nmatch
SVE No Match
Detects if elements in Zn match *none* of the elements in Zm.
Pseudocode Operation
No pseudocode available.
Encoding
Operands
-
Pd
Predicate Dest -
Pg
Mask -
Zn
Haystack -
Zm
Needle
Related
More in SVE2
Reference
Instruction Forms
| Encoding | Instruction | ISA | Bit pattern | ||
|---|---|---|---|---|---|
| 0x45208010 | NMATCH <Pd>.<T>, <Pg>/Z, <Zn>.<T>, <Zm>.<T> | A64 | 01000101 | size | 1 | Zm | 100 | Pg | Zn | 1 | Pd |
Description
This instruction compares each active 8-bit or 16-bit character in the first source vector with all of the characters in the corresponding 128-bit segment of the second source vector. Where the first source element detects no matching characters in the second segment it places true in the corresponding element of the destination predicate, otherwise false. Inactive elements in the destination predicate register are set to zero. Sets the First (N), None (Z), !Last (C) condition flags based on the predicate result, and the V flag to zero. This instruction is illegal when executed in Streaming SVE mode, unless FEAT_SME_FA64 is implemented and enabled.
Operation
CheckNonStreamingSVEEnabled();
constant integer VL = CurrentVL;
constant integer PL = VL DIV 8;
constant integer elements = VL DIV esize;
constant integer eltspersegment = 128 DIV esize;
bits(PL) mask = P[g, PL];
bits(VL) operand1 = if AnyActiveElement(mask, esize) then Z[n, VL] else Zeros(VL);
bits(VL) operand2 = if AnyActiveElement(mask, esize) then Z[m, VL] else Zeros(VL);
bits(PL) result;
constant integer psize = esize DIV 8;
for e = 0 to elements-1
if ActivePredicateElement(mask, e, esize) then
integer segmentbase = e - (e MOD eltspersegment);
Elem[result, e, psize] = ZeroExtend('1', psize);
bits(esize) element1 = Elem[operand1, e, esize];
for i = segmentbase to (segmentbase + eltspersegment) - 1
bits(esize) element2 = Elem[operand2, i, esize];
if element1 == element2 then
Elem[result, e, psize] = ZeroExtend('0', psize);
else
Elem[result, e, psize] = ZeroExtend('0', psize);
PSTATE.<N,Z,C,V> = PredTest(mask, result, esize);
P[d, PL] = result;