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Rework video memory handling to cater for open bus and VRAM address wrapping. Fixes more hangs with Trio64 and Windows 95.

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This commit is contained in:
SarahW 2017-10-22 12:41:10 +01:00
commit 39a68d757b
10 changed files with 174 additions and 117 deletions
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15
src/vid_svga.h
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@ -15,7 +15,18 @@ typedef struct svga_t
uint8_t miscout;
int vidclock;
uint32_t vram_limit;
/*The three variables below allow us to implement memory maps like that seen on a 1MB Trio64 :
0MB-1MB - VRAM
1MB-2MB - VRAM mirror
2MB-4MB - open bus
4MB-xMB - mirror of above
For the example memory map, decode_mask would be 4MB-1 (4MB address space), vram_max would be 2MB
(present video memory only responds to first 2MB), vram_mask would be 1MB-1 (video memory wraps at 1MB)
*/
uint32_t decode_mask;
uint32_t vram_max;
uint32_t vram_mask;
uint8_t la, lb, lc, ld;
@ -71,7 +82,7 @@ typedef struct svga_t
uint8_t *vram;
uint8_t *changedvram;
int vrammask;
uint32_t vram_display_mask;
uint32_t banked_mask;
uint32_t write_bank, read_bank;