Extract element after last to general-purpose register
If there is an active element then extract the element after the last active element modulo the number of elements from the final source vector register. If there are no active elements, extract element zero. Then zero-extend and place the extracted element in the destination general-purpose register.
| 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 | 0 | 0 | 0 | 0 | 1 | 0 | 1 | size | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 1 | Pg | Zn | Rd | |||||||||||
| B | |||||||||||||||||||||||||||||||
if !HaveSVE() && !HaveSME() then UNDEFINED; integer esize = 8 << UInt(size); integer rsize = if esize < 64 then 32 else 64; integer g = UInt(Pg); integer n = UInt(Zn); integer d = UInt(Rd); boolean isBefore = FALSE;
| <R> |
Is a width specifier,
encoded in
|
| <d> |
Is the number [0-30] of the destination general-purpose register or the name ZR (31), encoded in the "Rd" field. |
| <Pg> |
Is the name of the governing scalable predicate register P0-P7, encoded in the "Pg" field. |
| <Zn> |
Is the name of the source scalable vector register, encoded in the "Zn" field. |
| <T> |
Is the size specifier,
encoded in
|
CheckSVEEnabled(); integer elements = VL DIV esize; bits(PL) mask = P[g]; bits(VL) operand = Z[n]; bits(rsize) result; integer last = LastActiveElement(mask, esize); if isBefore then if last < 0 then last = elements - 1; else last = last + 1; if last >= elements then last = 0; result = ZeroExtend(Elem[operand, last, esize]); X[d] = result;
If FEAT_SME is implemented and the PE is in Streaming SVE mode, then any subsequent instruction which is dependent on the general-purpose register written by this instruction might be significantly delayed.
Internal version only: isa v33.11seprel, AdvSIMD v29.05, pseudocode v2021-09_rel, sve v2021-09_rc3d ; Build timestamp: 2021-10-06T11:41
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