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Add CPU instructions.

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This commit is contained in:
Fabien Freling 2015-02-28 00:25:10 +01:00
parent b2c7e7b947
commit 0f83810230
1 changed files with 49 additions and 7 deletions
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56
src/cpu.ml
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@ -53,16 +53,58 @@ let inc_pc cpu count =
let inc_cycles cpu count = let inc_cycles cpu count =
cpu.cycles <- cpu.cycles + count cpu.cycles <- cpu.cycles + count
let merge_bytes low high =
(int_of_char high) * 256 + (int_of_char low)
let split_2B x =
let low = x mod 256 |> char_of_int in
let high = x / 256 |> char_of_int in
(high, low)
let read_2B b addr = let read_2B b addr =
let low = Bytes.get b addr in let low = Bytes.get b addr in
let high = Bytes.get b (addr + 1) in let high = Bytes.get b (addr + 1) in
(int_of_char high) * 256 + (int_of_char low) merge_bytes low high
let inc_BC cpu =
let v = merge_bytes cpu.reg.c cpu.reg.b in
let low, high = split_2B (v + 1) in
cpu.reg.c <- low;
cpu.reg.b <- high
(** http://imrannazar.com/GameBoy-Z80-Opcode-Map *) (** http://imrannazar.com/GameBoy-Z80-Opcode-Map *)
let run cpu (cartridge: Cartridge.t) = let run cpu (cartridge: Cartridge.t) =
(* Hexa.print_slice cartridge.full_rom cpu.reg.pc (cpu.reg.pc + 7) ~width:16; *) let data = cartridge.full_rom in
match Bytes.get cartridge.full_rom cpu.reg.pc with let n = Bytes.get data (cpu.reg.pc + 1) in
| '\x00' -> printf " nop\n"; inc_pc cpu 1; inc_cycles cpu 4 let nn = Bytes.get data (cpu.reg.pc + 2) in
| '\xC3' -> let addr = read_2B cartridge.full_rom (cpu.reg.pc + 1) in (* Hexa.print_slice cartridge.full_rom cpu.reg.pc (cpu.reg.pc + 7); *)
printf " jp 0x%02x\n" addr; cpu.reg.pc <- addr; inc_cycles cpu 16 match Bytes.get data cpu.reg.pc with
| _ as x -> eprintf "OpCode %02X\n" (int_of_char x); failwith "Unimplemented opcode." | '\x00' -> printf " NOP\n";
inc_pc cpu 1; inc_cycles cpu 4
| '\x03' -> printf " INC \tBC\n";
inc_BC cpu;
inc_pc cpu 1; inc_cycles cpu 8
| '\x3E' -> printf " LD \tA, 0x%02X\n" (int_of_char n);
cpu.reg.a <- n;
inc_pc cpu 2; inc_cycles cpu 8
| '\xAF' -> printf " XOR \tA, A\n";
let int_A = int_of_char cpu.reg.a in
cpu.reg.a <- char_of_int @@ int_A lxor int_A;
inc_pc cpu 1; inc_cycles cpu 4
| '\xC3' -> let addr = read_2B data (cpu.reg.pc + 1) in
printf " JP \t0x%04X\n" addr;
cpu.reg.pc <- addr; inc_cycles cpu 16
| '\xE0' -> printf " LDH \t(0x%02X), A\n" (int_of_char n);
(* fixme *)
inc_pc cpu 2; inc_cycles cpu 12
| '\xF3' -> printf " DI\n";
(* fixme *)
inc_pc cpu 1; inc_cycles cpu 4
| _ as x -> eprintf "opcode %02X\n" (int_of_char x); failwith "Unimplemented opcode."