Merge #82

82: Remove dependency on gbafix r=Lokathor a=ketsuban

As per #80 this is the minimum you have to do to remove gbafix from the toolchain. I ended up doing this myself so that I could load the ELF binary directly into no$gba and use its excellent debugger.

There's no reason for the "main unit code" to ever change (the `0x96` byte before it is a fixed value) but changing the game title, game code, maker code, device type or software version will necessitate recalculating the complement check, and I didn't feel like working out if I could get the assembler to do that for me.

Co-authored-by: Thomas Winwood <twwinwood@gmail.com>

Makefile.toml

@@ -45,9 +45,6 @@ fn main() -> std::io::Result<()> {
         &format!("target/thumbv4-none-agb/release/examples/{}",name),
         &format!("target/{}.gba",name)])
         .output().expect("failed to objcopy!");
-      std::process::Command::new("gbafix").args(
-        &[&format!("target/{}.gba",name)])
-        .output().expect("failed to gbafix!");
     }
   }
   Ok(())

crt0.s

@@ -2,8 +2,46 @@
 __start:
     b .Linit
 
-    @ ROM header will be filled in by gbafix
+    @ ROM header
-    .fill 188, 1, 0
+    .byte 0x24,0xff,0xae,0x51,0x69,0x9a,0xa2,0x21,0x3d,0x84,0x82,0x0a,0x84,0xe4,0x09,0xad
+    .byte 0x11,0x24,0x8b,0x98,0xc0,0x81,0x7f,0x21,0xa3,0x52,0xbe,0x19,0x93,0x09,0xce,0x20
+    .byte 0x10,0x46,0x4a,0x4a,0xf8,0x27,0x31,0xec,0x58,0xc7,0xe8,0x33,0x82,0xe3,0xce,0xbf
+    .byte 0x85,0xf4,0xdf,0x94,0xce,0x4b,0x09,0xc1,0x94,0x56,0x8a,0xc0,0x13,0x72,0xa7,0xfc
+    .byte 0x9f,0x84,0x4d,0x73,0xa3,0xca,0x9a,0x61,0x58,0x97,0xa3,0x27,0xfc,0x03,0x98,0x76
+    .byte 0x23,0x1d,0xc7,0x61,0x03,0x04,0xae,0x56,0xbf,0x38,0x84,0x00,0x40,0xa7,0x0e,0xfd
+    .byte 0xff,0x52,0xfe,0x03,0x6f,0x95,0x30,0xf1,0x97,0xfb,0xc0,0x85,0x60,0xd6,0x80,0x25
+    .byte 0xa9,0x63,0xbe,0x03,0x01,0x4e,0x38,0xe2,0xf9,0xa2,0x34,0xff,0xbb,0x3e,0x03,0x44
+    .byte 0x78,0x00,0x90,0xcb,0x88,0x11,0x3a,0x94,0x65,0xc0,0x7c,0x63,0x87,0xf0,0x3c,0xaf
+    .byte 0xd6,0x25,0xe4,0x8b,0x38,0x0a,0xac,0x72,0x21,0xd4,0xf8,0x07
+
+    @ game title
+    .byte 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00
+
+    @ game code
+    .byte 0x00,0x00,0x00,0x00
+
+    @ maker code
+    .byte 0x00,0x00
+
+    .byte 0x96
+
+    @ main unit code
+    .byte 0x00
+
+    @ device type (0x00 retail, 0x80 debug)
+    .byte 0x00
+
+    @ reserved
+    .byte 0x00,0x00,0x00,0x00,0x00,0x00,0x00
+
+    @ software version
+    .byte 0x00
+
+    @ complement check
+    .byte 0x51
+
+    @ reserved area
+    .space 2
 
 .Linit:
     @ Set address of user IRQ handler