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ARM7: Fix an LDM base register write-back bug. [Tim Schuerewegen]

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This commit is contained in:
R. Belmont 2011-01-30 00:41:11 +00:00
parent 695f1ae54e
commit eef37b5e13
1 changed files with 11 additions and 2 deletions
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11
src/emu/cpu/arm7/arm7core.c
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@ -1843,8 +1843,13 @@ static void HandleMemBlock(arm_state *cpustate, UINT32 insn)
if (rb == 15)
LOG(("%08x: Illegal LDRM writeback to r15\n", R15));
#endif
// "A LDM will always overwrite the updated base if the base is in the list." (also for a user bank transfer?)
// GBA "V-Rally 3" expects R0 not to be overwritten with the updated base value [BP 8077B0C]
if (((insn >> rb) & 1) == 0)
{
SET_REGISTER(cpustate, rb, GET_REGISTER(cpustate, rb) + result * 4);
}
}
// R15 included? (NOTE: CPSR restore must occur LAST otherwise wrong registers restored!)
if ((insn & 0x8000) && (cpustate->pendingAbtD == 0)) {
@ -1896,7 +1901,11 @@ static void HandleMemBlock(arm_state *cpustate, UINT32 insn)
{
if (rb == 0xf)
LOG(("%08x: Illegal LDRM writeback to r15\n", R15));
SET_REGISTER(cpustate, rb, GET_REGISTER(cpustate, rb)-result*4);
// "A LDM will always overwrite the updated base if the base is in the list." (also for a user bank transfer?)
if (((insn >> rb) & 1) == 0)
{
SET_REGISTER(cpustate, rb, GET_REGISTER(cpustate, rb) - result * 4);
}
}
// R15 included? (NOTE: CPSR restore must occur LAST otherwise wrong registers restored!)