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 | ||||||||
| D | U | ||||||||||||||||||||||||||||||
if !HaveSVE() && !HaveSME() then UNDEFINED; if size == '00' then UNDEFINED; integer esize = 8 << UInt(size); integer m = UInt(Pm); integer dn = UInt(Zdn); 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(); integer elements = VL DIV esize; bits(VL) operand1 = Z[dn]; bits(PL) operand2 = P[m]; bits(VL) result; integer count = 0; for e = 0 to elements-1 if ElemP[operand2, e, esize] == '1' then count = count + 1; for e = 0 to elements-1 integer element = Int(Elem[operand1, e, esize], unsigned); (Elem[result, e, esize], -) = SatQ(element - count, esize, unsigned); Z[dn] = result;
This instruction might be immediately preceded in program order by a MOVPRFX instruction. The MOVPRFX instruction must conform to all of the following requirements, otherwise the behavior of the MOVPRFX and this instruction is unpredictable:
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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