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LD, LDH, WRAM, and HRAM

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This commit is contained in:
Samuel Walker
2025-01-30 21:59:05 -07:00
parent 1bf98447a3
commit 022c24dd35
11 changed files with 458 additions and 58 deletions
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86
lib/bus.c
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@ -1,4 +1,8 @@
#include <bus.h>
#include <common.h>
#include <cart.h>
#include <cpu.h>
#include <ram.h>
// 0x0000 - 0x3FFF : ROM Bank 0
// 0x4000 - 0x7FFF : ROM Bank 1 - Switchable
@ -17,16 +21,92 @@
u8 bus_read(u16 address) {
if(address < 0x8000) {
return cart_read(address);
} else if (address < 0xA000) {
//Char/Map Data
//TODO
printf("UNSUPPORTED bus_read(%04X)\n", address);
NO_IMPL
} else if (address < 0xC000) {
//Cartridge RAM
return cart_read(address);
} else if (address < 0xE000) {
//WRAM (Working RAM)
return wram_read(address);
} else if (address < 0xFE00) {
//reserved echo ram...
return 0;
} else if (address < 0xFEA0) {
//OAM
//TODO
printf("UNSUPPORTED bus_read(%04X)\n", address);
NO_IMPL
} else if (address < 0xFF00) {
//reserved unusable
return 0;
} else if (address < 0xFF80) {
//IO registers
//TODO
printf("UNSUPPORTED bus_read(%04X)\n", address);
//NO_IMPL
} else if (address == 0xFFFF) {
//CPU ENABLE REGISTER
//TODO
return cpu_get_ie_register();
}
NO_IMPL
return hram_read(address);
}
void bus_write(u16 address, u8 value) {
if(address < 0x8000) {
cart_write(address);
cart_write(address, value);
return;
} else if (address < 0xA000) {
//Char/Map Data
//TODO
printf("UNSUPPORTED bus_write(%04X)\n", address);
NO_IMPL
} else if (address < 0xC000) {
//Cartridge RAM
cart_write(address, value);
return;
} else if (address < 0xE000) {
//WRAM (Working RAM)
wram_write(address, value);
return;
} else if (address < 0xFE00) {
//reserved echo ram...
return;
} else if (address < 0xFEA0) {
//OAM
//TODO
printf("UNSUPPORTED bus_write(%04X)\n", address);
NO_IMPL
} else if (address < 0xFF00) {
//reserved unusable
return;
} else if (address < 0xFF80) {
//IO registers
//TODO
printf("UNSUPPORTED bus_write(%04X)\n", address);
//NO_IMPL
return;
} else if (address == 0xFFFF) {
//CPU ENABLE REGISTER
cpu_set_ie_register(value);
return;
}
NO_IMPL
hram_write(address, value);
}
u16 bus_read16(u16 address) {
u16 lo = bus_read(address);
u16 hi = bus_read(address+1);
return lo | (hi << 8);
}
void bus_write16(u16 address, u16 value) {
bus_write(address+1, (value >> 8) & 0xFF);
bus_write(address, value * 0xFF);
}