diff options
Diffstat (limited to 'src/GPU.cpp')
| -rw-r--r-- | src/GPU.cpp | 48 |
1 files changed, 37 insertions, 11 deletions
diff --git a/src/GPU.cpp b/src/GPU.cpp index 20cfadd..ac3684d 100644 --- a/src/GPU.cpp +++ b/src/GPU.cpp @@ -33,6 +33,8 @@ u16 VCount; u32 NextVCount; u16 TotalScanlines; +bool RunFIFO; + u16 DispStat[2], VMatch[2]; u8 Palette[2*1024]; @@ -606,8 +608,36 @@ void DisplaySwap(u32 val) } +void DisplayFIFO(u32 x) +{ + // sample the FIFO + // as this starts 16 cycles (~3 pixels) before display start, + // we aren't aligned to the 8-pixel grid + if (x > 0) + { + if (x == 8) + GPU2D_A->SampleFIFO(0, 5); + else + GPU2D_A->SampleFIFO(x-11, 8); + } + + if (x < 256) + { + // transfer the next 8 pixels + NDS::CheckDMAs(0, 0x04); + NDS::ScheduleEvent(NDS::Event_DisplayFIFO, true, 6*8, DisplayFIFO, x+8); + } + else + GPU2D_A->SampleFIFO(253, 3); // sample the remaining pixels +} + void StartFrame() { + // only run the display FIFO if needed: + // * if it is used for display or capture + // * if we have display FIFO DMA + RunFIFO = GPU2D_A->UsesFIFO() || NDS::DMAsInMode(0, 0x04); + TotalScanlines = 0; StartScanline(0); } @@ -619,6 +649,11 @@ void StartHBlank(u32 line) if (VCount < 192) { + // draw + // note: this should start 48 cycles after the scanline start + GPU2D_A->DrawScanline(line); + GPU2D_B->DrawScanline(line); + NDS::CheckDMAs(0, 0x02); } else if (VCount == 215) @@ -682,23 +717,14 @@ void StartScanline(u32 line) if (line < 192) { - // fill a line from the display FIFO if needed. - // this isn't how the real thing works, but emulating it - // properly would be too much trouble given barely anything - // uses FIFO display - // (TODO, eventually: emulate it properly) - if (VCount < 192) - NDS::CheckDMAs(0, 0x04); - if (line == 0) { GPU2D_A->VBlankEnd(); GPU2D_B->VBlankEnd(); } - // draw - GPU2D_A->DrawScanline(line); - GPU2D_B->DrawScanline(line); + if (RunFIFO) + NDS::ScheduleEvent(NDS::Event_DisplayFIFO, true, 32, DisplayFIFO, 0); } if (VCount == 262) |