INDEX (immediates)

Create index starting from and incremented by immediate

This instruction populates the destination vector by setting the first element to the first signed immediate integer operand and monotonically incrementing the value by the second signed immediate integer operand for each subsequent element. This instruction is unpredicated.

SVE
(FEAT_SVE || FEAT_SME)

313029282726252423222120191817161514131211109876543210
00000100size1imm5b010000imm5Zd

Encoding

INDEX <Zd>.<T>, #<imm1>, #<imm2>

Decode for this encoding

if !IsFeatureImplemented(FEAT_SVE) && !IsFeatureImplemented(FEAT_SME) then EndOfDecode(Decode_UNDEF); end; let esize : integer{} = 8 << UInt(size); let d : integer = UInt(Zd); let imm1 : integer = SInt(imm5); let imm2 : integer = SInt(imm5b);

Assembler Symbols

<Zd>

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

<T>

Is the size specifier, encoded in size:

size <T>
00 B
01 H
10 S
11 D
<imm1>

Is the first signed immediate operand, in the range -16 to 15, encoded in the "imm5" field.

<imm2>

Is the second signed immediate operand, in the range -16 to 15, encoded in the "imm5b" field.

Operation

CheckSVEEnabled(); let VL : integer{} = CurrentVL(); let elements : integer = VL DIV esize; var result : bits(VL); for e = 0 to elements-1 do let index : integer = imm1 + e * imm2; result[e*:esize] = index[esize-1:0]; end; Z{VL}(d) = result;


2026-03_rel 2026-03-26 20:48:11

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