all repos — mgba @ c640819179b9ef6f441bd97327634bd70c8842a8

mGBA Game Boy Advance Emulator

GB: Downgrade DMG-only ROMs from CGB mode even without boot ROM
Vicki Pfau vi@endrift.com
Fri, 20 Nov 2020 00:35:52 -0800
commit

c640819179b9ef6f441bd97327634bd70c8842a8

parent

bf611e01f238b3366dcde7a5f176a0a9d198c520

2 files changed, 6 insertions(+), 0 deletions(-)

jump to
M CHANGES → CHANGES 
@@ -17,6 +17,7 @@ - ARM: Fix ALU reading PC after shifting
  - ARM: Fix STR storing PC after address calculation
  - ARM: Fix Addressing mode 1 shifter on rs == pc (fixes mgba.io/i/1926)
  - GB: Partially fix timing for skipped BIOS
+ - GB: Downgrade DMG-only ROMs from CGB mode even without boot ROM
  - GB Audio: Fix serializing sweep time
  - GB MBC: Fix MBC1 mode changing behavior
  - GB MBC: Fix some MBC3 bit masking
M src/gb/gb.c → src/gb/gb.c 
@@ -489,6 +489,11 @@ struct SM83Core* cpu = gb->cpu;
 	const struct GBCartridge* cart = (const struct GBCartridge*) &gb->memory.rom[0x100];
 	int nextDiv = 0;
 
+	if (gb->model >= GB_MODEL_CGB && !(cart->cgb & 0x80)) {
+		gb->model = GB_MODEL_DMG;
+		GBVideoDisableCGB(&gb->video);
+	}
+
 	switch (gb->model) {
 	case GB_MODEL_AUTODETECT: // Silence warnings
 		gb->model = GB_MODEL_DMG;