FAMAX

Floating-point absolute maximum. This instruction determines the maximum absolute value from floating-point elements of the first source vector and the corresponding floating-point elements of the second source vector, and places the results in the corresponding elements of the destination vector.

The behavior is as follows:

It has encodings from 2 classes: Half-precision and Single-precision and double-precision

Half-precision
(FEAT_FAMINMAX)

313029282726252423222120191817161514131211109876543210
0Q001110110Rm000111RnRd
Uaopcode

FAMAX <Vd>.<T>, <Vn>.<T>, <Vm>.<T>

if !IsFeatureImplemented(FEAT_FAMINMAX) then UNDEFINED; constant integer esize = 16; integer n = UInt(Rn); integer m = UInt(Rm); integer d = UInt(Rd); constant integer datasize = if Q == '1' then 128 else 64; integer elements = datasize DIV esize; boolean ismax = U == '0';

Single-precision and double-precision
(FEAT_FAMINMAX)

313029282726252423222120191817161514131211109876543210
0Q0011101x1Rm110111RnRd
Usizeopcode

FAMAX <Vd>.<T>, <Vn>.<T>, <Vm>.<T>

if !IsFeatureImplemented(FEAT_FAMINMAX) then UNDEFINED; if Q == '0' && size == '11' then UNDEFINED; constant integer esize = 8 << UInt(size); integer n = UInt(Rn); integer m = UInt(Rm); integer d = UInt(Rd); constant integer datasize = if Q == '1' then 128 else 64; integer elements = datasize DIV esize; boolean ismax = U == '0';

Assembler Symbols

<Vd>

Is the name of the SIMD&FP destination register, encoded in the "Rd" field.

<T>

For the half-precision variant: is an arrangement specifier, encoded in Q:

Q <T>
0 4H
1 8H

For the single-precision and double-precision variant: is an arrangement specifier, encoded in size<0>:Q:

size<0> Q <T>
0 0 2S
0 1 4S
1 0 RESERVED
1 1 2D
<Vn>

Is the name of the first SIMD&FP source register, encoded in the "Rn" field.

<Vm>

Is the name of the second SIMD&FP source register, encoded in the "Rm" field.

Operation

CheckFPAdvSIMDEnabled64(); bits(datasize) operand1 = V[n, datasize]; bits(datasize) operand2 = V[m, datasize]; bits(datasize) result; for e = 0 to elements-1 bits(esize) op1 = Elem[operand1, e, esize]; bits(esize) op2 = Elem[operand2, e, esize]; if ismax then Elem[result, e, esize] = FPAbsMax(op1, op2, FPCR); else Elem[result, e, esize] = FPAbsMin(op1, op2, FPCR); V[d, datasize] = result;


Internal version only: aarchmrs v2024-03_relA, pseudocode v2024-03_rel, sve v2024-03_rel ; Build timestamp: 2024-03-26T09:45

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