Sprinter/mame
2
0
Fork 0
mirror of https://github.com/holub/mame synced 2025-04-21 07:52:35 +03:00
Code Issues Actions 1 Packages Projects Releases Wiki Activity

arm7: STM decrementing mode actually writes in incrementing mode on real h/w. Used heavily by GBA "Classic NES" carts. [R. Belmont, endrift]

Browse Source
This commit is contained in:
arbee 2015-03-25 19:17:48 -04:00
parent e3b280999c
commit c5e6aaaa71
1 changed files with 19 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
src/emu/cpu/arm7/arm7ops.c
View File

@ -253,12 +253,25 @@ int arm7_cpu_device::storeInc(UINT32 pat, UINT32 rbv, int mode)
} /* storeInc */
// classic CV: 3005aa0 does the DMA thing
int arm7_cpu_device::storeDec(UINT32 pat, UINT32 rbv, int mode)
{
int i, result;
int i, result = 0, cnt;
result = 0;
// pre-count the # of registers doing DMA
for (i = 15; i >= 0; i--)
{
if ((pat >> i) & 1)
{
result++;
// starting address
rbv -= 4;
}
}
cnt = 0;
for (i = 0; i <= 15; i++)
{
if ((pat >> i) & 1)
{
@ -266,8 +279,8 @@ int arm7_cpu_device::storeDec(UINT32 pat, UINT32 rbv, int mode)
if (i == 15) /* R15 is plus 12 from address of STM */
LOG(("%08x: StoreDec on R15\n", R15));
#endif
WRITE32(rbv -= 4, GET_MODE_REGISTER(mode, i));
result++;
WRITE32(rbv + (cnt * 4), GET_MODE_REGISTER(mode, i));
cnt++;
}
}
return result;
@ -1421,7 +1434,7 @@ void arm7_cpu_device::HandleMemBlock(UINT32 insn)
} /* Loading */
else
{
/* Storing */
/* Storing - STM */
if (insn & (1 << eR15))
{
#if ARM7_DEBUG_CORE
@ -1461,7 +1474,7 @@ void arm7_cpu_device::HandleMemBlock(UINT32 insn)
}
else
{
/* Decrementing */
/* Decrementing - but real CPU writes in incrementing order */
if (!(insn & INSN_BDT_P))
{
rbp = rbp - (-4);