Gather lower bits from positions selected by bitmask
This instruction gathers bits in each element of the first source vector from the bit positions indicated by non-zero bits in the corresponding mask element of the second source vector to the lowest-numbered contiguous bits of the corresponding destination element, preserving their order, and sets the remaining higher-numbered bits to zero. This instruction is unpredicated.
ID_AA64ZFR0_EL1.BitPerm indicates whether this instruction is implemented.
This instruction is illegal when executed in Streaming SVE mode, unless FEAT_SME_FA64 is implemented and enabled.
| 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
| 0 | 1 | 0 | 0 | 0 | 1 | 0 | 1 | size | 0 | Zm | 1 | 0 | 1 | 1 | 0 | 0 | Zn | Zd | |||||||||||||
if !HaveSVE() || !HaveSVE2BitPerm() then UNDEFINED; constant integer esize = 8 << UInt(size); integer n = UInt(Zn); integer m = UInt(Zm); integer d = UInt(Zd);
| <Zd> |
Is the name of the destination scalable vector register, encoded in the "Zd" field. |
| <T> |
Is the size specifier,
encoded in
|
| <Zn> |
Is the name of the first source scalable vector register, encoded in the "Zn" field. |
| <Zm> |
Is the name of the second source scalable vector register, encoded in the "Zm" field. |
CheckNonStreamingSVEEnabled(); constant integer VL = CurrentVL; constant integer elements = VL DIV esize; bits(VL) data = Z[n, VL]; bits(VL) mask = Z[m, VL]; bits(VL) result; for e = 0 to elements - 1 Elem[result, e, esize] = BitExtract(Elem[data, e, esize], Elem[mask, e, esize]); Z[d, VL] = result;
If PSTATE.DIT is 1:
Internal version only: aarchmrs v2023-12_rel, pseudocode v2023-12_rel, sve v2023-12_rel ; Build timestamp: 2023-12-15T16:46
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