fix for X-Men 2 and Moonwalker on Megadrive (new DMA code ported from latest picodrive+tweaks)
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dinkc64
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c28eb1d1c2
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@ -34,7 +34,7 @@
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#define MAX_CARTRIDGE_SIZE 0xc00000
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#define MAX_SRAM_SIZE 0x010000
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static INT32 cycles_68k, cycles_z80;
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static INT32 cycles_68k, cycles_z80, dma_xfers=0, video_status=0;
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typedef void (*MegadriveCb)();
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static MegadriveCb MegadriveCallback;
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@ -43,10 +43,12 @@ struct PicoVideo {
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UINT8 reg[0x20];
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UINT32 command; // 32-bit Command
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UINT8 pending; // 1 if waiting for second half of 32-bit command
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UINT8 type; // Command type (v/c/vsram read/write)
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UINT8 type; // Command type (v/c/vsram read/write)
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UINT16 addr; // Read/Write address
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INT32 status; // Status bits
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INT32 status; // Status bits
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UINT8 pending_ints; // pending interrupts: ??VH????
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INT8 lwrite_cnt; // VDP write count during active display line
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UINT16 v_counter; // V-counter
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UINT8 pad[0x13]; //
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};
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@ -525,6 +527,59 @@ static INT32 GetDmaLength()
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return len;
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}
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// dma2vram settings are just hacks to unglitch Legend of Galahad (needs <= 104 to work)
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// same for Outrunners (92-121, when active is set to 24)
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// 96 is VR hack
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static const int dma_timings[] = {
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167, 167, 166, 83, // vblank: 32cell: dma2vram dma2[vs|c]ram vram_fill vram_copy
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102, 205, 204, 102, // vblank: 40cell:
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16, 16, 15, 8, // active: 32cell:
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24, 18, 17, 9 // ...
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};
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static const int dma_bsycles[] = {
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(488<<8)/167, (488<<8)/167, (488<<8)/166, (488<<8)/83,
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(488<<8)/102, (488<<8)/233, (488<<8)/204, (488<<8)/102,
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(488<<8)/16, (488<<8)/16, (488<<8)/15, (488<<8)/8,
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(488<<8)/24, (488<<8)/18, (488<<8)/17, (488<<8)/9
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};
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static UINT32 CheckDMA(void)
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{
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int burn = 0, xfers_can, dma_op = RamVReg->reg[0x17]>>6; // see gens for 00 and 01 modes
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int xfers = dma_xfers;
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int dma_op1;
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if(!(dma_op&2)) dma_op = (/*Pico.video.type==1*/0) ? 0 : 1; // setting dma_timings offset here according to Gens
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dma_op1 = dma_op;
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if(RamVReg->reg[12] & 1) dma_op |= 4; // 40 cell mode?
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if(!(video_status&8)&&(RamVReg->reg[1]&0x40)) dma_op|=8; // active display?
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xfers_can = dma_timings[dma_op];
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if(xfers <= xfers_can)
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{
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if(dma_op&2) video_status&=~2; // dma no longer busy
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else {
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burn = xfers * dma_bsycles[dma_op] >> 8; // have to be approximate because can't afford division..
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}
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dma_xfers = 0;
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} else {
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if(!(dma_op&2)) burn = 488;
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dma_xfers -= xfers_can;
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}
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//elprintf(EL_VDPDMA, "~Dma %i op=%i can=%i burn=%i [%i]", Pico.m.dma_xfers, dma_op1, xfers_can, burn, SekCyclesDone());
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//dprintf("~aim: %i, cnt: %i", SekCycleAim, SekCycleCnt);
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//bprintf(0, _T("burn[%d]"), burn);
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return burn;
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}
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static inline int DMABURN() { // add cycles to the 68k cpu
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if (dma_xfers) {
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return CheckDMA();
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//SekRunAdjust( 0 - cycles_to_add );
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} else return 0;
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}
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static void DmaSlow(INT32 len)
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{
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UINT16 *pd=0, *pdend, *r;
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@ -554,10 +609,12 @@ static void DmaSlow(INT32 len)
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} else burn = DmaSlowBurn(len);
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//SekCyclesBurn(burn);
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SekRunAdjust( 0 - burn );
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if(!(RamVReg->status & 8))
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SekRunEnd();
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video_status |= 2; // dma busy
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dma_xfers += len;
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DMABURN();
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//SekRunAdjust( 0 - burn );
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//if(!(RamVReg->status & 8))
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// SekRunEnd();
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//dprintf("DmaSlow burn: %i @ %06x", burn, SekPc);
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switch ( RamVReg->type ) {
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@ -619,6 +676,9 @@ static void DmaCopy(INT32 len)
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//dprintf("DmaCopy len %i [%i|%i]", len, Pico.m.scanline, SekCyclesDone());
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video_status |= 2; // dma busy
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dma_xfers += len;
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source = RamVReg->reg[0x15];
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source |= RamVReg->reg[0x16]<<8;
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vrs = vr + source;
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@ -647,6 +707,8 @@ static void DmaFill(INT32 data)
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// from Charles MacDonald's genvdp.txt:
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// Write lower byte to address specified
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video_status |= 2; // dma busy
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dma_xfers += len;
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vr[a] = (UINT8) data;
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a = (UINT16)(a+inc);
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@ -4129,7 +4191,7 @@ INT32 MegadriveFrame()
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cycles_68k = total_68k_cycles / lines;
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cycles_z80 = total_z80_cycles / lines;
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RamVReg->status &= ~0x88; // clear V-Int, come out of vblank
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for (INT32 y=0; y<lines; y++) {
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@ -4158,8 +4220,7 @@ INT32 MegadriveFrame()
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RamVReg->status |= 0x88; // V-Int happened, go into vblank
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// there must be a gap between H and V ints, also after vblank bit set (Mazin Saga, Bram Stoker's Dracula)
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// done_68k+=SekRun(128);
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BurnTimerUpdate(((y + 1) * cycles_68k) + 128);
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BurnTimerUpdate(((y + 1) * cycles_68k) + /*CYCLES_M68K_VINT_LAG*/ 128 + DMABURN() - cycles_68k);
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RamVReg->pending_ints |= 0x20;
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if(RamVReg->reg[1] & 0x20) {
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@ -4172,8 +4233,8 @@ INT32 MegadriveFrame()
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PicoLine(y);
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// Run scanline
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BurnTimerUpdate((y + 1) * cycles_68k);
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BurnTimerUpdate((y + 1) * cycles_68k + DMABURN());
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if (Z80HasBus && !MegadriveZ80Reset) {
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done_z80 += ZetRun(((y + 1) * cycles_z80) - done_z80);
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if (y == line_sample) ZetSetIRQLine(0, ZET_IRQSTATUS_ACK);
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@ -4190,7 +4251,7 @@ INT32 MegadriveFrame()
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ZetRun(total_z80_cycles - done_z80);
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}
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}
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if (pBurnSoundOut) {
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BurnYM2612Update(pBurnSoundOut, nBurnSoundLen);
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SN76496Update(0, pBurnSoundOut, nBurnSoundLen);
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