Implemented CGB-only check

Author: Hacktix

gb8.sav

@@ -1,5 +1,6 @@
 EmuScreenPtrVRAM           EQU $9842
 GameTitlePtrVRAM           EQU $99AA
+NonCGBPtrVRAM              EQU $98A2
 
 CursorTileNo               EQU $AB
 

inc/gb8.inc

@@ -27,6 +27,9 @@ SECTION "Entry Point", ROM0[$100]
 
 SECTION "Main", ROM0[$150]
 Main::
+    ; Store initial value of L in RAM
+    ld [wInitialRegA], a
+
     ; Wait for VBlank, disable LCD
     ldh a, [rLY]
 	cp SCRN_Y
@@ -47,5 +50,42 @@ Main::
     call InitPalettes
     call InitFont
 
+    ; Check if running in CGB mode
+    ld a, [wInitialRegA]
+    cp BOOTUP_A_CGB
+    jp nz, ScreenNonCGB
+
     ; Jump to Selection Menu Initialization
-    jp StartSelectionMenu
+    jp StartSelectionMenu
+
+ScreenNonCGB::
+    ; Initialize DMG Palette
+    ld a, %11010100
+    ld [rBGP], a
+
+    ; Print CGB-only text to screen
+    ld hl, (NonCGBPtrVRAM)
+    ld de, strNonCGB1
+    call PrintString
+    ld hl, (NonCGBPtrVRAM + $40)
+    ld de, strNonCGB2
+    call PrintString
+    ld hl, (NonCGBPtrVRAM + $80)
+    ld de, strNonCGB3
+    call PrintString
+
+    ; Initialize LCD and clear IF/IE
+    xor a
+    ldh [rIF], a
+    ldh [rIE], a
+    ld a, LCDCF_ON | LCDCF_BGON | LCDCF_BG8000
+    ldh [rLCDC], a
+    ei
+    nop 
+
+    ; HALT infinitely
+    halt
+
+strNonCGB1: db "THIS SOFTWARE IS", 0
+strNonCGB2: db "INTENDED FOR USE", 0
+strNonCGB3: db "ON GAMEBOY COLOR", 0

src/main.asm

@@ -37,4 +37,7 @@ wSelectionPage::      db
 wSelectionCursorPos:: db
 wInputCooldown::      db
 wPageTitles::         db
-wAllowInput::         db
+wAllowInput::         db
+
+SECTION "Other Variables", WRAM0
+wInitialRegA:: db