Game Boy C Emulator

• This Project Aims to simulate a GameBoy
• I started with Typescript but I thought it maybe more interesting to do it in C :)
• Current status: still working on it

Z80 Flags:

• Flag Register (F):

  • Zero: 0x80, set if the last operation produced a zeo result.
  • Substraction: 0x40, Set if the last operation was a substraction.
  • Half_carry: 0x20, Set if, in the result of the last operation, the lower half of the byte overflowed past 15.
  • Carry: 0x10, if the last op produced a result ; over 255 for addition or under 0 for substraction.

---

Implemented Instruction Set

Opcode	Operation	Implemented	Test Status
0x00	NOP	✅	✅
0x01	LD BC, d16	✅	❌
0x02	LD (BC), A	✅	❌
0x03	INC BC	✅	❌
0x04	INC B	✅	❌
0x05	DEC B	✅	❌
0x06	LD B, d8	✅	✅
0x07	RLCA	✅	❌
0x08	LD (a16), SP	❌	❌
0x09	ADD HL, BC	✅	❌
0x0A	LD A, (BC)	✅	❌
0x0B	DEC BC	✅	❌
0x0C	INC C	✅	❌
0x0D	DEC C	✅	❌
0x0E	LD C, d8	✅	❌
0x0F	RRCA	✅	❌
0x10	STOP	✅	❌
0x11	LD DE, d16	✅	❌
0x12	LD (DE), A	✅	❌
0x13	INC DE	✅	❌
0x14	INC D	✅	❌
0x15	DEC D	✅	❌
0x16	LD D, d8	✅	❌
0x17	RLA	✅	❌
0x18	JR r8	✅	❌
0x19	ADD HL, DE	✅	❌
0x1A	LD A, (DE)	✅	❌
0x1B	DEC DE	✅	❌
0x1C	INC E	✅	❌
0x1D	DEC E	✅	❌
0x1E	LD E, d8	✅	❌
0x1F	RRA	✅	❌
0x20	JR NZ, r8	✅	❌
0x21	LD HL, d16	✅	❌
0x22	LD (HL+), A	✅	❌
0x23	INC HL	✅	❌
0x24	INC H	✅	❌
0x25	DEC H	✅	❌
0x26	LD H, d8	✅	❌
0x27	DAA	✅	❌
0x28	JR Z, r8	✅	❌
0x29	ADD HL, HL	✅	❌
0x2A	LD A, (HL+)	✅	❌
0x2B	DEC HL	✅	❌
0x2C	INC L	✅	❌
0x2D	DEC L	✅	❌
0x2E	LD L, d8	✅	❌
0x2F	CPL	✅	❌
0x30	JR NC, r8	✅	❌
0x31	LD SP, d16	✅	❌
0x32	LD (HL-), A	✅	❌
0x33	INC SP	✅	❌
0x34	INC (HL)	✅	❌
0x35	DEC (HL)	✅	❌
0x36	LD (HL), d8	❌	❌
0x37	SCF	✅	❌
0x38	JR C, r8	✅	❌
0x39	ADD HL, SP	✅	❌
0x3A	LD A, (HL-)	❌	❌
0x3B	DEC SP	✅	❌
0x3C	INC A	✅	❌
0x3D	DEC A	✅	❌
0x3E	LD A, d8	✅	❌
0x3F	CCF	✅	❌
0x40	LD B, B	✅	❌
0x41	LD B, C	✅	✅
0x42	LD B, D	✅	❌
0x43	LD B, E	✅	❌
0x44	LD B, H	✅	❌
0x45	LD B, L	✅	❌
0x46	LD B, (HL)	❌	❌
0x47	LD B, A	✅	❌
0x48	LD C, B	✅	❌
0x49	LD C, C	✅	❌
0x4A	LD C, D	✅	❌
0x4B	LD C, E	✅	❌
0x4C	LD C, H	✅	❌
0x4D	LD C, L	✅	❌
0x4E	LD C, (HL)	❌	❌
0x4F	LD C, A	✅	❌
0x50	LD D, B	✅	❌
0x51	LD D, C	✅	❌
0x52	LD D, D	✅	❌
0x53	LD D, E	✅	❌
0x54	LD D, H	✅	❌
0x55	LD D, L	✅	❌
0x56	LD D, (HL)	❌	❌
0x57	LD D, A	✅	❌
0x58	LD E, B	✅	❌
0x59	LD E, C	✅	❌
0x5A	LD E, D	✅	❌
0x5B	LD E, E	✅	❌
0x5C	LD E, H	✅	❌
0x5D	LD E, L	✅	❌
0x5E	LD E, (HL)	❌	❌
0x5F	LD E, A	✅	❌
0x60	LD H, B	✅	❌
0x61	LD H, C	✅	❌
0x62	LD H, D	✅	❌
0x63	LD H, E	✅	❌
0x64	LD H, H	✅	❌
0x65	LD H, L	✅	❌
0x66	LD H, (HL)	❌	❌
0x67	LD H, A	✅	❌
0x68	LD L, B	✅	❌
0x69	LD L, C	✅	❌
0x6A	LD L, D	✅	❌
0x6B	LD L, E	✅	❌
0x6C	LD L, H	✅	❌
0x6D	LD L, L	✅	❌
0x6E	LD L, (HL)	❌	❌
0x6F	LD L, A	✅	❌
0x70	LD (HL), B	❌	❌
0x71	LD (HL), C	❌	❌
0x72	LD (HL), D	❌	❌
0x73	LD (HL), E	❌	❌
0x74	LD (HL), H	❌	❌
0x75	LD (HL), L	❌	❌
0x76	HALT	✅	❌
0x77	LD (HL), A	❌	❌
0x78	LD A, B	✅	❌
0x79	LD A, C	✅	❌
0x7A	LD A, D	✅	❌
0x7B	LD A, E	✅	❌
0x7C	LD A, H	✅	❌
0x7D	LD A, L	✅	❌
0x7E	LD A, (HL)	❌	❌
0x7F	LD A, A	✅	❌
0x80	ADD A, B	✅	❌
0x81	ADD A, C	✅	❌
0x82	ADD A, D	✅	❌
0x83	ADD A, E	✅	❌
0x84	ADD A, H	✅	❌
0x85	ADD A, L	✅	❌
0x86	ADD A, (HL)	❌	❌
0x87	ADD A, A	✅	❌
0x88	ADC A, B	✅	❌
0x89	ADC A, C	✅	❌
0x8A	ADC A, D	✅	❌
0x8B	ADC A, E	✅	❌
0x8C	ADC A, H	✅	❌
0x8D	ADC A, L	✅	❌
0x8E	ADC A, (HL)	❌	❌
0x8F	ADC A, A	✅	❌
0x90	SUB B	✅	❌
0x91	SUB C	✅	❌
0x92	SUB D	✅	❌
0x93	SUB E	✅	❌
0x94	SUB H	✅	❌
0x95	SUB L	✅	❌
0x96	SUB (HL)	❌	❌
0x97	SUB A	✅	❌
0x98	SBC A, B	✅	❌
0x99	SBC A, C	✅	❌
0x9A	SBC A, D	✅	❌
0x9B	SBC A, E	✅	❌
0x9C	SBC A, H	✅	❌
0x9D	SBC A, L	✅	❌
0x9E	SBC A, (HL)	❌	❌
0x9F	SBC A, A	✅	❌
0xA0	AND B	✅	❌
0xA1	AND C	✅	❌
0xA2	AND D	✅	❌
0xA3	AND E	✅	❌
0xA4	AND H	✅	❌
0xA5	AND L	✅	❌
0xA6	AND (HL)	❌	❌
0xA7	AND A	✅	❌
0xA8	XOR B	✅	❌
0xA9	XOR C	✅	❌
0xAA	XOR D	✅	❌
0xAB	XOR E	✅	❌
0xAC	XOR H	✅	❌
0xAD	XOR L	✅	❌
0xAE	XOR (HL)	❌	❌
0xAF	XOR A	✅	❌
0xB0	OR B	✅	❌
0xB1	OR C	✅	❌
0xB2	OR D	✅	❌
0xB3	OR E	✅	❌
0xB4	OR H	✅	❌
0xB5	OR L	✅	❌
0xB6	OR (HL)	❌	❌
0xB7	OR A	✅	❌
0xB8	CP B	✅	❌
0xB9	CP C	✅	❌
0xBA	CP D	✅	❌
0xBB	CP E	✅	❌
0xBC	CP H	✅	❌
0xBD	CP L	✅	❌
0xBE	CP (HL)	❌	❌
0xBF	CP A	✅	❌
0xC0	RET NZ	✅	❌
0xC1	POP BC	✅	❌
0xC2	JP NZ, a16	✅	❌
0xC3	JP a16	✅	❌
0xC4	CALL NZ, a16	✅	❌
0xC5	PUSH BC	✅	❌
0xC6	ADD A, d8	✅	❌
0xC7	RST 00H	❌	❌
0xC8	RET Z	✅	❌
0xC9	RET	✅	❌
0xCA	JP Z, a16	✅	❌
0xCB	PREFIX CB	✅	❌
0xCC	CALL Z, a16	✅	❌
0xCD	CALL a16	✅	❌
0xCE	ADC A, d8	✅	❌
0xCF	RST 08H	❌	❌
0xD0	RET NC	✅	❌
0xD1	POP DE	✅	❌
0xD2	JP NC, a16	✅	❌
0xD3	-	❌	❌
0xD4	CALL NC, a16	✅	❌
0xD5	PUSH DE	✅	❌
0xD6	SUB d8	✅	❌
0xD7	RST 10H	❌	❌
0xD8	RET C	✅	❌
0xD9	RETI	✅	❌
0xDA	JP C, a16	✅	❌
0xDB	-	❌	❌
0xDC	CALL C, a16	✅	❌
0xDD	-	❌	❌
0xDE	SBC A, d8	✅	❌
0xDF	RST 18H	❌	❌
0xE0	LDH (a8), A	❌	❌
0xE1	POP HL	✅	❌
0xE2	LD (C), A	❌	❌
0xE3	-	❌	❌
0xE4	-	❌	❌
0xE5	PUSH HL	✅	❌
0xE6	AND d8	✅	❌
0xE7	RST 20H	❌	❌
0xE8	ADD SP, r8	✅	❌
0xE9	JP (HL)	✅	❌
0xEA	LD (a16), A	✅	❌
0xEB	-	❌	❌
0xEC	-	❌	❌
0xED	-	❌	❌
0xEE	XOR d8	✅	❌
0xEF	RST 28H	❌	❌
0xF0	LDH A, (a8)	❌	❌
0xF1	POP AF	✅	❌
0xF2	LD A, (C)	❌	❌
0xF3	DI	✅	❌
0xF4	-	❌	❌
0xF5	PUSH AF	✅	❌
0xF6	OR d8	✅	❌
0xF7	RST 30H	❌	❌
0xF8	LD HL, SP+r8	✅	❌
0xF9	LD SP, HL	✅	❌
0xFA	LD A, (a16)	✅	❌
0xFB	EI	✅	❌
0xFC	-	❌	❌
0xFD	-	❌	❌
0xFE	CP d8	✅	❌
0xFF	RST 38H	❌	❌

CB-Prefixed Instruction Set

Opcode	Operation	Implemented	Test Status
0x00	RLC B	❌	❌
0x01	RLC C	❌	❌
0x02	RLC D	❌	❌
0x03	RLC E	❌	❌
0x04	RLC H	❌	❌
0x05	RLC L	❌	❌
0x06	RLC (HL)	❌	❌
0x07	RLC A	❌	❌
0x08	RRC B	❌	❌
0x09	RRC C	❌	❌
0x0A	RRC D	❌	❌
0x0B	RRC E	❌	❌
0x0C	RRC H	❌	❌
0x0D	RRC L	❌	❌
0x0E	RRC (HL)	❌	❌
0x0F	RRC A	❌	❌
0x10	RL B	❌	❌
0x11	RL C	❌	❌
0x12	RL D	❌	❌
0x13	RL E	❌	❌
0x14	RL H	❌	❌
0x15	RL L	❌	❌
0x16	RL (HL)	❌	❌
0x17	RL A	❌	❌
0x18	RR B	❌	❌
0x19	RR C	❌	❌
0x1A	RR D	❌	❌
0x1B	RR E	❌	❌
0x1C	RR H	❌	❌
0x1D	RR L	❌	❌
0x1E	RR (HL)	❌	❌
0x1F	RR A	❌	❌
0x20	SLA B	❌	❌
0x21	SLA C	❌	❌
0x22	SLA D	❌	❌
0x23	SLA E	❌	❌
0x24	SLA H	❌	❌
0x25	SLA L	❌	❌
0x26	SLA (HL)	❌	❌
0x27	SLA A	❌	❌
0x28	SRA B	❌	❌
0x29	SRA C	❌	❌
0x2A	SRA D	❌	❌
0x2B	SRA E	❌	❌
0x2C	SRA H	❌	❌
0x2D	SRA L	❌	❌
0x2E	SRA (HL)	❌	❌
0x2F	SRA A	❌	❌
0x30	SWAP B	❌	❌
0x31	SWAP C	❌	❌
0x32	SWAP D	❌	❌
0x33	SWAP E	❌	❌
0x34	SWAP H	❌	❌
0x35	SWAP L	❌	❌
0x36	SWAP (HL)	❌	❌
0x37	SWAP A	❌	❌
0x38	SRL B	❌	❌
0x39	SRL C	❌	❌
0x3A	SRL D	❌	❌
0x3B	SRL E	❌	❌
.
0x3C	SRL H	❌	❌
0x3D	SRL L	❌	❌
0x3E	SRL (HL)	❌	❌
0x3F	SRL A	❌	❌
0x40	BIT 0, B	❌	❌
0x41	BIT 0, C	❌	❌
0x42	BIT 0, D	❌	❌
0x43	BIT 0, E	❌	❌
0x44	BIT 0, H	❌	❌
0x45	BIT 0, L	❌	❌
0x46	BIT 0, (HL)	❌	❌
0x47	BIT 0, A	❌	❌
0x48	BIT 1, B	❌	❌
0x49	BIT 1, C	❌	❌
0x4A	BIT 1, D	❌	❌
0x4B	BIT 1, E	❌	❌
0x4C	BIT 1, H	❌	❌
0x4D	BIT 1, L	❌	❌
0x4E	BIT 1, (HL)	❌	❌
0x4F	BIT 1, A	❌	❌
0x50	BIT 2, B	❌	❌
0x51	BIT 2, C	❌	❌
0x52	BIT 2, D	❌	❌
0x53	BIT 2, E	❌	❌
0x54	BIT 2, H	❌	❌
0x55	BIT 2, L	❌	❌
0x56	BIT 2, (HL)	❌	❌
0x57	BIT 2, A	❌	❌
0x58	BIT 3, B	❌	❌
0x59	BIT 3, C	❌	❌
0x5A	BIT 3, D	❌	❌
0x5B	BIT 3, E	❌	❌
0x5C	BIT 3, H	❌	❌
0x5D	BIT 3, L	❌	❌
0x5E	BIT 3, (HL)	❌	❌
0x5F	BIT 3, A	❌	❌
0x60	BIT 4, B	❌	❌
0x61	BIT 4, C	❌	❌
0x62	BIT 4, D	❌	❌
0x63	BIT 4, E	❌	❌
0x64	BIT 4, H	❌	❌
0x65	BIT 4, L	❌	❌
0x66	BIT 4, (HL)	❌	❌
0x67	BIT 4, A	❌	❌
0x68	BIT 5, B	❌	❌
0x69	BIT 5, C	❌	❌
0x6A	BIT 5, D	❌	❌
0x6B	BIT 5, E	❌	❌
0x6C	BIT 5, H	❌	❌
0x6D	BIT 5, L	❌	❌
0x6E	BIT 5, (HL)	❌	❌
0x6F	BIT 5, A	❌	❌
0x70	BIT 6, B	❌	❌
0x71	BIT 6, C	❌	❌
0x72	BIT 6, D	❌	❌
0x73	BIT 6, E	❌	❌
0x74	BIT 6, H	❌	❌
0x75	BIT 6, L	❌	❌
0x76	BIT 6, (HL)	❌	❌
0x77	BIT 6, A	❌	❌
0x78	BIT 7, B	❌	❌
0x79	BIT 7, C	❌	❌
0x7A	BIT 7, D	❌	❌
0x7B	BIT 7, E	❌	❌
0x7C	BIT 7, H	❌	❌
0x7D	BIT 7, L	❌	❌
0x7E	BIT 7, (HL)	❌	❌
0x7F	BIT 7, A	❌	❌
0x80	RES 0, B	❌	❌
0x81	RES 0, C	❌	❌
0x82	RES 0, D	❌	❌
0x83	RES 0, E	❌	❌
0x84	RES 0, H	❌	❌
0x85	RES 0, L	❌	❌
0x86	RES 0, (HL)	❌	❌
0x87	RES 0, A	❌	❌
0x88	RES 1, B	❌	❌
0x89	RES 1, C	❌	❌
0x8A	RES 1, D	❌	❌
0x8B	RES 1, E	❌	❌
0x8C	RES 1, H	❌	❌
0x8D	RES 1, L	❌	❌
0x8E	RES 1, (HL)	❌	❌
0x8F	RES 1, A	❌	❌
0x90	RES 2, B	❌	❌
0x91	RES 2, C	❌	❌
0x92	RES 2, D	❌	❌
0x93	RES 2, E	❌	❌
0x94	RES 2, H	❌	❌
0x95	RES 2, L	❌	❌
0x96	RES 2, (HL)	❌	❌
0x97	RES 2, A	❌	❌
0x98	RES 3, B	❌	❌
0x99	RES 3, C	❌	❌
0x9A	RES 3, D	❌	❌
0x9B	RES 3, E	❌	❌
0x9C	RES 3, H	❌	❌
0x9D	RES 3, L	❌	❌
0x9E	RES 3, (HL)	❌	❌
0x9F	RES 3, A	❌	❌
0xA0	RES 4, B	❌	❌
0xA1	RES 4, C	❌	❌
0xA2	RES 4, D	❌	❌
0xA3	RES 4, E	❌	❌
0xA4	RES 4, H	❌	❌
0xA5	RES 4, L	❌	❌
0xA6	RES 4, (HL)	❌	❌
0xA7	RES 4, A	❌	❌
0xA8	RES 5, B	❌	❌
0xA9	RES 5, C	❌	❌
0xAA	RES 5, D	❌	❌
0xAB	RES 5, E	❌	❌
0xAC	RES 5, H	❌	❌
0xAD	RES 5, L	❌	❌
0xAE	RES 5, (HL)	❌	❌
0xAF	RES 5, A	❌	❌
0xB0	RES 6, B	❌	❌
0xB1	RES 6, C	❌	❌
0xB2	RES 6, D	❌	❌
0xB3	RES 6, E	❌	❌
0xB4	RES 6, H	❌	❌
0xB5	RES 6, L	❌	❌
0xB6	RES 6, (HL)	❌	❌
0xB7	RES 6, A	❌	❌
0xB8	RES 7, B	❌	❌
0xB9	RES 7, C	❌	❌
0xBA	RES 7, D	❌	❌
0xBB	RES 7, E	❌	❌
0xBC	RES 7, H	❌	❌
0xBD	RES 7, L	❌	❌
0xBE	RES 7, (HL)	❌	❌
0xBF	RES 7, A	❌	❌
0xC0	SET 0, B	❌	❌
0xC1	SET 0, C	❌	❌
0xC2	SET 0, D	❌	❌
0xC3	SET 0, E	❌	❌
0xC4	SET 0, H	❌	❌
0xC5	SET 0, L	❌	❌
0xC6	SET 0, (HL)	❌	❌
0xC7	SET 0, A	❌	❌
0xC8	SET 1, B	❌	❌
0xC9	SET 1, C	❌	❌
0xCA	SET 1, D	❌	❌
0xCB	SET 1, E	❌	❌
0xCC	SET 1, H	❌	❌
0xCD	SET 1, L	❌	❌
0xCE	SET 1, (HL)	❌	❌
0xCF	SET 1, A	❌	❌
0xD0	SET 2, B	❌	❌
0xD1	SET 2, C	❌	❌
0xD2	SET 2, D	❌	❌
0xD3	SET 2, E	❌	❌
0xD4	SET 2, H	❌	❌
0xD5	SET 2, L	❌	❌
0xD6	SET 2, (HL)	❌	❌
0xD7	SET 2, A	❌	❌
0xD8	SET 3, B	❌	❌
0xD9	SET 3, C	❌	❌
0xDA	SET 3, D	❌	❌
0xDB	SET 3, E	❌	❌
0xDC	SET 3, H	❌	❌
0xDD	SET 3, L	❌	❌
0xDE	SET 3, (HL)	❌	❌
0xDF	SET 3, A	❌	❌
0xE0	SET 4, B	❌	❌
0xE1	SET 4, C	❌	❌
0xE2	SET 4, D	❌	❌
0xE3	SET 4, E	❌	❌
0xE4	SET 4, H	❌	❌
0xE5	SET 4, L	❌	❌
0xE6	SET 4, (HL)	❌	❌
0xE7	SET 4, A	❌	❌
0xE8	SET 5, B	❌	❌
0xE9	SET 5, C	❌	❌
0xEA	SET 5, D	❌	❌
0xEB	SET 5, E	❌	❌
0xEC	SET 5, H	❌	❌
0xED	SET 5, L	❌	❌
0xEE	SET 5, (HL)	❌	❌
0xEF	SET 5, A	❌	❌
0xF0	SET 6, B	❌	❌
0xF1	SET 6, C	❌	❌
0xF2	SET 6, D	❌	❌
0xF3	SET 6, E	❌	❌
0xF4	SET 6, H	❌	❌
0xF5	SET 6, L	❌	❌
0xF6	SET 6, (HL)	❌	❌
0xF7	SET 6, A	❌	❌
0xF8	SET 7, B	❌	❌
0xF9	SET 7, C	❌	❌
0xFA	SET 7, D	❌	❌
0xFB	SET 7, E	❌	❌
0xFC	SET 7, H	❌	❌
0xFD	SET 7, L	❌	❌
0xFE	SET 7, (HL)	❌	❌
0xFF	SET 7, A	❌	❌

Ressources:

Some resources I'm using to build this emulator.

• Pandocs
• The Linoscope Machine Page
• Imran Nazar's blog