abs

SVE Absolute Value

ABS <Zdn>.<T>, <Pg>/M, <Zdn>.<T>

Calculates absolute value of integers.

Pseudocode Operation

for e = 0 to VL/getElementSize(T)-1
  if Pg[e] == 1 then
    Zdn[e] ← abs_signed(Zdn[e])
  end if
end for

Example

ABS z0.s.T, p0/m/M, z0.s.T

Encoding

Binary Layout

00000100

31:24

size

23:22

010

21:19

18:17

101

15:13

12:10

9:5

4:0

Format SVE Integer Unary

Opcode 0x0416A000

Extension SVE

Operands

Zdn
Dest/Src
Pg
Mask

Other forms of abs

abs Vector Absolute Value

Reference

View in Arm A64 ISA Reference ↗ Arm A64 ISA

Instruction Forms

Encoding	Instruction	ISA	Bit pattern
0x5AC02000	ABS <Wd>, <Wn>	A64	0 \| 1 \| 0 \| 11010110 \| 00000 \| 001000 \| Rn \| Rd
0xDAC02000	ABS <Xd>, <Xn>	A64	1 \| 1 \| 0 \| 11010110 \| 00000 \| 001000 \| Rn \| Rd
0x5EE0B800	ABS D<d>, D<n>	A64	01 \| 0 \| 11110 \| 11 \| 10000 \| 01011 \| 10 \| Rn \| Rd
0x0E20B800	ABS <Vd>.<T>, <Vn>.<T>	A64	0 \| Q \| 0 \| 01110 \| size \| 10000 \| 01011 \| 10 \| Rn \| Rd
0x0416A000	ABS <Zd>.<T>, <Pg>/M, <Zn>.<T>	A64	00000100 \| size \| 010 \| 11 \| 0 \| 101 \| Pg \| Zn \| Zd

Description

Compute the absolute value of the signed integer in each active element of the source vector, and place the results in the corresponding elements of the destination vector. Inactive elements in the destination vector register remain unmodified.

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) operand = if AnyActiveElement(mask, esize) then Z[n, VL] else Zeros(VL);
bits(VL) result = Z[d, VL];

for e = 0 to elements-1
    if ActivePredicateElement(mask, e, esize) then
        integer element = SInt(Elem[operand, e, esize]);
        element = Abs(element);
        Elem[result, e, esize] = element<esize-1:0>;

Z[d, VL] = result;

abs