {
+	0x7C: func(s *Z80) {
 		s.doNeg()
 	},
 	// 0x7d : RETN
-	0x7D: func(s *Z80Type) {
+	0x7D: func(s *Z80) {
 		s.PC = s.PopWord() - 1
 		s.Iff1 = s.Iff2
 	},
 	// 0x7e : IM 2
-	0x7E: func(s *Z80Type) {
+	0x7E: func(s *Z80) {
 		s.IMode = 2
 	},
 	// 0xa0 : LDI
-	0xA0: func(s *Z80Type) {
+	0xA0: func(s *Z80) {
 		s.doLdi()
 	},
 	// 0xa1 : CPI
-	0xA1: func(s *Z80Type) {
+	0xA1: func(s *Z80) {
 		s.doCpi()
 	},
 	// 0xa2 : INI
-	0xA2: func(s *Z80Type) {
+	0xA2: func(s *Z80) {
 		s.doIni()
 	},
 	// 0xa3 : OUTI
-	0xA3: func(s *Z80Type) {
+	0xA3: func(s *Z80) {
 		s.doOuti()
 	},
 	// 0xa8 : LDD
-	0xA8: func(s *Z80Type) {
+	0xA8: func(s *Z80) {
 		s.doLdd()
 	},
 	// 0xa9 : CPD
-	0xA9: func(s *Z80Type) {
+	0xA9: func(s *Z80) {
 		s.doCpd()
 	},
 	// 0xaa : IND
-	0xAA: func(s *Z80Type) {
+	0xAA: func(s *Z80) {
 		s.doInd()
 	},
 	// 0xab : OUTD
-	0xAB: func(s *Z80Type) {
+	0xAB: func(s *Z80) {
 		s.doOutd()
 	},
 	// 0xb0 : LDIR
-	0xB0: func(s *Z80Type) {
+	0xB0: func(s *Z80) {
 		s.doLdi()
 		if (s.B | s.C) != 0 {
 			s.CycleCounter += 5
@@ -335,7 +335,7 @@ var edInstructions = []func(s *Z80Type){
 		}
 	},
 	// 0xb1 : CPIR
-	0xB1: func(s *Z80Type) {
+	0xB1: func(s *Z80) {
 		s.doCpi()
 		if !s.Flags.Z && (s.B|s.C) != 0 {
 			s.CycleCounter += 5
@@ -343,7 +343,7 @@ var edInstructions = []func(s *Z80Type){
 		}
 	},
 	// 0xb2 : INIR
-	0xB2: func(s *Z80Type) {
+	0xB2: func(s *Z80) {
 		s.doIni()
 		if s.B != 0 {
 			s.CycleCounter += 5
@@ -351,7 +351,7 @@ var edInstructions = []func(s *Z80Type){
 		}
 	},
 	// 0xb3 : OTIR
-	0xB3: func(s *Z80Type) {
+	0xB3: func(s *Z80) {
 		s.doOuti()
 		if s.B != 0 {
 			s.CycleCounter += 5
@@ -359,7 +359,7 @@ var edInstructions = []func(s *Z80Type){
 		}
 	},
 	// 0xb8 : LDDR
-	0xB8: func(s *Z80Type) {
+	0xB8: func(s *Z80) {
 		s.doLdd()
 		if (s.B | s.C) != 0 {
 			s.CycleCounter += 5
@@ -367,7 +367,7 @@ var edInstructions = []func(s *Z80Type){
 		}
 	},
 	// 0xb9 : CPDR
-	0xB9: func(s *Z80Type) {
+	0xB9: func(s *Z80) {
 		s.doCpd()
 		if !s.Flags.Z && (s.B|s.C) != 0 {
 			s.CycleCounter += 5
@@ -375,7 +375,7 @@ var edInstructions = []func(s *Z80Type){
 		}
 	},
 	// 0xba : INDR
-	0xBA: func(s *Z80Type) {
+	0xBA: func(s *Z80) {
 		s.doInd()
 		if s.B != 0 {
 			s.CycleCounter += 5
@@ -383,7 +383,7 @@ var edInstructions = []func(s *Z80Type){
 		}
 	},
 	// 0xbb : OTDR
-	0xBB: func(s *Z80Type) {
+	0xBB: func(s *Z80) {
 		s.doOutd()
 		if s.B != 0 {
 			s.CycleCounter += 5
@@ -392,7 +392,7 @@ var edInstructions = []func(s *Z80Type){
 	},
 }
 
-func (z *Z80Type) opcodeED() {
+func (z *Z80) opcodeED() {
 	z.incR()
 	z.PC++