WHILELO

While incrementing unsigned scalar lower than scalar

Generate a predicate that starting from the lowest numbered element is true while the incrementing value of the first, unsigned scalar operand is lower than the second scalar operand and false thereafter up to the highest numbered element.

The full width of the scalar operands is significant for the purposes of comparison, and the full width first operand is incremented by one for each destination predicate element, irrespective of the predicate result element size. The first general-purpose source register is not itself updated.

The predicate result is placed in the predicate destination register. Sets the First (N), None (Z), !Last (C) condition flags based on the predicate result, and the V flag to zero.

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00100101size1Rm000sf11Rn0Pd
Ulteq

WHILELO <Pd>.<T>, <R><n>, <R><m>

if !HaveSVE() && !HaveSME() then UNDEFINED; integer esize = 8 << UInt(size); integer rsize = 32 << UInt(sf); integer n = UInt(Rn); integer m = UInt(Rm); integer d = UInt(Pd); boolean unsigned = TRUE; SVECmp op = Cmp_LT;

Assembler Symbols

<Pd>

Is the name of the destination scalable predicate register, encoded in the "Pd" field.

<T>

Is the size specifier, encoded in size:

size <T>
00 B
01 H
10 S
11 D
<R>

Is a width specifier, encoded in sf:

sf <R>
0 W
1 X
<n>

Is the number [0-30] of the source general-purpose register or the name ZR (31), encoded in the "Rn" field.

<m>

Is the number [0-30] of the source general-purpose register or the name ZR (31), encoded in the "Rm" field.

Operation

CheckSVEEnabled(); integer elements = VL DIV esize; bits(PL) mask = Ones(PL); bits(rsize) operand1 = X[n]; bits(rsize) operand2 = X[m]; bits(PL) result; boolean last = TRUE; for e = 0 to elements-1 boolean cond; case op of when Cmp_LT cond = (Int(operand1, unsigned) < Int(operand2, unsigned)); when Cmp_LE cond = (Int(operand1, unsigned) <= Int(operand2, unsigned)); last = last && cond; ElemP[result, e, esize] = if last then '1' else '0'; operand1 = operand1 + 1; PSTATE.<N,Z,C,V> = PredTest(mask, result, esize); P[d] = result;

Operational information

If FEAT_SVE2 is enabled or FEAT_SME is enabled, then when PSTATE.DIT is 1:


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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