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mcs48: remove todo note about EN/DIS I opcode not incrementing the timer, doc is wrong, and add another note
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@ -1,6 +1,6 @@
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// license:BSD-3-Clause
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// copyright-holders:Dan Boris, Mirko Buffoni, Aaron Giles, Couriersud
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/***************************************************************************
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/*******************************************************************************
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Intel MCS-48/UPI-41 Portable Emulator
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@ -10,13 +10,42 @@
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TODO:
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- add CMOS devices, 1 new opcode (01 IDL)
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- add special 8022 opcodes (RAD, SEL AN0, SEL AN1, RETI)
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- according to the user manual, some opcodes(dis/enable timer/interrupt)
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don't increment the timer, does it affect the prescaler too?
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Most likely, timer input (prescaler overflow or T1 edge) still occurs,
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just that m_timer increment is delayed 1 opcode.
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- IRQ timing is hacked due to WY-100 needing to take JNI branch before servicing interrupt
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- IRQ and/or timer increment timing is wrong? See test below. After IRQ,
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A = 0x20 on MAME, A = 0x22 on the real 8048 as tested by bataais.
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****************************************************************************
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stop tcnt
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mov a,0xff
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mov t,a
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inc a
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en tcnti
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strt t
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inc a
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inc a
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inc a
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(etc.)
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With the following test, on MAME, A = 0xff after 30 NOPs, A = 0 after 31
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NOPs. On the real 8048, A = 0xff after 31 NOPs, A = 0 after 32 NOPs.
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It can mean that STRT T has a 1 cycle delay, or simply that MOV A,T gets
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the timer value pre-increment.
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stop tcnt
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mov a,0xff
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mov t,a
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strt t
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nop
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nop
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nop
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(etc.)
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mov a,t
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- IRQ timing is hacked due to WY-100 needing to take JNI branch before
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servicing interrupt (see m_irq_polled), probably related to note above?
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********************************************************************************
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Note that the default internal divisor for this chip is by 3 and
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then again by 5, or by 15 total.
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@ -41,7 +70,7 @@
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8040 256 0 27 (external ROM)
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8050 256 4k 27 (ROM)
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****************************************************************************
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********************************************************************************
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UPI-41/42 chips are MCS-48 derived, with some opcode changes:
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@ -78,16 +107,16 @@
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8742 128 2k (EPROM)
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8742AH 256 2k (EPROM)
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***************************************************************************/
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*******************************************************************************/
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#include "emu.h"
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#include "mcs48.h"
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#include "mcs48dsm.h"
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/***************************************************************************
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/*******************************************************************************
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CONSTANTS
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***************************************************************************/
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*******************************************************************************/
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// timer/counter enable bits
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#define TIMER_ENABLED 0x01
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@ -121,9 +150,9 @@
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#define I8048_FEATURE (MB_FEATURE | EXT_BUS_FEATURE)
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/***************************************************************************
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/*******************************************************************************
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MACROS
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***************************************************************************/
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*******************************************************************************/
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// r0-r7 map to memory via the regptr
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#define R0 m_regptr[0]
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@ -136,9 +165,9 @@
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#define R7 m_regptr[7]
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/***************************************************************************
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/*******************************************************************************
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DEVICE TYPES
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***************************************************************************/
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*******************************************************************************/
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DEFINE_DEVICE_TYPE(I8021, i8021_device, "i8021", "Intel 8021")
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DEFINE_DEVICE_TYPE(I8022, i8022_device, "i8022", "Intel 8022")
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@ -166,9 +195,9 @@ DEFINE_DEVICE_TYPE(UPD7751, upd7751_device, "upd7751", "NEC uPD7751")
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DEFINE_DEVICE_TYPE(M58715, m58715_device, "m58715", "Mitsubishi M58715")
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/***************************************************************************
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/*******************************************************************************
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CONSTRUCTOR
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***************************************************************************/
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*******************************************************************************/
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mcs48_cpu_device::mcs48_cpu_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, u32 clock, int rom_size, int ram_size, u8 feature_mask, const mcs48_cpu_device::mcs48_ophandler *opcode_table)
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: cpu_device(mconfig, type, tag, owner, clock)
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@ -340,9 +369,9 @@ std::unique_ptr<util::disasm_interface> mcs48_cpu_device::create_disassembler()
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}
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/***************************************************************************
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/*******************************************************************************
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ADDRESS MAPS
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***************************************************************************/
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*******************************************************************************/
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void mcs48_cpu_device::program_map(address_map &map)
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{
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@ -364,9 +393,9 @@ void mcs48_cpu_device::data_map(address_map &map)
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}
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/***************************************************************************
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/*******************************************************************************
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INLINE FUNCTIONS
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***************************************************************************/
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*******************************************************************************/
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/*-------------------------------------------------
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opcode_fetch - fetch an opcode byte
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@ -588,9 +617,9 @@ void mcs48_cpu_device::expander_operation(expander_op operation, u8 port)
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/***************************************************************************
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/*******************************************************************************
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OPCODE HANDLERS
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***************************************************************************/
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*******************************************************************************/
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#define OPHANDLER(_name) void mcs48_cpu_device::_name()
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@ -598,7 +627,7 @@ void mcs48_cpu_device::expander_operation(expander_op operation, u8 port)
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OPHANDLER( illegal )
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{
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burn_cycles(1);
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logerror("MCS-48 PC:%04X - Illegal opcode = %02x\n", m_prevpc, program_r(m_prevpc));
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logerror("Illegal opcode = %02x @ %04X\n", program_r(m_prevpc), m_prevpc);
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}
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OPHANDLER( add_a_r0 ) { burn_cycles(1); execute_add(R0); }
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@ -873,7 +902,6 @@ OPHANDLER( out_dbb_a )
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port_w(2, m_p2 |= P2_OBF);
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}
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OPHANDLER( ret ) { burn_cycles(2); pull_pc(); }
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OPHANDLER( retr )
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{
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@ -937,9 +965,9 @@ OPHANDLER( xrl_a_n ) { burn_cycles(2); m_a ^= argument_fetch(); }
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/***************************************************************************
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/*******************************************************************************
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OPCODE TABLES
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***************************************************************************/
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*******************************************************************************/
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#define OP(_a) &mcs48_cpu_device::_a
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@ -1089,9 +1117,9 @@ const mcs48_cpu_device::mcs48_ophandler mcs48_cpu_device::s_i8022_opcodes[256] =
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/***************************************************************************
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/*******************************************************************************
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INITIALIZATION/RESET
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***************************************************************************/
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*******************************************************************************/
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void mcs48_cpu_device::device_config_complete()
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{
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@ -1244,9 +1272,9 @@ void mcs48_cpu_device::device_reset()
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}
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/***************************************************************************
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/*******************************************************************************
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EXECUTION
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***************************************************************************/
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*******************************************************************************/
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/*-------------------------------------------------
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check_irqs - check for and process IRQs
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@ -1374,9 +1402,9 @@ void mcs48_cpu_device::execute_run()
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/***************************************************************************
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/*******************************************************************************
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DATA ACCESS HELPERS
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***************************************************************************/
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*******************************************************************************/
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/*-------------------------------------------------
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upi41_master_r - master CPU data/status
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@ -1429,9 +1457,9 @@ void upi41_cpu_device::upi41_master_w(offs_t offset, u8 data)
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}
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/***************************************************************************
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/*******************************************************************************
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GENERAL CONTEXT ACCESS
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***************************************************************************/
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*******************************************************************************/
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/*-------------------------------------------------
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mcs48_import_state - import state from the
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