Base Instructions | SIMD&FP Instructions | SVE Instructions | SME Instructions | Index by Encoding | Shared Pseudocode | Proprietary Notice

## FMUL (vector)

Floating-point Multiply (vector). This instruction multiplies corresponding floating-point values in the vectors in the two source SIMD&FP registers, places the result in a vector, and writes the vector to the destination SIMD&FP register.

This instruction can generate a floating-point exception. Depending on the settings in FPCR, the exception results in either a flag being set in FPSR, or a synchronous exception being generated. For more information, see Floating-point exception traps.

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)

31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
0 | Q | 1 | 0 | 1 | 1 | 1 | 0 | 0 | 1 | 0 | Rm | 0 | 0 | 0 | 1 | 1 | 1 | Rn | Rd
|  | U |  | a |  |  |  | opcode |  |  |

####

FMUL <Vd>.<T>, <Vn>.<T>, <Vm>.<T>

if !IsFeatureImplemented(FEAT_FP16) then UNDEFINED; integer d = UInt(Rd); integer n = UInt(Rn); integer m = UInt(Rm); constant integer esize = 16; constant integer datasize = 64 << UInt(Q); integer elements = datasize DIV esize;

### Single-precision and double-precision

31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0
0 | Q | 1 | 0 | 1 | 1 | 1 | 0 | 0 | sz | 1 | Rm | 1 | 1 | 0 | 1 | 1 | 1 | Rn | Rd
|  | U |  |  |  |  | opcode |  |  |

####

FMUL <Vd>.<T>, <Vn>.<T>, <Vm>.<T>

integer d = UInt(Rd); integer n = UInt(Rn); integer m = UInt(Rm); if sz:Q == '10' then UNDEFINED; constant integer esize = 32 << UInt(sz); constant integer datasize = 64 << UInt(Q); integer elements = datasize DIV esize;

### 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 and double-precision variant: is an arrangement specifier, encoded in sz:Q:
sz | Q | <T>
--- | --- | ---
0 | 0 | 2S
0 | 1 | 4S
1 | 0 | RESERVED
1 | 1 | 2D

<Vn> | Is the name of the first SIMD&FP source register, encoded in the "Rn" field.

<Vm> | Is the name of the second SIMD&FP source register, encoded in the "Rm" field.

### Operation

CheckFPAdvSIMDEnabled64(); bits(datasize) operand1 = V[n, datasize]; bits(datasize) operand2 = V[m, datasize]; bits(datasize) result; bits(esize) element1; bits(esize) element2; for e = 0 to elements-1 element1 = Elem[operand1, e, esize]; element2 = Elem[operand2, e, esize]; Elem[result, e, esize] = FPMul(element1, element2, FPCR); V[d, datasize] = result;

Base Instructions | SIMD&FP Instructions | SVE Instructions | SME Instructions | Index by Encoding | Shared Pseudocode | Proprietary Notice

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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