FMOV (vector, immediate)

Floating-point move immediate (vector). This instruction copies an immediate floating-point constant into every element of the SIMD&FP destination register.

Depending on the settings in the CPACR_EL1, CPTR_EL2, and CPTR_EL3 registers, and the current Security state and Exception level, an attempt to execute the instruction might be trapped.

It has encodings from 2 classes: Half-precision and Single-precision and double-precision

Half-precision
(FEAT_FP16)

313029282726252423222120191817161514131211109876543210
0Q00111100000abc111111defghRd
opcmodeo2

FMOV <Vd>.<T>, #<imm>

if !IsFeatureImplemented(FEAT_FP16) then UNDEFINED; integer rd = UInt(Rd); constant integer datasize = 64 << UInt(Q); bits(datasize) imm; bits(8) imm8 = a:b:c:d:e:f:g:h; bits(16) imm16 = imm8<7>:NOT(imm8<6>):Replicate(imm8<6>, 2):imm8<5:0>:Zeros(6); imm = Replicate(imm16, datasize DIV 16);

Single-precision and double-precision

313029282726252423222120191817161514131211109876543210
0Qop0111100000abc111101defghRd
cmodeo2

Single-precision (op == 0)

FMOV <Vd>.<T>, #<imm>

Double-precision (Q == 1 && op == 1)

FMOV <Vd>.2D, #<imm>

integer rd = UInt(Rd); constant integer datasize = 64 << UInt(Q); bits(datasize) imm; bits(64) imm64; if cmode:op == '11111' then // FMOV Dn,#imm is in main FP instruction set if Q == '0' then UNDEFINED; imm64 = AdvSIMDExpandImm(op, cmode, a:b:c:d:e:f:g:h); imm = Replicate(imm64, datasize DIV 64);

Assembler Symbols

<Vd>

Is the name of the SIMD&FP destination register, encoded in the "Rd" field.

<T>

For the half-precision variant: is an arrangement specifier, encoded in Q:

Q <T>
0 4H
1 8H

For the single-precision variant: is an arrangement specifier, encoded in Q:

Q <T>
0 2S
1 4S
<imm>

Is a signed floating-point constant with 3-bit exponent and normalized 4 bits of precision, encoded in "a:b:c:d:e:f:g:h". For details of the range of constants available and the encoding of <imm>, see Modified immediate constants in A64 floating-point instructions.

Operation

CheckFPAdvSIMDEnabled64(); V[rd, datasize] = imm;


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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