Mercurial > repos > blastem
changeset 1321:0849e9356bfe
Fix time 68K is locked out of bus when doing a 128KB VRAM mode DMA transfer. Fixes a number of problems in Overdrive 2
author | Michael Pavone <pavone@retrodev.com> |
---|---|
date | Mon, 17 Apr 2017 23:58:21 -0700 |
parents | df3d690cb2c3 |
children | b1423d432c0e |
files | vdp.c |
diffstat | 1 files changed, 4 insertions(+), 1 deletions(-) [+] |
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--- a/vdp.c Mon Apr 17 20:54:33 2017 -0700 +++ b/vdp.c Mon Apr 17 23:58:21 2017 -0700 @@ -2432,9 +2432,12 @@ dmalen = 0x10000; } uint32_t min_dma_complete = dmalen * (context->regs[REG_MODE_4] & BIT_H40 ? 16 : 20); - if ((context->regs[REG_DMASRC_H] & 0xC0) == 0xC0 || (context->cd & 0xF) == VRAM_WRITE) { + if ( + (context->regs[REG_DMASRC_H] & 0xC0) == 0xC0 + || (((context->cd & 0xF) == VRAM_WRITE) && !(context->regs[REG_MODE_2] & BIT_128K_VRAM))) { //DMA copies take twice as long to complete since they require a read and a write //DMA Fills and transfers to VRAM also take twice as long as it requires 2 writes for a single word + //unless 128KB mode is enabled min_dma_complete *= 2; } min_dma_complete += context->cycles;