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GBHawk: Fix start up time of HDMA

This commit is contained in:
alyosha-tas 2020-08-04 10:14:47 -04:00
parent 75aca0e7c6
commit c8b8efedac
2 changed files with 26 additions and 6 deletions
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14
src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/GBC_GB_PPU.cs
View File

@ -20,12 +20,13 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
public byte OBJ_transfer_byte;
// HDMA is unique to GBC, do it as part of the PPU tick
public bool HDMA_can_start;
public byte HDMA_src_hi;
public byte HDMA_src_lo;
public byte HDMA_dest_hi;
public byte HDMA_dest_lo;
public int HDMA_tick;
public byte HDMA_byte;
public int HDMA_tick;
// the first read on GBA (and first two on GBC) encounter access glitches if the source address is VRAM
public byte HDMA_VRAM_access_glitch;
@ -357,7 +358,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
{
// only transfer during mode 0, and only 16 bytes at a time
// cycle > 90 prevents triggering early when turning on LCD (presumably the real event is transition from mode 3 to 0.)
if (((STAT & 3) == 0) && (LY != last_HBL) && HBL_test && (LY_inc == 1) && (cycle > 90))
if (((STAT & 3) == 0) && (LY != last_HBL) && HBL_test && (LY_inc == 1) && (cycle > 90) && HDMA_can_start)
{
HBL_HDMA_go = true;
HBL_test = false;
@ -798,6 +799,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
evaled_sprites = 0;
window_pre_render = false;
window_latch = LCDC.Bit(5);
HDMA_can_start = false;
total_counter = 0;
@ -1310,7 +1312,14 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
read_case--;
break;
case 18:
case 19:
case 20:
read_case++;
break;
case 21:
// hardware tests indicate that HDMA starts at this point, not immediately after mode 3 ends
rendering_complete = true;
HDMA_can_start = true;
break;
}
internal_cycle++;
@ -1687,6 +1696,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
ser.Sync(nameof(HDMA_tick), ref HDMA_tick);
ser.Sync(nameof(HDMA_byte), ref HDMA_byte);
ser.Sync(nameof(HDMA_VRAM_access_glitch), ref HDMA_VRAM_access_glitch);
ser.Sync(nameof(HDMA_can_start), ref HDMA_can_start);
ser.Sync(nameof(VRAM_sel), ref VRAM_sel);
ser.Sync(nameof(BG_V_flip), ref BG_V_flip);

18
src/BizHawk.Emulation.Cores/Consoles/Nintendo/GBHawk/GBC_PPU.cs
View File

@ -18,12 +18,13 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
public byte OBJ_transfer_byte;
// HDMA is unique to GBC, do it as part of the PPU tick
public bool HDMA_can_start;
public byte HDMA_src_hi;
public byte HDMA_src_lo;
public byte HDMA_dest_hi;
public byte HDMA_dest_lo;
public int HDMA_tick;
public byte HDMA_byte;
public int HDMA_tick;
// the first read on GBA (and first two on GBC) encounter access glitches if the source address is VRAM
public byte HDMA_VRAM_access_glitch;
@ -349,7 +350,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
{
// only transfer during mode 0, and only 16 bytes at a time
// cycle > 90 prevents triggering early when turning on LCD (presumably the real event is transition from mode 3 to 0.)
if (((STAT & 3) == 0) && (LY != last_HBL) && HBL_test && (LY_inc == 1) && (cycle > 90))
if (((STAT & 3) == 0) && (LY != last_HBL) && HBL_test && (LY_inc == 1) && (cycle > 90) && HDMA_can_start)
{
HBL_HDMA_go = true;
HBL_test = false;
@ -789,6 +790,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
evaled_sprites = 0;
window_pre_render = false;
window_latch = LCDC.Bit(5);
HDMA_can_start = false;
total_counter = 0;
@ -1235,15 +1237,15 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
OAM_access_write = true;
VRAM_access_read = true;
VRAM_access_write = true;
read_case = 18;
}
else
{
STAT &= 0xFC;
STAT |= 0x00;
if (STAT.Bit(3)) { HBL_INT = true; }
// the CPU has to be able to see the transition from mode 3 to mode 0 to start HDMA
}
}
break;
@ -1266,7 +1268,14 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
read_case--;
break;
case 18:
case 19:
case 20:
read_case++;
break;
case 21:
// hardware tests indicate that HDMA starts at this point, not immediately after mode 3 ends
rendering_complete = true;
HDMA_can_start = true;
break;
}
internal_cycle++;
@ -1618,6 +1627,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.GBHawk
ser.Sync(nameof(HDMA_tick), ref HDMA_tick);
ser.Sync(nameof(HDMA_byte), ref HDMA_byte);
ser.Sync(nameof(HDMA_VRAM_access_glitch), ref HDMA_VRAM_access_glitch);
ser.Sync(nameof(HDMA_can_start), ref HDMA_can_start);
ser.Sync(nameof(VRAM_sel), ref VRAM_sel);
ser.Sync(nameof(BG_V_flip), ref BG_V_flip);