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It seems that indirect writes decrement the stack pointer BEFORE reading memory.

This commit is contained in:
brandman211 2012-07-28 17:06:06 +00:00
parent 1fb7d9a8a6
commit 188e5662ca
1 changed files with 13 additions and 19 deletions
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32
BizHawk.Emulation/CPUs/CP1610/Execute.cs
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@ -1169,7 +1169,7 @@ namespace BizHawk.Emulation.CPUs.CP1610
mem = (byte)((opcode >> 3) & 0x7);
src = (byte)(opcode & 0x7);
WriteMemory(Register[mem], Register[src]);
// Auto-increment.
// Auto-increment the memory register if it does so on read.
if (mem >= 0x4)
Register[mem]++;
PendingCycles -= 9; TotalExecutedCycles += 9;
@ -1243,6 +1243,9 @@ namespace BizHawk.Emulation.CPUs.CP1610
case 0x2BF:
mem = (byte)((opcode >> 3) & 0x7);
dest = (byte)(opcode & 0x7);
// Auto-decrement the stack pointer if it's the memory register.
if (mem == 0x6)
RegisterSP--;
if (!FlagD)
{
Register[dest] = ReadMemory(Register[mem]);
@ -1262,15 +1265,9 @@ namespace BizHawk.Emulation.CPUs.CP1610
Register[dest] |= (ushort)(ReadMemory(Register[mem]) & 0xFF);
PendingCycles -= 10; TotalExecutedCycles += 10;
}
if (mem >= 0x4)
{
if (mem == 0x6)
// Auto-decrement.
Register[mem]--;
else
// Auto-increment.
Register[mem]++;
}
// Auto-increment the memory register if it does so on write.
if (mem >= 0x4 && mem != 0x6)
Register[mem]++;
break;
// ADD
case 0x2C0:
@ -1341,6 +1338,9 @@ namespace BizHawk.Emulation.CPUs.CP1610
case 0x2FF:
mem = (byte)((opcode >> 3) & 0x7);
dest = (byte)(opcode & 0x7);
// Auto-decrement the stack pointer if it's the memory register.
if (mem == 0x6)
RegisterSP--;
if (!FlagD)
{
mem_read = ReadMemory(Register[mem]);
@ -1360,15 +1360,9 @@ namespace BizHawk.Emulation.CPUs.CP1610
mem_read |= (ushort)(ReadMemory(Register[mem]) & 0xFF);
PendingCycles -= 10; TotalExecutedCycles += 10;
}
if (mem >= 0x4)
{
if (mem == 0x6)
// Auto-decrement.
Register[mem]--;
else
// Auto-increment.
Register[mem]++;
}
// Auto-increment the memory register if it does so on write.
if (mem >= 0x4 && mem != 0x6)
Register[mem]++;
dest_value = Register[dest];
result = mem_read + dest_value;
Calc_FlagC(result);