SQRSHRUNT

Signed saturating rounding shift right unsigned narrow by immediate (top)

Shift each signed integer value in the source vector elements right by an immediate value, and place the rounded results in the odd-numbered half-width destination elements, leaving the even-numbered elements unchanged. Each result element is saturated to the half-width N-bit element's unsigned integer range 0 to (2N)-1. The immediate shift amount is an unsigned value in the range 1 to number of bits per element. This instruction is unpredicated.

313029282726252423222120191817161514131211109876543210
010001010tszh1tszlimm3000011ZnZd
URT

SQRSHRUNT <Zd>.<T>, <Zn>.<Tb>, #<const>

if !HaveSVE2() && !HaveSME() then UNDEFINED; bits(3) tsize = tszh:tszl; integer esize; case tsize of when '000' UNDEFINED; when '001' esize = 8; when '01x' esize = 16; when '1xx' esize = 32; integer n = UInt(Zn); integer d = UInt(Zd); integer shift = (2 * esize) - UInt(tsize:imm3);

Assembler Symbols

<Zd>

Is the name of the destination scalable vector register, encoded in the "Zd" field.

<T>

Is the size specifier, encoded in tszh:tszl:

tszh tszl <T>
0 00 RESERVED
0 01 B
0 1x H
1 xx S
<Zn>

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

<Tb>

Is the size specifier, encoded in tszh:tszl:

tszh tszl <Tb>
0 00 RESERVED
0 01 H
0 1x S
1 xx D
<const>

Is the immediate shift amount, in the range 1 to number of bits per element, encoded in "tsz:imm3".

Operation

CheckSVEEnabled(); integer elements = VL DIV (2 * esize); bits(VL) operand = Z[n]; bits(VL) result = Z[d]; integer round_const = 1 << (shift-1); for e = 0 to elements-1 bits(2*esize) element = Elem[operand, e, 2*esize]; integer res = (SInt(element) + round_const) >> shift; Elem[result, 2*e + 1, esize] = UnsignedSat(res, esize); Z[d] = result;


Internal version only: isa v33.11seprel, AdvSIMD v29.05, pseudocode v2021-09_rel, sve v2021-09_rc3d ; Build timestamp: 2021-10-06T11:41

Copyright © 2010-2021 Arm Limited or its affiliates. All rights reserved. This document is Non-Confidential.