Unsigned saturating decrement vector by count of true predicate elements
Counts the number of true elements in the source predicate and then uses the result to decrement all destination vector elements. The results are saturated to the element unsigned integer range.
The predicate size specifier may be omitted in assembler source code, but this is deprecated and will be prohibited in a future release of the architecture.
| 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 | 1 | 0 | 0 | 1 | 0 | 1 | size | 1 | 0 | 1 | 0 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | Pm | Zdn | ||||||||
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if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then UNDEFINED; if size == '00' then UNDEFINED; constant integer esize = 8 << UInt(size); constant integer m = UInt(Pm); constant integer dn = UInt(Zdn); constant boolean unsigned = TRUE;
| <Zdn> |
Is the name of the source and destination scalable vector register, encoded in the "Zdn" field. |
| <T> |
Is the size specifier,
encoded in
|
| <Pm> |
Is the name of the source scalable predicate register, encoded in the "Pm" field. |
CheckSVEEnabled(); constant integer VL = CurrentVL; constant integer PL = VL DIV 8; constant integer elements = VL DIV esize; constant bits(VL) operand1 = Z[dn, VL]; constant bits(PL) operand2 = P[m, PL]; bits(VL) result; integer count = 0; for e = 0 to elements-1 if ActivePredicateElement(operand2, e, esize) then count = count + 1; for e = 0 to elements-1 constant integer element = Int(Elem[operand1, e, esize], unsigned); (Elem[result, e, esize], -) = SatQ(element - count, esize, unsigned); Z[dn, VL] = result;
This instruction might be immediately preceded in program order by a MOVPRFX instruction. The MOVPRFX must conform to all of the following requirements, otherwise the behavior of the MOVPRFX and this instruction is constrained unpredictable:
Internal version only: aarchmrs v2024-03_relA, pseudocode v2024-03_rel, sve v2024-03_rel ; Build timestamp: 2024-03-26T09:45
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