From fa74509843dbf4b4771c276b476b518a6147a78c Mon Sep 17 00:00:00 2001
From: hap <happppp@users.noreply.github.com>
Date: Tue, 9 May 2017 22:59:07 +0200
Subject: [PATCH] sm510d: get rid of half-broken param fetch (nw)

---
 src/devices/cpu/sm510/sm510.h     |  4 ++--
 src/devices/cpu/sm510/sm510d.cpp  | 13 +++++++------
 src/devices/cpu/sm510/sm590op.cpp |  4 ++--
 3 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/src/devices/cpu/sm510/sm510.h b/src/devices/cpu/sm510/sm510.h
index bb0cd2de905..cfa1eab9661 100644
--- a/src/devices/cpu/sm510/sm510.h
+++ b/src/devices/cpu/sm510/sm510.h
@@ -148,7 +148,7 @@ protected:
 
 	// device_disasm_interface overrides
 	virtual u32 disasm_min_opcode_bytes() const override { return 1; }
-	virtual u32 disasm_max_opcode_bytes() const override { return 0x40; } // actually 2, but debugger doesn't like non-linear pc
+	virtual u32 disasm_max_opcode_bytes() const override { return 2; }
 
 	address_space_config m_program_config;
 	address_space_config m_data_config;
@@ -164,7 +164,7 @@ protected:
 	u16 m_op, m_prev_op;
 	u8 m_param;
 	int m_stack_levels;
-	u16 m_stack[2];
+	u16 m_stack[4]; // max 4
 	int m_icount;
 
 	u8 m_acc;
diff --git a/src/devices/cpu/sm510/sm510d.cpp b/src/devices/cpu/sm510/sm510d.cpp
index 4fe950ee29b..46b65ddcb0f 100644
--- a/src/devices/cpu/sm510/sm510d.cpp
+++ b/src/devices/cpu/sm510/sm510d.cpp
@@ -2,7 +2,7 @@
 // copyright-holders:hap, Jonathan Gevaryahu
 /*
 
-  Sharp SM510/SM500 MCU family disassembler
+  Sharp SM5xx MCU family disassembler
 
 */
 
@@ -175,7 +175,6 @@ static offs_t sm510_common_disasm(const u8 *lut_mnemonic, const u8 *lut_extended
 	// get raw opcode
 	u8 op = oprom[0];
 	u8 instr = lut_mnemonic[op];
-	s8 s_next_pc = ((pclen==6)?s_next_pc_6[pc & 0x3f]:s_next_pc_7[pc & 0x7f]);
 	int len = 1;
 
 	int bits = s_bits[instr];
@@ -183,9 +182,8 @@ static offs_t sm510_common_disasm(const u8 *lut_mnemonic, const u8 *lut_extended
 	u16 param = mask;
 	if (bits >= 8)
 	{
-		// note: disasm view shows correct parameter, but raw view does not
-		// note2: oprom array negative index doesn't work either :(
-		param = oprom[s_next_pc];
+		// note: doesn't work with lfsr pc
+		param = oprom[1];
 		len++;
 	}
 
@@ -218,7 +216,10 @@ static offs_t sm510_common_disasm(const u8 *lut_mnemonic, const u8 *lut_extended
 
 		// show param offset
 		if (bits >= 8)
-			util::stream_format(stream, " [$%03X]", pc + s_next_pc);
+		{
+			s8 next_pc_delta = ((pclen == 6) ? s_next_pc_6[pc & 0x3f] : s_next_pc_7[pc & 0x7f]);
+			util::stream_format(stream, " [$%03X]", pc + next_pc_delta);
+		}
 	}
 
 	return len | s_flags[instr] | DASMFLAG_SUPPORTED;
diff --git a/src/devices/cpu/sm510/sm590op.cpp b/src/devices/cpu/sm510/sm590op.cpp
index ec6a6657f60..3d116a436fd 100644
--- a/src/devices/cpu/sm510/sm590op.cpp
+++ b/src/devices/cpu/sm510/sm590op.cpp
@@ -75,7 +75,7 @@ void sm590_device::op_debm()
 void sm590_device::op_tc()
 {
 	// TC: skip next if carry
-	m_skip = m_c;
+	m_skip = bool(m_c);
 }
 
 void sm590_device::op_rta()
@@ -108,7 +108,7 @@ void sm590_device::op_ads()
 {
 	// ADS: add RAM to ACC, skip next on carry
 	m_acc += ram_r();
-	m_skip = (m_c == 1);
+	m_skip = bool(m_acc & 0x10);
 	m_acc &= 0xf;
 }