elif Word[30:31] = 0b00 return 32
else return 64
```
+
+# alternative encoding (3)
+
+derived from <https://bugs.libre-soc.org/show_bug.cgi?id=924#c20>
+
+In order for `Rc` and similar fields to not move for 32-bit instructions, bits
+`28:29` are used as the main encoding bits instead of `30:31`.
+
+space saving measures: EXT2xx is half the size
+
+## length decoding algorithm
+```
+if PREFIX[0:5] = 1 then return 64
+else if PREFIX[0:5] = 9 then
+ if PREFIX[28:29] = 3 then
+ if PREFIX[26:27] = 3 then return 64
+ else return 32
+ else return 64
+else return 32
+```
+
+## short table
+```
+|0 |6 |11 |16 |21 |22 |26 |28|29|30 |31 |32|33 |38 |
+| 9| SVRM[0:21] | 0| 0| SVRM[22:23]| EXT0xx insn | SVP64 ext0xx
+| 9| SVRM[0:21] | 0| 1| SVRM[22:23]| EXT0xx insn | SVP64Single ext0xx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| 0| EXT2xx insn | SVP64 ext2xx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| 1| EXT2xx insn | SVP64Single ext2xx
+| 9| - | 00| 1| 1| - | N/A | scalar 32-bit
+| 9| - | 01| 1| 1| - | N/A | scalar 32-bit
+| 9| - | 10| 1| 1| - | N/A | scalar 32-bit
+| 9| - | 11| 1| 1| - | scalar 64-bit
+| 9| RT| RA| RB| OE| XO| 00| 1| 1| XO | Rc| N/A | XO-form 32-bit
+| 9| RT| RA| RB| XO | 00| 1| 1| XO | Rc| N/A | X-form 32-bit
+| 9| RS| RA| sh| XO | 00| 1| 1| sh | Rc| N/A | XS-form 32-bit
+```
+
+## SVP64Single in SFFS
+
+important note: SFFS implementations that don't implement SVP64 can still
+implement EXT2xx instructions by using the SVP64Single encoding with SVRM=0,
+no other SVP64 state needs to be implemented to do that.
+(TODO: double check that)
+
+## full table
+
+note: I mostly stashed stuff in EXT2xx, so the scalar 32-bit space is still
+mostly free, most the instructions I wanted in the scalar 32-bit space took
+up too much room. I didn't allocate XO values in EXT2xx yet since there's
+plenty of space (32 POs equivalent)
+
+note: setvl is split into a 32-bit insn with a common subset of settings and
+a full 64-bit insn with all the settings; svstep is 32-bit
+
+note: fmv/fcvt are 32-bit ops, so you can see how they easily fit around bits
+26-29 which are used to distinguish from SVP64 prefixes.
+
+```
+|0 |6 |11 |16 |21 |22 |26 |28|29|30 |31 |32|33 |38 |
+| 9| SVRM[0:21] | 0| 0| SVRM[22:23]| EXT0xx insn | SVP64 ext0xx
+| 9| SVRM[0:21] | 0| 1| SVRM[22:23]| EXT0xx insn | SVP64Single ext0xx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| 0| EXT2xx insn | SVP64 ext2xx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| 1| EXT2xx insn | SVP64Single ext2xx
+| 9| - | 00| 1| 1| - | N/A | scalar 32-bit
+| 9| - | 01| 1| 1| - | N/A | scalar 32-bit
+| 9| - | 10| 1| 1| - | N/A | scalar 32-bit
+| 9| - | 11| 1| 1| - | scalar 64-bit
+| 9| RT| RA| RB| OE| XO| 00| 1| 1| XO | Rc| N/A | XO-form 32-bit
+| 9| RT| RA| RB| XO | 00| 1| 1| XO | Rc| N/A | X-form 32-bit
+| 9| RS| RA| sh| XO | 00| 1| 1| sh | Rc| N/A | XS-form 32-bit
+
+|0 |6 |11 |16 |21 |22 |26 |28|29|30 |31 |32|33 |38 |
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lbzup
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lbzupx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lhzup
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lhzupx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lhaup
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lhaupx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lwzup
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lwzupx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lwaupx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | ldup
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | ldupx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stbup
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stbupx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | sthup
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | sthupx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stwup
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stwupx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stdup
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stdupx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lfdu
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lfsup
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lfdupx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lsdupx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stfdup
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stfsup
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stfdupx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stfsupx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lbzuspx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lhzuspx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lhauspx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lwzuspx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lwauspx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lduspx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stbuspx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | sthuspx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stwuspx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stduspx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lfdupsx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lsdupsx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stfdupsx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stfsupsx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lbzsx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lbzusx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lhzsx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lhzusx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lhasx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lhausx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lwzsx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lwzusx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lwasx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lwausx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | ldsx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | ldusx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lhbrsx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lwbrsx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | ldbrsx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stbsx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stbusx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | sthsx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | sthusx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stwsx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stwusx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stdsx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stdusx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | sthbrsx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stwbrsx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stdbrsx
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lfsxs
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lfsuxs
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lfdxs
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lfduxs
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lfiwaxs
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | lfiwzxs
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stfsxs
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stfsuxs
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stfdxs
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stfduxs
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | stfiwxs
+
+|0 |6 |11 |16 |21 |22 |26 |28|29|30 |31 |32|33 |38 |
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | grevlut
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | grevluti
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | ternlogi
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | crternlogi
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | binlut
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | crbinlut
+
+|0 |6 |11 |14 |26 |28|29|30 |32 |
+| 9|FRT|mode| XO | 11| 1| 1| XO | imm32 | fli 64-bit
+
+|0 |6 |11 |16 |21 |23 |26 |28|29|30 |31 |32|33 |38 |
+| 9| RT| RA| RB| sm|000| 00| 1| 1| 0 | Rc| N/A | shadd
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | shadduw
+| 9| RT| RA| RB| sm|000| 00| 1| 1| 1 | Rc| N/A | shaddw
+
+|0 |6 |11 |16 |21 |22 |26 |28|29|30 |31 |32|33 |38 |
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | absdu
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | avgadd
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | minmax
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | absaccs
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | absaccu
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | bmask
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | cprop
+
+|0 |6 |11 |16 |21 |22 |26 |28|29|30 |31 |32|33 |38 |
+| 9| RT| RA| SVi |001| 00| 1| 1| vs | Rc| N/A | setvl (common 32-bit, ms=vs, vf=0)
+| 9| TBD | 11| 1| 1| TBD | setvl (full 64-bit)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | svremap
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | svshape
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | svshape2
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | svindex
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | mv.swizzle
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fmv.swizzle
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | crrweird
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | mfcrweird
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | mtcrrweird
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | mtcrweird
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | crweirder
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | mcrfm
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fptstp(s)
+
+|0 |6 |11 |13 |16 |21 |22 |26 |28|29|30 |31 |32|33 |38 |
+| 9| RT| 11|111| SVi |010| 00| 1| 1| vf | Rc| N/A | svstep
+| 9| RT| 10|111| FRB |010| 00| 1| 1| 0 | Rc| N/A | fmvtg
+| 9| RT| 10|111| FRB |010| 00| 1| 1| 1 | Rc| N/A | fmvtgs
+| 9|FRT| 01|111| RB |010| 00| 1| 1| 0 | Rc| N/A | fmvfg
+| 9|FRT| 01|111| RB |010| 00| 1| 1| 1 | Rc| N/A | fmvfgs
+| 9|FRT| IT|110| RB |010| 00| 1| 1| 0 | Rc| N/A | fcvtfg
+| 9|FRT| IT|110| RB |010| 00| 1| 1| 1 | Rc| N/A | fcvtfgs
+| 9| RT| IT|CVM| FRB |010| 00| 1| 1| 0 | Rc| N/A | fcvttg
+| 9|- | - |0-5| - |010| 00| 1| 1| 1 | Rc| N/A | *reserved*
+
+|0 |6 |11 |16 |21 |22 |26 |28|29|30 |31 |32|33 |38 |
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | dsld
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | dsrd
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | maddedu
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | maddedus
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | divmod2du
+
+|0 |6 |11 |16 |21 |22 |26 |28|29|30 |31 |32|33 |38 |
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | ffadd(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | ffsub(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | ffmul(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | ffdiv(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fdmadd(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | ffmadd(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | ffmsub(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | ffnmadd(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | ffnmsub(s)
+
+|0 |6 |11 |16 |21 |22 |26 |28|29|30 |31 |32|33 |38 |
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fsin(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fcos(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | ftan(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fasin(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | facos(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fatan(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fsinpi(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fcospi(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | ftanpi(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fasinpi(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | facospi(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fatanpi(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fsinh(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fcosh(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | ftanh(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fasinh(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | facosh(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fatanh(s)
+
+|0 |6 |11 |16 |21 |22 |26 |28|29|30 |31 |32|33 |38 |
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | frsqrt(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fcbrt(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | frecip(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fexp2m1(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | flog2p1(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fexp2(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | flog2(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fexpm1(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | flogp1(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fexp(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | flog(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fexp10m1(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | flog10p1(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fexp10(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | flog10(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fatan2(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fatan2pi(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fpow(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fpown(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fpowr(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | frootn(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fhypot(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fminmax
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fmod(s)
+| 9| SVRM[0:21] | 1| 0| SVRM[22:23]| -| TBD | fremainder(s)
+```
projects / libreriscv.git / commitdiff