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ABS

Absolute value (vector). This instruction calculates the absolute value of each vector element in the source SIMD&FP register, puts the result into a vector, and writes the vector to the destination SIMD&FP register.

Depending on the settings in the CPACR_EL1, CPTR_EL2, and CPTR_EL3 registers, and the current Security state and Exception level, an attempt to execute the instruction might be trapped.

It has encodings from 2 classes: Scalar and Vector

Scalar

313029282726252423222120191817161514131211109876543210
01011110size100000101110RnRd
U

Scalar

ABS <V><d>, <V><n>

integer d = UInt(Rd); integer n = UInt(Rn); if size != '11' then ReservedValue(); integer esize = 8 << UInt(size); integer datasize = esize; integer elements = 1; boolean neg = (U == '1');

Vector

313029282726252423222120191817161514131211109876543210
0Q001110size100000101110RnRd
U

Vector

ABS <Vd>.<T>, <Vn>.<T>

integer d = UInt(Rd); integer n = UInt(Rn); if size:Q == '110' then ReservedValue(); integer esize = 8 << UInt(size); integer datasize = if Q == '1' then 128 else 64; integer elements = datasize DIV esize; boolean neg = (U == '1');

Assembler Symbols

<V> Is a width specifier, encoded in size:
size<V>
0xRESERVED
10RESERVED
11D
Is a width specifier, encoded in size:
size<V>
0xRESERVED
10RESERVED
11D
<d>

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

<n>

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

<Vd>

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

<T> Is an arrangement specifier, encoded in size:Q:
sizeQ<T>
0008B
00116B
0104H
0118H
1002S
1014S
110RESERVED
1112D
Is an arrangement specifier, encoded in size:Q:
sizeQ<T>
0008B
00116B
0104H
0118H
1002S
1014S
110RESERVED
1112D
<Vn>

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

Operation

CheckFPAdvSIMDEnabled64(); bits(datasize) operand = V[n]; bits(datasize) result; integer element; for e = 0 to elements-1 element = SInt(Elem[operand, e, esize]); if neg then element = -element; else element = Abs(element); Elem[result, e, esize] = element<esize-1:0>; V[d] = result;

Operational information

If PSTATE.DIT is 1:


Internal version only: isa v29.05v27.02, AdvSIMD v26.0, pseudocode v35.3v34.2.2 ; Build timestamp: 2018-06-16T092018-03-28T19:4555

Copyright © 2010-2018 ARM Limited or its affiliates. All rights reserved. This document is Non-Confidential.

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