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Arisotura
2021-05-11 22:36:42 +02:00
parent 3b72fd84a3
commit 9e7463528e
1 changed files with 20 additions and 15 deletions
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27
src/NDS.cpp
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@ -1245,31 +1245,36 @@ void SetGBASlotTimings()
const int ntimings[4] = {10, 8, 6, 18};
const u16 openbus[4] = {0xFE08, 0x0000, 0x0000, 0xFFFF};
u16 curcnt;
int ramN, romN, romS;
u16 curcpu = (ExMemCnt[0] >> 7) & 0x1;
u16 curcnt = ExMemCnt[curcpu];
int ramN = ntimings[curcnt & 0x3];
int romN = ntimings[(curcnt>>2) & 0x3];
int romS = (curcnt & 0x10) ? 4 : 6;
curcnt = ExMemCnt[0];
ramN = ntimings[curcnt & 0x3];
romN = ntimings[(curcnt>>2) & 0x3];
romS = (curcnt & 0x10) ? 4 : 6;
// GBA slot timings only apply on the selected side
if (curcpu == 0)
{
SetARM9RegionTimings(0x08000000, 0x0A000000, 16, romN + 3, romS);
SetARM9RegionTimings(0x0A000000, 0x0B000000, 8, ramN + 3, ramN);
curcnt = ExMemCnt[1];
ramN = ntimings[curcnt & 0x3];
romN = ntimings[(curcnt>>2) & 0x3];
romS = (curcnt & 0x10) ? 4 : 6;
SetARM7RegionTimings(0x08000000, 0x0A000000, 32, 1, 1);
SetARM7RegionTimings(0x0A000000, 0x0B000000, 32, 1, 1);
}
else
{
SetARM9RegionTimings(0x08000000, 0x0A000000, 32, 1, 1);
SetARM9RegionTimings(0x0A000000, 0x0B000000, 32, 1, 1);
SetARM7RegionTimings(0x08000000, 0x0A000000, 16, romN, romS);
SetARM7RegionTimings(0x0A000000, 0x0B000000, 8, ramN, ramN);
}
// this open-bus implementation is a rough way of simulating the way values
// lingering on the bus decay after a while, which is visible at higher waitstates
// for example, the Cartridge Construction Kit relies on this to determine that
// the GBA slot is empty
curcnt = ExMemCnt[(ExMemCnt[0]>>7) & 0x1];
GBACart::SetOpenBusDecay(openbus[(curcnt>>2) & 0x3]);
}