ASRD

Arithmetic shift right for divide by immediate (predicated)

Shift right by immediate, preserving the sign bit, each active element of the source vector, and destructively place the results in the corresponding elements of the source vector. The result rounds toward zero as in a signed division. The immediate shift amount is an unsigned value in the range 1 to number of bits per element. Inactive elements in the destination vector register remain unmodified.

313029282726252423222120191817161514131211109876543210
00000100tszh000100100Pgtszlimm3Zdn
LU

ASRD <Zdn>.<T>, <Pg>/M, <Zdn>.<T>, #<const>

if !HaveSVE() && !HaveSME() then UNDEFINED; bits(4) tsize = tszh:tszl; if tsize == '0000' then UNDEFINED; constant integer esize = 8 << HighestSetBit(tsize); integer g = UInt(Pg); integer dn = UInt(Zdn); integer shift = (2 * esize) - UInt(tsize:imm3);

Assembler Symbols

<Zdn>

Is the name of the source and destination scalable vector register, encoded in the "Zdn" 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
<Pg>

Is the name of the governing scalable predicate register P0-P7, encoded in the "Pg" 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 PL = VL DIV 8; constant integer elements = VL DIV esize; bits(PL) mask = P[g, PL]; bits(VL) operand1 = Z[dn, VL]; bits(VL) result; for e = 0 to elements-1 if ActivePredicateElement(mask, e, esize) then integer element1 = SInt(Elem[operand1, e, esize]); if element1 < 0 then element1 = element1 + ((1 << shift) - 1); Elem[result, e, esize] = (element1 >> shift)<esize-1:0>; else Elem[result, e, esize] = Elem[operand1, e, esize]; Z[dn, 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 instruction must conform to all of the following requirements, otherwise the behavior of the MOVPRFX and this instruction is unpredictable:


Internal version only: aarchmrs v2023-12_rel, pseudocode v2023-12_rel, sve v2023-12_rel ; Build timestamp: 2023-12-15T16:46

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