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

BRKN, BRKNS

Propagate break to next partition.

If the last active element of the first source predicate is false then set the destination predicate to all-false. Otherwise leaves the destination and second source predicate unchanged. Inactive elements in the destination predicate register are set to zero. Optionally sets the First (N), None (Z), !Last (C) condition flags based on the predicate result, and the V flag to zero.

It has encodings from 2 classes: Not setting the condition flags and Setting the condition flags

Not setting the condition flags

if !HaveSVE() then UNDEFINED;
integer g = UInt(Pg);
integer n = UInt(Pn);
integer dm = UInt(Pdm);
boolean setflags = FALSE;

Setting the condition flags

if !HaveSVE() then UNDEFINED;
integer g = UInt(Pg);
integer n = UInt(Pn);
integer dm = UInt(Pdm);
boolean setflags = TRUE;

Assembler Symbols

CheckSVEEnabled();
bits(PL) mask = P[g];
bits(PL) operand1 = P[n];
bits(PL) operand2 = P[dm];
bits(PL) result;

if LastActive(mask, operand1, 8) == '1' then
    result = operand2;
else
    result = Zeros();

if setflags then
    PSTATE.<N,Z,C,V> = PredTest(Ones(PL), result, 8);
P[dm] = result;