From e5bc9bc4dbd88d4b158b11c90cda202cd916baad Mon Sep 17 00:00:00 2001
From: Fabien Freling <public@ffreling.com>
Date: Sun, 22 Mar 2015 16:57:03 +0100
Subject: [PATCH] Use memory map instead of cartridge.

---
 src/cpu.ml    | 21 ++++++++++-----------
 src/memory.ml | 23 ++++++++++++++++++++++-
 src/oboy.ml   |  8 ++++----
 3 files changed, 36 insertions(+), 16 deletions(-)

diff --git a/src/cpu.ml b/src/cpu.ml
index cd0314d..8f42fc1 100644
--- a/src/cpu.ml
+++ b/src/cpu.ml
@@ -61,9 +61,9 @@ let split_2B x =
   let high = x / 256 |> char_of_int in
   (high, low)
 
-let read_2B b addr =
-  let low = Bytes.get b addr in
-  let high = Bytes.get b (addr + 1) in
+let read_2B m addr =
+  let low = Memory.get m addr in
+  let high = Memory.get m (addr + 1) in
   merge_bytes low high
 
 let inc_BC cpu =
@@ -73,12 +73,11 @@ let inc_BC cpu =
   cpu.reg.b <- high
 
 (** http://imrannazar.com/GameBoy-Z80-Opcode-Map *)
-let run cpu (cartridge: Cartridge.t) =
-  let data = cartridge.full_rom in
-  let n = Bytes.get data (cpu.reg.pc + 1) in
-  let nn = Bytes.get data (cpu.reg.pc + 2) in
+let run cpu (mem: Memory.map) =
+  let n = Memory.get mem (cpu.reg.pc + 1) in
+  let nn = Memory.get mem (cpu.reg.pc + 2) in
 (*  Hexa.print_slice cartridge.full_rom cpu.reg.pc (cpu.reg.pc + 7); *)
-  match Bytes.get data cpu.reg.pc with
+  match Memory.get mem cpu.reg.pc with
   | '\x00' -> printf "  NOP\n";
               inc_pc cpu 1; inc_cycles cpu 4
 
@@ -95,16 +94,16 @@ let run cpu (cartridge: Cartridge.t) =
               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
+  | '\xC3' -> let addr = read_2B mem (cpu.reg.pc + 1) in
               printf "  JP \t0x%04X\n" addr;
               cpu.reg.pc <- addr; inc_cycles cpu 16
 
   | '\xE0' -> printf "  LDH \t(0xFF%02X), A\n" (int_of_char n);
-              (* fixme *)
+              Memory.set mem (0xFF00 + (int_of_char n)) cpu.reg.a;
               inc_pc cpu 2; inc_cycles cpu 12
 
   | '\xF0' -> printf "  LDH \tA, (0xFF%02X)\n" (int_of_char n);
-              (* fixme *)
+              cpu.reg.a = Memory.get mem (0xFF00 + (int_of_char n));
               inc_pc cpu 2; inc_cycles cpu 12
 
   | '\xF3' -> printf "  DI\n";
diff --git a/src/memory.ml b/src/memory.ml
index 6351838..785c170 100644
--- a/src/memory.ml
+++ b/src/memory.ml
@@ -1,3 +1,5 @@
+open Bytes
+
 (** http://bgb.bircd.org/pandocs.htm#memorymap
     http://imrannazar.com/GameBoy-Emulation-in-JavaScript:-Memory *)
 
@@ -5,12 +7,31 @@ type map = {
   rom_bank_00 : bytes; (* cartridge, 16KB *)
   rom_bank_01 : bytes; (* additional bank, 16KB *)
   vram : bytes; (* Video RAM, 8KB *)
+  io : bytes; (* I/O ports *)
 }
 
 let init (cartridge: Cartridge.t) =
-  let open Bytes in
   {
     rom_bank_00 = sub cartridge.full_rom 0 0x4000;
     rom_bank_01 = create 0x4000;
     vram = create 0x2000;
+    io = create 0x0080;
   }
+
+let get_mem_bank mem addr =
+  match addr with
+  | x when x < 0x4000 -> mem.rom_bank_00, x
+  | x when x < 0x8000 -> mem.rom_bank_01, (x - 0x4000)
+  | x when x < 0xA000 -> mem.vram,  (x - 0x8000)
+  | x when x < 0xFF00 -> failwith "Unimplemented memory range."
+  | x when x < 0xFF80 -> mem.io, x - 0xFF00
+  | _ -> failwith "Invalid memory range."
+
+
+let get mem addr =
+  let m, x = get_mem_bank mem addr in
+  get m x
+
+let set mem addr c =
+  let m, x = get_mem_bank mem addr in
+  set m x c
diff --git a/src/oboy.ml b/src/oboy.ml
index 737d638..33f74be 100644
--- a/src/oboy.ml
+++ b/src/oboy.ml
@@ -1,8 +1,8 @@
 open Printf
 
-let rec run (cpu: Cpu.t) (cartridge: Cartridge.t) =
-  Cpu.run cpu cartridge;
-  run cpu cartridge
+let rec run (cpu: Cpu.t) (mem: Memory.map) =
+  Cpu.run cpu mem;
+  run cpu mem
 
 (** Power up sequence
     http://bgb.bircd.org/pandocs.htm#powerupsequence *)
@@ -16,7 +16,7 @@ let power_up cartridge =
 
     let cpu = Cpu.init_cpu in
     let mem = Memory.init cartridge in
-    run cpu cartridge
+    run cpu mem
 
 
 let () =