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
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x0
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x1
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x2
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x3
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x6
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x7
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x9
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xD
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xF
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ALT1 |
ALT2 |
ALT3
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| 5x |
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| 7x |
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| 8x |
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| Fx |
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ALT1 = 0, ALT2 = 1
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x0
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x1
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x2
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x3
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x4
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x5
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x6
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x7
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x8
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x9
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xA
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xD
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xE
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xF
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| 0x |
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| 1x |
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| 2x |
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| 3x |
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ALT1 |
ALT2 |
ALT3
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| 7x |
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| 8x |
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ALT1 = 1, ALT2 = 0
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x0
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x1
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x2
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x3
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x4
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x5
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x6
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x7
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x8
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x9
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xA
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xB
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xC
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xD
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xE
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xF
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| 0x |
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| 1x |
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| 2x |
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| 3x |
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ALT1 |
ALT2 |
ALT3
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| 4x |
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| 5x |
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| 6x |
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| 7x |
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| Ex |
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| Fx |
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ALT1 = 1, ALT2 = 1
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x0
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x1
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x2
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x3
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x4
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x5
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x6
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x7
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x8
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x9
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xA
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xB
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xC
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xD
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xE
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xF
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| 0x |
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| 1x |
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| 2x |
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| 3x |
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ALT1 |
ALT2 |
ALT3
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| 4x |
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| 5x |
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| 6x |
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| 7x |
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| 8x |
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| 9x |
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| Ax |
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| Bx |
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| Cx |
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| Dx |
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| Ex |
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| Fx |
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