forked from nocrew/ostis
/
rom.c
139 lines (116 loc) · 2.81 KB
/
rom.c
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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "common.h"
#include "prefs.h"
#include "mmu.h"
#include "state.h"
#include "diag.h"
static LONG ROMSIZE;
static LONG ROMBASE;
#define ROMSIZE_NEW 262144
#define ROMBASE_NEW 0xe00000
#define ROMSIZE_OLD 196608
#define ROMBASE_OLD 0xfc0000
#define ROMSIZE2 8
#define ROMBASE2 0
static BYTE *memory;
static BYTE *memory2;
HANDLE_DIAGNOSTICS(rom)
static BYTE *real(LONG addr)
{
if(addr < ROMBASE)
return memory2+addr-ROMBASE2;
else
return memory+addr-ROMBASE;
}
static BYTE rom_read_byte(LONG addr)
{
return *(real(addr));
}
static WORD rom_read_word(LONG addr)
{
return (rom_read_byte(addr)<<8)|rom_read_byte(addr+1);
}
static int rom_state_collect(struct mmu_state *state)
{
if(!strcmp("ROM0", state->id)) {
state->size = ROMSIZE;
state->data = xmalloc(state->size);
if(state->data == NULL)
return STATE_INVALID;
memcpy(state->data, memory, state->size);
} else {
state->size = ROMSIZE2;
state->data = xmalloc(state->size);
if(state->data == NULL)
return STATE_INVALID;
memcpy(state->data, memory2, state->size);
}
return STATE_VALID;
}
static void rom_state_restore(struct mmu_state *state)
{
long size;
size = state->size;
if(!strcmp("ROM0", state->id)) {
if(state->size > ROMSIZE) size = ROMSIZE;
memcpy(memory, state->data, size);
} else {
if(state->size > ROMSIZE2) size = ROMSIZE2;
memcpy(memory2, state->data, size);
}
}
void rom_init()
{
struct mmu *rom,*rom2;
FILE *f;
f = fopen(prefs.tosimage, "rb");
if(!f) {
FATAL("Could not open TOS image file\n");
}
fseek(f, 0, SEEK_END);
ROMSIZE = ftell(f);
rewind(f);
switch(ROMSIZE) {
case ROMSIZE_OLD:
ROMBASE = ROMBASE_OLD;
break;
case ROMSIZE_NEW:
ROMBASE = ROMBASE_NEW;
break;
default:
FATAL("Unknown ROM image format");
}
memory = xmalloc(sizeof(BYTE) * ROMSIZE);
if(!memory) {
return;
}
rom = mmu_create("ROM0", "ROM");
rom->start = ROMBASE;
rom->size = ROMSIZE;
rom->read_byte = rom_read_byte;
rom->read_word = rom_read_word;
rom->state_collect = rom_state_collect;
rom->state_restore = rom_state_restore;
rom->diagnostics = rom_diagnostics;
mmu_register(rom);
if(fread(memory, 1, ROMSIZE, f) != ROMSIZE) {
FATAL("Error reading TOS image file");
}
fclose(f);
memory2 = xmalloc(sizeof(BYTE) * ROMSIZE2);
if(!memory2) {
return;
}
rom2 = mmu_create("ROM1", "First 8 bytes of memory");
memcpy(memory2, memory, ROMSIZE2);
rom2->start = ROMBASE2; /* First 8 bytes of memory is ROM */
rom2->size = ROMSIZE2;
rom2->read_byte = rom_read_byte;
rom2->read_word = rom_read_word;
rom2->state_collect = rom_state_collect;
rom2->state_restore = rom_state_restore;
rom2->diagnostics = rom_diagnostics;
mmu_register(rom2);
}