added support for MBC2 games, fixing Wave Race and more

index.html

@@ -112,7 +112,7 @@ <h1 class="hide">Super Game Boy Border Injector</h1>
 
 
 <footer>
-	Super Game Boy Border Injector v1.2.1b<br/>
+	Super Game Boy Border Injector v1.3<br/>
 	made with <span class="love" title="Super love">Super <img src="web-injector/assets/octicon_heart_color.svg" alt="love" class="octicon" /></span> by <a href="https://www.marcrobledo.com" target="_blank">Marc Robledo</a>
 	<img src="web-injector/assets/octicon_github.svg" alt="GitHub logo" class="octicon" /> <a href="https://github.com/marcrobledo/super-game-boy-border-injector/"  target="_blank">See sourcecode in GitHub</a>
 </footer>

src/main.asm

@@ -40,7 +40,11 @@ boot_hook:
 	push	af
 
 	ld		a, BANK(sgb_init)
-	ld		[rROMB0], a
+	IF MBC == 2
+		ld		[$2100], a
+	ELSE
+		ld		[rROMB0], a
+	ENDC
 
 	IF MBC == 1 && SGB_CODE_BANK>=$20
 		ld		a, ((BANK(sgb_init) & %01100000) >> 5)
@@ -49,7 +53,11 @@ boot_hook:
 
 	call	sgb_init
 
-	ld		[rROMB0], a
+	IF MBC == 2
+		ld		[$2100], a
+	ELSE
+		ld		[rROMB0], a
+	ENDC
 	IF MBC == 1 && SGB_CODE_BANK>=$20
 		xor		a
 		ld		[rRAMB], a

src/settings.asm

@@ -31,6 +31,7 @@ DEF BANK0_FREE_SPACE EQU $3ff0
 ; (see more here: https://gbdev.io/pandocs/MBCs.html)
 ; MBC needs to be here specified in these special cases:
 ; - MBC1 + expanded ROM to 1Mb or bigger (Zelda Link's Awakening [non-DX])
+; - MBC2 (bank to switch has to be written to $2100 instead of $2000: https://gbdev.io/pandocs/MBC2.html#registers)
 ; - (to-do!) MBC5 + expanded ROM to 8Mb
 ; other cases will just ignore this value
 ; keep in mind that, in these special cases, the hook subroutine will grow

web-injector/app/assembled-code.js

@@ -48,6 +48,20 @@ export const ASSEMBLED_HOOK_INFO=[
 			0xf1,								//pop	af
 			0xc3, 'entry_point_low', 'entry_point_high' //jp original_entry_point
 		]
+	},
+	//MBC2
+	//rom bank must be written to 0x2100
+	{
+		id:'mbc2',
+		code:[
+			0xf5,						//push	af
+			0x3e, 'rom_bank_number',	//ld	a, sgb_init_bank
+			0xea, 0x00, 0x21,			//ld	[0x2100], a
+			0xcd, 0x00, 0x40,			//call	0x4000
+			0xea, 0x00, 0x21,			//ld	[0x2100], a
+			0xf1,						//pop	af
+			0xc3, 'entry_point_low', 'entry_point_high' //jp original_entry_point
+		]
 	}
 ];
 ASSEMBLED_HOOK_INFO.forEach(function(assembledInfo){

web-injector/app/main.js

@@ -508,6 +508,8 @@ function buildROM(){
 			}
 
 			assembledHookInfo=getAssembledHookInfo('mbc1_extra');
+		}else if(currentRomType.mbc===2){
+			assembledHookInfo=getAssembledHookInfo('mbc2');
 		}else{
 			assembledHookInfo=getAssembledHookInfo('default');
 		}