16 bit format:
| PrCSR | (15..11) | 10 | 9 | 8 | (7..1) | 0 |
|---|---|---|---|---|---|---|
| 0 | predidx | zero0 | inv0 | i/f | regidx | ffirst0 |
| 1 | predidx | zero1 | inv1 | i/f | regidx | ffirst1 |
| 2 | predidx | zero2 | inv2 | i/f | regidx | ffirst2 |
| 3 | predidx | zero3 | inv3 | i/f | regidx | ffirst3 |
Note: predidx=x0, zero=1, inv=1 is a RESERVED encoding. Its use must generate an illegal instruction trap.
8 bit format:
| PrCSR | 7 | 6 | 5 | (4..0) |
|---|---|---|---|---|
| 0 | zero0 | inv0 | i/f | regnum |
Mapping from 8 to 16 bit format, the table becomes:
| PrCSR | (15..11) | 10 | 9 | 8 | (7..1) | 0 |
|---|---|---|---|---|---|---|
| 0 | x9 | zero0 | inv0 | i/f | regnum | ff=0 |
| 1 | x10 | zero1 | inv1 | i/f | regnum | ff=0 |
| 2 | x11 | zero2 | inv2 | i/f | regnum | ff=0 |
| 3 | x12 | zero3 | inv3 | i/f | regnum | ff=0 |