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-rw-r--r--romdb.c226
1 files changed, 223 insertions, 3 deletions
diff --git a/romdb.c b/romdb.c
index fbfcef9..fce0c84 100644
--- a/romdb.c
+++ b/romdb.c
@@ -3,13 +3,140 @@
#include "config.h"
#include "romdb.h"
#include "util.h"
+#include "blastem.h"
#define TITLE_START 0x150
#define TITLE_END (TITLE_START+48)
#define GAME_ID_OFF 0x183
#define GAME_ID_LEN 8
+#define ROM_END 0x1A4
+#define RAM_ID 0x1B0
+#define RAM_FLAGS 0x1B2
+#define RAM_START 0x1B4
+#define RAM_END 0x1B8
#define REGION_START 0x1F0
+uint16_t read_sram_w(uint32_t address, m68k_context * context)
+{
+ genesis_context * gen = context->system;
+ address &= gen->save_ram_mask;
+ switch(gen->save_flags)
+ {
+ case RAM_FLAG_BOTH:
+ return gen->save_ram[address] << 8 | gen->save_ram[address+1];
+ case RAM_FLAG_EVEN:
+ return gen->save_ram[address >> 1] << 8 | 0xFF;
+ case RAM_FLAG_ODD:
+ return gen->save_ram[address >> 1] | 0xFF00;
+ }
+ return 0xFFFF;//We should never get here
+}
+
+uint8_t read_sram_b(uint32_t address, m68k_context * context)
+{
+ genesis_context * gen = context->system;
+ address &= gen->save_ram_mask;
+ switch(gen->save_flags)
+ {
+ case RAM_FLAG_BOTH:
+ return gen->save_ram[address];
+ case RAM_FLAG_EVEN:
+ if (address & 1) {
+ return 0xFF;
+ } else {
+ return gen->save_ram[address >> 1];
+ }
+ case RAM_FLAG_ODD:
+ if (address & 1) {
+ return gen->save_ram[address >> 1];
+ } else {
+ return 0xFF;
+ }
+ }
+ return 0xFF;//We should never get here
+}
+
+m68k_context * write_sram_area_w(uint32_t address, m68k_context * context, uint16_t value)
+{
+ genesis_context * gen = context->system;
+ if ((gen->bank_regs[0] & 0x3) == 1) {
+ address &= gen->save_ram_mask;
+ switch(gen->save_flags)
+ {
+ case RAM_FLAG_BOTH:
+ gen->save_ram[address] = value >> 8;
+ gen->save_ram[address+1] = value;
+ break;
+ case RAM_FLAG_EVEN:
+ gen->save_ram[address >> 1] = value >> 8;
+ break;
+ case RAM_FLAG_ODD:
+ gen->save_ram[address >> 1] = value;
+ break;
+ }
+ }
+ return context;
+}
+
+m68k_context * write_sram_area_b(uint32_t address, m68k_context * context, uint8_t value)
+{
+ genesis_context * gen = context->system;
+ if ((gen->bank_regs[0] & 0x3) == 1) {
+ address &= gen->save_ram_mask;
+ switch(gen->save_flags)
+ {
+ case RAM_FLAG_BOTH:
+ gen->save_ram[address] = value;
+ break;
+ case RAM_FLAG_EVEN:
+ if (!(address & 1)) {
+ gen->save_ram[address >> 1] = value;
+ }
+ break;
+ case RAM_FLAG_ODD:
+ if (address & 1) {
+ gen->save_ram[address >> 1] = value;
+ }
+ break;
+ }
+ }
+ return context;
+}
+
+m68k_context * write_bank_reg_w(uint32_t address, m68k_context * context, uint16_t value)
+{
+ genesis_context * gen = context->system;
+ address &= 0xE;
+ address >>= 1;
+ gen->bank_regs[address] = value;
+ if (!address) {
+ if (value & 1) {
+ context->mem_pointers[2] = NULL;
+ } else {
+ context->mem_pointers[2] = cart + 0x200000/2;
+ }
+ }
+ return context;
+}
+
+m68k_context * write_bank_reg_b(uint32_t address, m68k_context * context, uint8_t value)
+{
+ if (address & 1) {
+ genesis_context * gen = context->system;
+ address &= 0xE;
+ address >>= 1;
+ gen->bank_regs[address] = value;
+ if (!address) {
+ if (value & 1) {
+ context->mem_pointers[2] = NULL;
+ } else {
+ context->mem_pointers[2] = cart + 0x200000/2;
+ }
+ }
+ }
+ return context;
+}
+
tern_node *load_rom_db()
{
char *exe_dir = get_exe_dir();
@@ -77,16 +204,96 @@ uint8_t get_header_regions(uint8_t *rom)
return regions;
}
+uint32_t get_u32be(uint8_t *data)
+{
+ return *data << 24 | data[1] << 16 | data[2] << 8 | data[3];
+}
+
+void add_memmap_header(rom_info *info, uint8_t *rom, uint32_t size, memmap_chunk const *base_map, int base_chunks)
+{
+ if (rom[RAM_ID] == 'R' && rom[RAM_ID+1] == 'A') {
+ uint32_t rom_end = get_u32be(rom + ROM_END) + 1;
+ uint32_t ram_start = get_u32be(rom + RAM_START);
+ uint32_t ram_end = get_u32be(rom + RAM_END);
+ uint32_t ram_flags = info->save_type = rom[RAM_FLAGS] & RAM_FLAG_MASK;
+ ram_start &= 0xFFFFFE;
+ ram_end |= 1;
+
+ info->map_chunks = base_chunks + (ram_start >= rom_end ? 2 : 3);
+ info->map = malloc(sizeof(memmap_chunk) * info->map_chunks);
+ memset(info->map, 0, sizeof(memmap_chunk)*2);
+ memcpy(info->map+2, base_map, sizeof(memmap_chunk) * base_chunks);
+
+ if (ram_start >= rom_end) {
+ info->map[0].end = rom_end;
+ //TODO: ROM mirroring
+ info->map[0].mask = 0xFFFFFF;
+ info->map[0].flags = MMAP_READ;
+ info->map[0].buffer = rom;
+
+ info->map[1].start = ram_start;
+ info->map[1].mask = ram_end - ram_start;
+ info->map[1].end = ram_end + 1;
+ info->map[1].flags = MMAP_READ | MMAP_WRITE;
+ uint32_t size = info->map[1].mask + 1;
+ if (ram_flags == RAM_FLAG_ODD) {
+ info->map[1].flags |= MMAP_ONLY_ODD;
+ size /= 2;
+ } else if (ram_flags == RAM_FLAG_EVEN) {
+ info->map[1].flags |= MMAP_ONLY_EVEN;
+ size /= 2;
+ }
+ info->map[1].buffer = malloc(size);
+ } else {
+ //Assume the standard Sega mapper
+ info->map[0].end = 0x200000;
+ info->map[0].mask = 0xFFFFFF;
+ info->map[0].flags = MMAP_READ;
+ info->map[0].buffer = rom;
+
+ info->map[1].start = 0x200000;
+ info->map[1].end = 0x400000;
+ info->map[1].mask = 0x1FFFFF;
+ info->map[1].flags = MMAP_READ | MMAP_PTR_IDX | MMAP_FUNC_NULL;
+ info->map[1].ptr_index = 2;
+ info->map[1].read_16 = (read_16_fun)read_sram_w;//these will only be called when mem_pointers[2] == NULL
+ info->map[1].read_8 = (read_8_fun)read_sram_b;
+ info->map[1].write_16 = (write_16_fun)write_sram_area_w;//these will be called all writes to the area
+ info->map[1].write_8 = (write_8_fun)write_sram_area_b;
+ info->map[1].buffer = cart + 0x200000;
+
+ memmap_chunk *last = info->map + info->map_chunks - 1;
+ memset(last, 0, sizeof(memmap_chunk));
+ last->start = 0xA13000;
+ last->end = 0xA13100;
+ last->mask = 0xFF;
+ last->write_16 = (write_16_fun)write_bank_reg_w;
+ last->write_8 = (write_8_fun)write_bank_reg_b;
+ }
+ } else {
+ info->map_chunks = base_chunks + 1;
+ info->map = malloc(sizeof(memmap_chunk) * info->map_chunks);
+ memset(info->map, 0, sizeof(memmap_chunk));
+ memcpy(info->map+1, base_map, sizeof(memmap_chunk) * base_chunks);
+
+ info->map[0].end = 0x400000;
+ info->map[0].mask = 0xFFFFFF;
+ info->map[0].flags = MMAP_READ;
+ info->map[0].buffer = rom;
+ info->save_type = SAVE_NONE;
+ }
+}
-rom_info configure_rom_heuristics(uint8_t *rom)
+rom_info configure_rom_heuristics(uint8_t *rom, uint32_t rom_size, memmap_chunk const *base_map, uint32_t base_chunks)
{
rom_info info;
info.name = get_header_name(rom);
info.regions = get_header_regions(rom);
+ add_memmap_header(&info, rom, rom_size, base_map, base_chunks);
return info;
}
-rom_info configure_rom(tern_node *rom_db, void *vrom)
+rom_info configure_rom(tern_node *rom_db, void *vrom, uint32_t rom_size, memmap_chunk const *base_map, uint32_t base_chunks)
{
uint8_t product_id[GAME_ID_LEN+1];
uint8_t *rom = vrom;
@@ -102,7 +309,7 @@ rom_info configure_rom(tern_node *rom_db, void *vrom)
}
tern_node * entry = tern_find_prefix(rom_db, product_id);
if (!entry) {
- return configure_rom_heuristics(rom);
+ return configure_rom_heuristics(rom, rom_size, base_map, base_chunks);
}
rom_info info;
info.name = tern_find_ptr(entry, "name");
@@ -123,5 +330,18 @@ rom_info configure_rom(tern_node *rom_db, void *vrom)
if (!info.regions) {
info.regions = get_header_regions(rom);
}
+
+ tern_node *map = tern_find_prefix(entry, "map");
+ if (map) {
+ uint32_t map_count = tern_count(map);
+ if (map_count) {
+
+ } else {
+ add_memmap_header(&info, rom, rom_size, base_map, base_chunks);
+ }
+ } else {
+ add_memmap_header(&info, rom, rom_size, base_map, base_chunks);
+ }
+
return info;
}
generated by cgit v1.2.3 (git 2.25.1) at 2025-06-19 12:16:23 +0000