piwalker/melonDS
1
0
Fork 0
mirror of https://github.com/melonDS-emu/melonDS.git synced 2025-07-22 05:40:15 -06:00
Code Issues Packages Projects Releases Wiki Activity

GBACart: simulate open-bus decay roughly. fixes #1093

Browse Source
This commit is contained in:
Arisotura
2021-05-04 12:58:59 +02:00
parent b7d5a7db75
commit 50721719d2
3 changed files with 42 additions and 29 deletions
Download Patch File Download Diff File Expand all files Collapse all files

54
src/NDS.cpp
View File

@ -1242,33 +1242,35 @@ void SetWifiWaitCnt(u16 val)
void SetGBASlotTimings()
{
int curcpu = (ExMemCnt[0] >> 7) & 0x1;
const int ntimings[4] = {10, 8, 6, 18};
const u16 openbus[4] = {0xFE08, 0x0000, 0x0000, 0xFFFF};
u16 curcnt = ExMemCnt[curcpu];
int ramN = ntimings[curcnt & 0x3];
int romN = ntimings[(curcnt>>2) & 0x3];
int romS = (curcnt & 0x10) ? 4 : 6;
u16 curcnt;
int ramN, romN, romS;
// TODO: PHI pin thing?
curcnt = ExMemCnt[0];
ramN = ntimings[curcnt & 0x3];
romN = ntimings[(curcnt>>2) & 0x3];
romS = (curcnt & 0x10) ? 4 : 6;
if (curcpu == 0)
{
SetARM9RegionTimings(0x08000000, 0x0A000000, 16, romN + 3, romS);
SetARM9RegionTimings(0x0A000000, 0x0B000000, 8, ramN + 3, ramN);
SetARM9RegionTimings(0x08000000, 0x0A000000, 16, romN + 3, romS);
SetARM9RegionTimings(0x0A000000, 0x0B000000, 8, ramN + 3, ramN);
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);
curcnt = ExMemCnt[1];
ramN = ntimings[curcnt & 0x3];
romN = ntimings[(curcnt>>2) & 0x3];
romS = (curcnt & 0x10) ? 4 : 6;
SetARM7RegionTimings(0x08000000, 0x0A000000, 16, romN, romS);
SetARM7RegionTimings(0x0A000000, 0x0B000000, 8, ramN, ramN);
}
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]);
}
@ -1863,8 +1865,8 @@ void debug(u32 param)
//for (int i = 0; i < 9; i++)
// printf("VRAM %c: %02X\n", 'A'+i, GPU::VRAMCNT[i]);
/*FILE*
shit = fopen("debug/party.bin", "wb");
FILE*
shit = fopen("debug/construct.bin", "wb");
fwrite(ARM9->ITCM, 0x8000, 1, shit);
for (u32 i = 0x02000000; i < 0x02400000; i+=4)
{
@ -1876,9 +1878,9 @@ void debug(u32 param)
u32 val = ARM7Read32(i);
fwrite(&val, 4, 1, shit);
}
fclose(shit);*/
fclose(shit);
FILE*
/*FILE*
shit = fopen("debug/power9.bin", "wb");
for (u32 i = 0x02000000; i < 0x04000000; i+=4)
{
@ -1892,7 +1894,7 @@ void debug(u32 param)
u32 val = DSi::ARM7Read32(i);
fwrite(&val, 4, 1, shit);
}
fclose(shit);
fclose(shit);*/
}