Super FX Opcode Matrices

The Super FX has two prefix flags called ALT1 and ALT2 that alter the way the GSU interprets opcodes. These four opcode matrices will show which instruction actually runs depending on how those prefix flags are set.

ALT1 = 0, ALT2 = 0

	x0	x1	x2	x3	x4	x5	x6	x7	x8	x9	xA	xB	xC	xD	xE	xF
0x	STOP	NOP	CACHE	LSR	ROL	BRA	BGE	BLT	BNE	BEQ	BPL	BMI	BCC	BCS	BVC	BVS
1x
2x
3x													LOOP	ALT1	ALT2	ALT3
4x													PLOT	SWAP	COLOR	NOT
5x
6x
7x	MERGE
8x
9x	SBK	LINK #1	LINK #2	LINK #3	LINK #4	SEX	ASR	ROR							LOB	FMULT
Ax
Bx
Cx	HIB
Dx																GETC
Ex																GETB
Fx

ALT1 = 0, ALT2 = 1

	x0	x1	x2	x3	x4	x5	x6	x7	x8	x9	xA	xB	xC	xD	xE	xF
0x	STOP	NOP	CACHE	LSR	ROL	BRA	BGE	BLT	BNE	BEQ	BPL	BMI	BCC	BCS	BVC	BVS
1x
2x
3x													LOOP	ALT1	ALT2	ALT3
4x													PLOT	SWAP	COLOR	NOT
5x
6x
7x	MERGE
8x
9x	SBK	LINK #1	LINK #2	LINK #3	LINK #4	SEX	ASR	ROR							LOB	FMULT
Ax
Bx
Cx	HIB
Dx																GETC
Ex																GETBL
Fx

ALT1 = 1, ALT2 = 0

	x0	x1	x2	x3	x4	x5	x6	x7	x8	x9	xA	xB	xC	xD	xE	xF
0x	STOP	NOP	CACHE	LSR	ROL	BRA	BGE	BLT	BNE	BEQ	BPL	BMI	BCC	BCS	BVC	BVS
1x
2x
3x													LOOP	ALT1	ALT2	ALT3
4x													PLOT	SWAP	CMODE	NOT
5x	ADC R0	ADC R1	ADC R2	ADC R3	ADC R4	ADC R5	ADC R6	ADC R7	ADC R8	ADC R9	ADC R10	ADC R11	ADC R12	ADC R13	ADC R14	ADC R15
6x
7x	MERGE
8x
9x	SBK	LINK #1	LINK #2	LINK #3	LINK #4	SEX	DIV2	ROR							LOB	FMULT
Ax
Bx
Cx	HIB
Dx																GETC
Ex																GETBH
Fx

ALT1 = 1, ALT2 = 1

	x0	x1	x2	x3	x4	x5	x6	x7	x8	x9	xA	xB	xC	xD	xE	xF
0x	STOP	NOP	CACHE	LSR	ROL	BRA	BGE	BLT	BNE	BEQ	BPL	BMI	BCC	BCS	BVC	BVS
1x
2x
3x													LOOP	ALT1	ALT2	ALT3
4x													PLOT	SWAP	COLOR ?	NOT
5x
6x
7x	MERGE	BIC #1	BIC #2	BIC #3	BIC #4	BIC #5	BIC #6	BIC #7	BIC #8	BIC #9	BIC #10	BIC #11	BIC #12	BIC #13	BIC #14	BIC #15
8x
9x	SBK	LINK #1	LINK #2	LINK #3	LINK #4	SEX	DIV2 ?	ROR							LOB	FMULT
Ax
Bx
Cx	HIB
Dx																GETC
Ex																GETBS
Fx