Mercurial > repos > blastem

changeset 2129:4c9e447aa25b

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Pause word RAM DMA while word RAM is switched to main CPU
author Michael Pavone <pavone@retrodev.com>
date Sun, 13 Mar 2022 11:49:07 -0700
parents b0dcf5c9f353
children 28b6453cf7e3
files segacd.c
diffstat 1 files changed, 8 insertions(+), 1 deletions(-) [+]
line wrap: on
line diff
--- a/segacd.c	Sun Mar 13 11:36:06 2022 -0700
+++ b/segacd.c	Sun Mar 13 11:49:07 2022 -0700
@@ -920,7 +920,9 @@
 			m68k_invalidate_code_range(cd->m68k, 0x0C0000 + dma_addr - 1, 0x0C0000 + dma_addr + 1);
 		} else {
 			//2M mode, check if Sub CPU has access
-			if (!(cd->gate_array[GA_MEM_MODE] & BIT_RET)) {
+			if (cd->main_has_word2m) {
+				return 0;
+			} else {
 				cd_graphics_run(cd, cd->cdc.cycle);
 				dma_addr &= (1 << 18) - 1;
 				cd->word_ram[dma_addr >> 1] = cd->gate_array[GA_CDC_HOST_DATA];
@@ -1196,6 +1198,11 @@
 				cd->gate_array[reg] &= ~BIT_RET;
 				cd->main_has_word2m = 0;
 
+				uint16_t dst = cd->gate_array[GA_CDC_CTRL] >> 8 & 0x7;
+				if (dst == DST_WORD_RAM) {
+					lc8951_resume_transfer(&cd->cdc, cd->cdc.cycle);
+				}
+
 				m68k_invalidate_code_range(m68k, cd->base + 0x200000, cd->base + 0x240000);
 				m68k_invalidate_code_range(cd->m68k, 0x080000, 0x0C0000);
 			}