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Several 286/386SX models can now have less than 1MB of RAM.

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Memory remapping code restructured.
Patch from Greatpsycho.
This commit is contained in:
SarahW 2017-06-18 20:15:46 +01:00
commit 7234e2c3be
6 changed files with 100 additions and 64 deletions
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114
src/mem.c
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@ -1561,6 +1561,50 @@ void mem_write_raml(uint32_t addr, uint32_t val, void *priv)
mem_write_raml_page(addr, val, &pages[addr >> 12]);
}
static uint32_t remap_start_addr;
uint8_t mem_read_remapped(uint32_t addr, void *priv)
{
addr = 0xA0000 + (addr - remap_start_addr);
addreadlookup(mem_logical_addr, addr);
return ram[addr];
}
uint16_t mem_read_remappedw(uint32_t addr, void *priv)
{
addr = 0xA0000 + (addr - remap_start_addr);
addreadlookup(mem_logical_addr, addr);
return *(uint16_t *)&ram[addr];
}
uint32_t mem_read_remappedl(uint32_t addr, void *priv)
{
addr = 0xA0000 + (addr - remap_start_addr);
addreadlookup(mem_logical_addr, addr);
return *(uint32_t *)&ram[addr];
}
void mem_write_remapped(uint32_t addr, uint8_t val, void *priv)
{
uint32_t oldaddr = addr;
addr = 0xA0000 + (addr - remap_start_addr);
addwritelookup(mem_logical_addr, addr);
mem_write_ramb_page(addr, val, &pages[oldaddr >> 12]);
}
void mem_write_remappedw(uint32_t addr, uint16_t val, void *priv)
{
uint32_t oldaddr = addr;
addr = 0xA0000 + (addr - remap_start_addr);
addwritelookup(mem_logical_addr, addr);
mem_write_ramw_page(addr, val, &pages[oldaddr >> 12]);
}
void mem_write_remappedl(uint32_t addr, uint32_t val, void *priv)
{
uint32_t oldaddr = addr;
addr = 0xA0000 + (addr - remap_start_addr);
addwritelookup(mem_logical_addr, addr);
mem_write_raml_page(addr, val, &pages[oldaddr >> 12]);
}
uint8_t mem_read_bios(uint32_t addr, void *priv)
{
if (AMIBIOS && (addr&0xFFFFF)==0xF8281) /*This is read constantly during AMIBIOS POST, but is never written to. It's clearly a status register of some kind, but for what?*/
@ -1858,7 +1902,7 @@ void mem_init()
{
int c;
ram = malloc((mem_size + 384) * 1024);
ram = malloc(mem_size * 1024);
// rom = malloc(0x20000);
readlookup2 = malloc(1024 * 1024 * sizeof(uintptr_t));
writelookup2 = malloc(1024 * 1024 * sizeof(uintptr_t));
@ -1866,12 +1910,12 @@ void mem_init()
pages = malloc((((mem_size + 384) * 1024) >> 12) * sizeof(page_t));
page_lookup = malloc((1 << 20) * sizeof(page_t *));
memset(ram, 0, (mem_size + 384) * 1024);
memset(ram, 0, mem_size * 1024);
memset(pages, 0, (((mem_size + 384) * 1024) >> 12) * sizeof(page_t));
memset(page_lookup, 0, (1 << 20) * sizeof(page_t *));
for (c = 0; c < ((mem_size * 1024) >> 12); c++)
for (c = 0; c < (((mem_size + 384) * 1024) >> 12); c++)
{
pages[c].mem = &ram[c << 12];
pages[c].write_b = mem_write_ramb_page;
@ -1880,7 +1924,7 @@ void mem_init()
}
memset(isram, 0, sizeof(isram));
for (c = 0; c < (mem_size / 256); c++)
for (c = 0; c < (mem_size / 64); c++)
{
isram[c] = 1;
if (c >= 0xa && c <= 0xf)
@ -1916,49 +1960,39 @@ void mem_init()
// pclog("Mem resize %i %i\n",mem_size,c);
}
void mem_remap_top_256k()
static void mem_remap_top(int max_size)
{
int c;
for (c = ((mem_size * 1024) >> 12); c < (((mem_size + 256) * 1024) >> 12); c++)
if (mem_size > 640)
{
pages[c].mem = &ram[c << 12];
pages[c].write_b = mem_write_ramb_page;
pages[c].write_w = mem_write_ramw_page;
pages[c].write_l = mem_write_raml_page;
}
uint32_t start = (mem_size >= 1024) ? mem_size : 1024;
int size = mem_size - 640;
if (size > max_size)
size = max_size;
remap_start_addr = start * 1024;
for (c = ((start * 1024) >> 12); c < (((start + size) * 1024) >> 12); c++)
{
pages[c].mem = &ram[0xA0000 + ((c - ((start * 1024) >> 12)) << 12)];
pages[c].write_b = mem_write_ramb_page;
pages[c].write_w = mem_write_ramw_page;
pages[c].write_l = mem_write_raml_page;
}
for (c = (mem_size / 256); c < ((mem_size + 256) / 256); c++)
{
isram[c] = 1;
if (c >= 0xa && c <= 0xd)
isram[c] = 0;
mem_set_mem_state(start * 1024, size * 1024, MEM_READ_INTERNAL | MEM_WRITE_INTERNAL);
mem_mapping_add(&ram_remapped_mapping, start * 1024, size * 1024, mem_read_remapped, mem_read_remappedw, mem_read_remappedl, mem_write_remapped, mem_write_remappedw, mem_write_remappedl, ram + 0xA0000, MEM_MAPPING_INTERNAL, NULL);
}
}
mem_set_mem_state(mem_size * 1024, 256 * 1024, MEM_READ_INTERNAL | MEM_WRITE_INTERNAL);
mem_mapping_add(&ram_remapped_mapping, mem_size * 1024, 256 * 1024, mem_read_ram, mem_read_ramw, mem_read_raml, mem_write_ram, mem_write_ramw, mem_write_raml, ram + (mem_size * 1024), MEM_MAPPING_INTERNAL, NULL);
void mem_remap_top_256k()
{
mem_remap_top(256);
}
void mem_remap_top_384k()
{
int c;
for (c = ((mem_size * 1024) >> 12); c < (((mem_size + 384) * 1024) >> 12); c++)
{
pages[c].mem = &ram[c << 12];
pages[c].write_b = mem_write_ramb_page;
pages[c].write_w = mem_write_ramw_page;
pages[c].write_l = mem_write_raml_page;
}
for (c = (mem_size / 256); c < ((mem_size + 384) / 256); c++)
{
isram[c] = 1;
if (c >= 0xa && c <= 0xf)
isram[c] = 0;
}
mem_set_mem_state(mem_size * 1024, 384 * 1024, MEM_READ_INTERNAL | MEM_WRITE_INTERNAL);
mem_mapping_add(&ram_remapped_mapping, mem_size * 1024, 384 * 1024, mem_read_ram, mem_read_ramw, mem_read_raml, mem_write_ram, mem_write_ramw, mem_write_raml, ram + (mem_size * 1024), MEM_MAPPING_INTERNAL, NULL);
mem_remap_top(384);
}
void mem_resize()
@ -1966,8 +2000,8 @@ void mem_resize()
int c;
free(ram);
ram = malloc((mem_size + 384) * 1024);
memset(ram, 0, (mem_size + 384) * 1024);
ram = malloc(mem_size * 1024);
memset(ram, 0, mem_size * 1024);
free(pages);
pages = malloc((((mem_size + 384) * 1024) >> 12) * sizeof(page_t));
@ -1981,7 +2015,7 @@ void mem_resize()
}
memset(isram, 0, sizeof(isram));
for (c = 0; c < (mem_size / 256); c++)
for (c = 0; c < (mem_size / 64); c++)
{
isram[c] = 1;
if (c >= 0xa && c <= 0xf)