USRA

Unsigned shift right and accumulate (immediate)

Shift right by immediate each unsigned element of the source vector, inserting zeroes, and add the truncated intermediate result destructively to the corresponding elements of the addend vector. The immediate shift amount is an unsigned value in the range 1 to number of bits per element. This instruction is unpredicated.

313029282726252423222120191817161514131211109876543210
01000101tszh0tszlimm3111001ZnZda
RU

USRA <Zda>.<T>, <Zn>.<T>, #<const>

if !IsFeatureImplemented(FEAT_SVE2) && !IsFeatureImplemented(FEAT_SME) then UNDEFINED; constant bits(4) tsize = tszh:tszl; if tsize == '0000' then UNDEFINED; constant integer esize = 8 << HighestSetBit(tsize); constant integer n = UInt(Zn); constant integer da = UInt(Zda); constant integer shift = (2 * esize) - UInt(tsize:imm3);

Assembler Symbols

<Zda>

Is the name of the third source and destination scalable vector register, encoded in the "Zda" field.

<T>

Is the size specifier, encoded in tszh:tszl:

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

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

<const>

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

Operation

CheckSVEEnabled(); constant integer VL = CurrentVL; constant integer elements = VL DIV esize; constant bits(VL) operand1 = Z[n, VL]; constant bits(VL) operand2 = Z[da, VL]; bits(VL) result; for e = 0 to elements-1 constant integer element = UInt(Elem[operand1, e, esize]) >> shift; Elem[result, e, esize] = Elem[operand2, e, esize] + element<esize-1:0>; Z[da, VL] = result;

Operational information

If FEAT_SVE2 is implemented or FEAT_SME is implemented, then if PSTATE.DIT is 1:

This instruction might be immediately preceded in program order by a MOVPRFX instruction. The MOVPRFX must conform to all of the following requirements, otherwise the behavior of the MOVPRFX and this instruction is constrained unpredictable:


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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