diff options
| author | Michael Pavone <pavone@retrodev.com> | 2017-03-18 17:09:14 -0700 |
|---|---|---|
| committer | Michael Pavone <pavone@retrodev.com> | 2017-03-18 17:09:14 -0700 |
| commit | 401596ec874495e53dc65290f08393fc9aed804d (patch) | |
| tree | 4f375ebdf43b7b469abe9ffecf088678e76e16ac /vdp.c | |
| parent | c56f74f0913bc7c2ab200dee194b1d3df5d93522 (diff) | |
Remove hacky post-DMA delay add proper pre-DMA delay based on logic analyzer capture. 512 color screen is a bit messed up but mostly works. Needs investigation
Diffstat (limited to 'vdp.c')
| -rw-r--r-- | vdp.c | 5 |
1 files changed, 4 insertions, 1 deletions
@@ -2482,13 +2482,16 @@ int vdp_control_port_write(vdp_context * context, uint16_t value) // if((context->regs[REG_DMASRC_H] & 0xC0) != 0x80) { //DMA copy or 68K -> VDP, transfer starts immediately - context->flags |= FLAG_DMA_RUN; context->dma_cd = context->cd; //printf("DMA start (length: %X) at cycle %d, frame: %d, vcounter: %d, hslot: %d\n", (context->regs[REG_DMALEN_H] << 8) | context->regs[REG_DMALEN_L], context->cycles, context->frame, context->vcounter, context->hslot); if (!(context->regs[REG_DMASRC_H] & 0x80)) { //printf("DMA Address: %X, New CD: %X, Source: %X, Length: %X\n", context->address, context->cd, (context->regs[REG_DMASRC_H] << 17) | (context->regs[REG_DMASRC_M] << 9) | (context->regs[REG_DMASRC_L] << 1), context->regs[REG_DMALEN_H] << 8 | context->regs[REG_DMALEN_L]); + //68K -> VDP DMA takes 4 slots to actually start reading even though it acquires the bus immediately + vdp_run_context(context, context->cycles + 16 * ((context->regs[REG_MODE_2] & BIT_MODE_5) && (context->regs[REG_MODE_4] & BIT_H40) ? 4 : 5)); + context->flags |= FLAG_DMA_RUN; return 1; } else { + context->flags |= FLAG_DMA_RUN; //printf("DMA Copy Address: %X, New CD: %X, Source: %X\n", context->address, context->cd, (context->regs[REG_DMASRC_M] << 8) | context->regs[REG_DMASRC_L]); } } else { |