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Read ROM size.

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This commit is contained in:
Fabien Freling 2015-02-23 16:10:40 +01:00
parent b0df091425
commit fdb5744d01
2 changed files with 35 additions and 6 deletions
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31
src/cartridge.ml
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@ -3,6 +3,8 @@ open Printf
(** http://bgb.bircd.org/pandocs.htm#thecartridgeheader *)
exception Read_error
type memory_bank_controller =
| ROM_ONLY
| MBC1
@ -10,9 +12,9 @@ type memory_bank_controller =
type t = {
nintendo_logo : bytes;
title : string;
(* mem_type : memory_bank_controller;
(* mem_type : memory_bank_controller; *)
rom_size : int;
ram_size : int;
(* ram_size : int;
header_checksum : bytes;
global_checksum : bytes; *)
}
@ -25,7 +27,22 @@ let check_nintendo_logo cartridge =
\xBB\xBB\x67\x63\x6E\x0E\xEC\xCC\xDD\xDC\x99\x9F\xBB\xB9\x33\x3E" in
(Bytes.compare cartridge.nintendo_logo reference) == 0
exception Read_error
(** ROM size is expressed in KB *)
let get_ROM_size b =
match Bytes.get b 0 |> int_of_char with
| 0x00 -> 32 (* no ROM banking *)
| 0x01 -> 64 (* 4 banks *)
| 0x02 -> 128 (* 8 banks *)
| 0x03 -> 256 (* 16 banks *)
| 0x04 -> 512 (* 32 banks *)
| 0x05 -> 1000 (* 64 banks - only 63 banks used by MBC1 *)
| 0x06 -> 2000 (* 128 banks - only 125 banks used by MBC1 *)
| 0x07 -> 4000 (* 256 banks *)
| 0x52 -> 1100 (* 72 banks *)
| 0x53 -> 1200 (* 80 banks *)
| 0x54 -> 1500 (* 96 banks *)
| _ -> raise Read_error
let read_cartridge file =
try
@ -47,8 +64,14 @@ let read_cartridge file =
then raise Read_error;
let title = Bytes.to_string title_b in
let size_b = Bytes.create 1 in
let _ = lseek fd 4 SEEK_CUR in
if (read fd size_b 0 1) != 1
then raise Read_error;
let rom_size = get_ROM_size size_b in
Unix.close fd;
Some { nintendo_logo; title }
Some { nintendo_logo; title; rom_size }
with Read_error -> Unix.close fd; None

10
src/oboy.ml
View file

@ -1,9 +1,15 @@
(** Power up sequence *)
open Printf
(** Power up sequence
http://bgb.bircd.org/pandocs.htm#powerupsequence *)
let power_up cartridge =
(** Nintendo logo scrolling *)
if not (Cartridge.check_nintendo_logo cartridge)
then print_endline "Invalid ROM."
else print_endline "Valid ROM."
else
print_endline "Valid ROM.";
printf "ROM size: %iKB\n" cartridge.rom_size
let () =
if Array.length Sys.argv < 2