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EGA now supports < 256kb video memory.

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This commit is contained in:
SarahW 2017-07-18 21:47:25 +01:00
commit 80a411b85f
2 changed files with 36 additions and 1 deletions
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36
src/vid_ega.c
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@ -636,6 +636,9 @@ void ega_write(uint32_t addr, uint8_t val, void *p)
addr <<= 2;
if (addr >= ega->vram_limit)
return;
if (!(ega->gdcreg[6] & 1))
fullchange = 2;
@ -766,7 +769,9 @@ uint8_t ega_read(uint32_t addr, void *p)
}
addr <<= 2;
if (addr >= ega->vram_limit)
return 0xff;
ega->la = ega->vram[addr];
ega->lb = ega->vram[addr | 0x1];
ega->lc = ega->vram[addr | 0x2];
@ -869,6 +874,8 @@ void ega_init(ega_t *ega, int monitor_type, int is_mono)
ega->pallook = pallook16;
egaswitches = monitor_type & 0xf;
ega->vram_limit = 256 * 1024;
ega->vrammask = ega->vram_limit-1;
}
void *ega_standalone_init()
@ -895,6 +902,9 @@ void *ega_standalone_init()
monitor_type = device_get_config_int("monitor_type");
ega_init(ega, monitor_type, (monitor_type & 0xf) == 10);
ega->vram_limit = device_get_config_int("memory") * 1024;
ega->vrammask = ega->vram_limit-1;
mem_mapping_add(&ega->mapping, 0xa0000, 0x20000, ega_read, NULL, NULL, ega_write, NULL, NULL, NULL, MEM_MAPPING_EXTERNAL, ega);
timer_add(ega_poll, &ega->vidtime, TIMER_ALWAYS_ENABLED, ega);
io_sethandler(0x03a0, 0x0040, ega_in, NULL, NULL, ega_out, NULL, NULL, ega);
@ -940,6 +950,30 @@ void ega_add_status_info(char *s, int max_len, void *p)
static device_config_t ega_config[] =
{
{
.name = "memory",
.description = "Memory size",
.type = CONFIG_SELECTION,
.selection =
{
{
.description = "64 kB",
.value = 64
},
{
.description = "128 kB",
.value = 128
},
{
.description = "256 kB",
.value = 256
},
{
.description = ""
}
},
.default_int = 256
},
{
.name = "monitor_type",
.description = "Monitor type",

1
src/vid_ega.h
View file

@ -60,6 +60,7 @@ typedef struct ega_t
uint8_t *vram;
int vrammask;
uint32_t vram_limit;
int video_res_x, video_res_y, video_bpp;
int frames;