Arm® A64 Instruction Set Architecture: Future Architecture Technologies in the A architecture profile

NMATCH

Detect no matching elements, setting the condition flags.

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.

if !HaveSVE2() then UNDEFINED;
if size == '1x' then UNDEFINED;
integer esize = 8 << UInt(size);
integer g = UInt(Pg);
integer d = UInt(Pd);
integer n = UInt(Zn);
integer m = UInt(Zm);

Assembler Symbols

CheckSVEEnabled();
integer elements = VL DIV esize;
integer eltspersegment = 128 DIV esize;
bits(PL) mask = P[g];
bits(VL) operand1 = Z[n];
bits(VL) operand2 = Z[m];
bits(PL) result;

for e = 0 to elements-1
    if ElemP[mask, e, esize] == '1' then
        integer segmentbase = e - (e MOD eltspersegment);
        ElemP[result, e, esize] = '1';
        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
                ElemP[result, e, esize] = '0';
    else
        ElemP[result, e, esize] = '0';

PSTATE.<N,Z,C,V> = PredTest(mask, result, esize);
P[d] = result;