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CPY (immediate, merging)

Copy signed integer immediate to vector elements (merging).

Copy a signed integer immediate to each active element in the destination vector. Inactive elements in the destination vector register remain unmodified.

The immediate operand is a signed value in the range -128 to +127, and for element widths of 16 bits or higher it may also be a signed multiple of 256 in the range -32768 to +32512 (excluding 0).

The immediate is encoded in 8 bits with an optional left shift by 8. The preferred disassembly when the shift option is specified is "#<simm8>, LSL #8". However an assembler and disassembler may also allow use of the shifted 16-bit value unless the immediate is 0 and the shift amount is 8, which must be unambiguously described as "#0, LSL #8".

This instruction is used by the aliases FMOV (zero, predicated), and MOV (immediate, predicated, merging).

313029282726252423222120191817161514131211109876543210
00000101size01Pg01shimm8Zd
M

CPY <Zd>.<T>, <Pg>/M, #<imm>{, <shift>}

if !HaveSVE() then UNDEFINED;
if size:sh == '001' then UNDEFINED;
integer esize = 8 << UInt(size);
integer g = UInt(Pg);
integer d = UInt(Zd);
boolean merging = TRUE;
integer imm = SInt(imm8);
if sh == '1' then imm = imm << 8;

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
<Pg>

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

<imm>

Is a signed immediate in the range -128 to 127, encoded in the "imm8" field.

<shift> Is the optional left shift to apply to the immediate, defaulting to LSL #0 and encoded in sh:
sh <shift>
0 LSL #0
1 LSL #8

Operation

CheckSVEEnabled();
integer elements = VL DIV esize;
bits(PL) mask = P[g];
bits(VL) dest = Z[d];
bits(VL) result;

for e = 0 to elements-1
    if ElemP[mask, e, esize] == '1' then
        Elem[result, e, esize] = imm<esize-1:0>;
    elsif merging then
        Elem[result, e, esize] = Elem[dest, e, esize];
    else
        Elem[result, e, esize] = Zeros();

Z[d] = result;

Operational information

If PSTATE.DIT is 1:

  • The execution time of this instruction is independent of:
    • The values of the data supplied in any of its operand registers when its governing predicate register contains the same value for each execution.
    • The values of the NZCV flags.
  • The response of this instruction to asynchronous exceptions does not vary based on:
    • The values of the data supplied in any of its operand registers when its governing predicate register contains the same value for each execution.
    • The values of the NZCV flags.

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 source 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.