You copied the Doc URL to your clipboard.

LSL (wide elements, predicated)

Logical shift left by 64-bit wide elements (predicated).

Shift left active elements of the first source vector by corresponding overlapping 64-bit elements of the second source vector and destructively place the results in the corresponding elements of the first source vector. The shift amount is a vector of unsigned 64-bit doubleword elements in which all bits are significant, and not used modulo the destination element size. Inactive elements in the destination vector register remain unmodified.

313029282726252423222120191817161514131211109876543210
00000100size011011100PgZmZdn
RLU

LSL <Zdn>.<T>, <Pg>/M, <Zdn>.<T>, <Zm>.D

if !HaveSVE() then UNDEFINED;
if size == '11' then UNDEFINED;
integer esize = 8 << UInt(size);
integer g = UInt(Pg);
integer dn = UInt(Zdn);
integer m = UInt(Zm);

Assembler Symbols

<Zdn>

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

<T> Is the size specifier, encoded in size:
size <T>
00 B
01 H
10 S
11 RESERVED
<Pg>

Is the name of the governing scalable predicate register P0-P7, encoded in the "Pg" field.

<Zm>

Is the name of the second source scalable vector register, encoded in the "Zm" field.

Operation

CheckSVEEnabled();
integer elements = VL DIV esize;
bits(PL) mask = P[g];
bits(VL) operand1 = Z[dn];
bits(VL) operand2 = Z[m];
bits(VL) result;

for e = 0 to elements-1
    bits(esize) element1 = Elem[operand1, e, esize];
    bits(64) element2 = Elem[operand2, (e * esize) DIV 64, 64];
    integer shift = Min(UInt(element2), esize);
    if ElemP[mask, e, esize] == '1' then
        Elem[result, e, esize] = LSL(element1, shift);
    else
        Elem[result, e, esize] = Elem[operand1, e, esize];

Z[dn] = result;

Operational information

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:

  • The MOVPRFX instruction must be unpredicated, or be predicated using the same governing predicate register and destination element size as this instruction.
  • The MOVPRFX instruction must specify the same destination register as this instruction.
  • The destination register must not refer to architectural register state referenced by any other source operand register of this instruction.