Base Instructions | SIMD&FP Instructions | SVE Instructions | SME Instructions | Index by Encoding | Shared Pseudocode | Proprietary Notice

## FAC<cc>

Floating-point absolute compare vectors

Compare active absolute values of floating-point elements in the first source vector with corresponding absolute values of elements in the second source vector, and place the boolean results of the specified comparison in the corresponding elements of the destination predicate. Inactive elements in the destination predicate register are set to zero. Does not set the condition flags.

<cc> | Comparison
--- | ---
GE | greater than or equal
GT | greater than
LE | less than or equal
LT | less than

This instruction is used by the pseudo-instructions FACLE, and FACLT.

It has encodings from 2 classes: Greater than and Greater than or equal

### Greater than

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 | 1 | 1 | 0 | 0 | 1 | 0 | 1 | size | 0 | Zm | 1 | 1 | 1 | Pg | Zn | 1 | Pd

####

FACGT <Pd>.<T>, <Pg>/Z, <Zn>.<T>, <Zm>.<T>

if !HaveSVE() && !HaveSME() then UNDEFINED; if size == '00' then UNDEFINED; constant integer esize = 8 << UInt(size); integer g = UInt(Pg); integer n = UInt(Zn); integer m = UInt(Zm); integer d = UInt(Pd); SVECmp op = Cmp_GT;

### Greater than or equal

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 | 1 | 1 | 0 | 0 | 1 | 0 | 1 | size | 0 | Zm | 1 | 1 | 0 | Pg | Zn | 1 | Pd

####

FACGE <Pd>.<T>, <Pg>/Z, <Zn>.<T>, <Zm>.<T>

if !HaveSVE() && !HaveSME() then UNDEFINED; if size == '00' then UNDEFINED; constant integer esize = 8 << UInt(size); integer g = UInt(Pg); integer n = UInt(Zn); integer m = UInt(Zm); integer d = UInt(Pd); SVECmp op = Cmp_GE;

### 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 | RESERVED
01 | H
10 | S
11 | D

<Pg> | Is the name of the governing scalable predicate register P0-P7, encoded in the "Pg" field.

<Zn> | Is the name of the first source scalable vector register, encoded in the "Zn" field.

<Zm> | Is the name of the second source scalable vector register, encoded in the "Zm" field.

### Operation

CheckSVEEnabled(); constant integer VL = CurrentVL; constant integer PL = VL DIV 8; constant integer elements = VL 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 bits(esize) element1 = Elem[operand1, e, esize]; bits(esize) element2 = Elem[operand2, e, esize]; boolean res; case op of when Cmp_GE res = FPCompareGE(FPAbs(element1), FPAbs(element2), FPCR[]); when Cmp_GT res = FPCompareGT(FPAbs(element1), FPAbs(element2), FPCR[]); bit pbit = if res then '1' else '0'; Elem[result, e, psize] = ZeroExtend(pbit, psize); else Elem[result, e, psize] = ZeroExtend('0', psize); P[d, PL] = result;

### Operational information

If FEAT_SME is implemented and the PE is in Streaming SVE mode, then any subsequent instruction which is dependent on the predicate register written by this instruction might be significantly delayed.

Base Instructions | SIMD&FP Instructions | SVE Instructions | SME Instructions | Index by Encoding | Shared Pseudocode | Proprietary Notice

Internal version only: isa v33.64, AdvSIMD v29.12, pseudocode v2023-06_rel, sve v2023-06_rel ; Build timestamp: 2023-07-04T19:42

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