FMUL (scalar)

Floating-point Multiply (scalar). This instruction multiplies the floating-point values of the two source SIMD&FP registers, and writes the result 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.

313029282726252423222120191817161514131211109876543210
00011110ftype1Rm000010RnRd
op

Half-precision (ftype == 11)
(FEAT_FP16)

FMUL <Hd>, <Hn>, <Hm>

Single-precision (ftype == 00)

FMUL <Sd>, <Sn>, <Sm>

Double-precision (ftype == 01)

FMUL <Dd>, <Dn>, <Dm>

integer d = UInt(Rd); integer n = UInt(Rn); integer m = UInt(Rm); integer esize; case ftype of when '00' esize = 32; when '01' esize = 64; when '10' UNDEFINED; when '11' if HaveFP16Ext() then esize = 16; else UNDEFINED; boolean negated = (op == '1');

Assembler Symbols

<Dd>

Is the 64-bit name of the SIMD&FP destination register, encoded in the "Rd" field.

<Dn>

Is the 64-bit name of the first SIMD&FP source register, encoded in the "Rn" field.

<Dm>

Is the 64-bit name of the second SIMD&FP source register, encoded in the "Rm" field.

<Hd>

Is the 16-bit name of the SIMD&FP destination register, encoded in the "Rd" field.

<Hn>

Is the 16-bit name of the first SIMD&FP source register, encoded in the "Rn" field.

<Hm>

Is the 16-bit name of the second SIMD&FP source register, encoded in the "Rm" field.

<Sd>

Is the 32-bit name of the SIMD&FP destination register, encoded in the "Rd" field.

<Sn>

Is the 32-bit name of the first SIMD&FP source register, encoded in the "Rn" field.

<Sm>

Is the 32-bit name of the second SIMD&FP source register, encoded in the "Rm" field.

Operation

CheckFPEnabled64(); bits(esize) operand1 = V[n]; bits(esize) operand2 = V[m]; FPCRType fpcr = FPCR[]; boolean merge = IsMerging(fpcr); bits(128) result = if merge then V[n] else Zeros(); bits(esize) product = FPMul(operand1, operand2, fpcr); if negated then product = FPNeg(product); Elem[result, 0, esize] = product; V[d] = result;


Internal version only: isa v33.11seprel, AdvSIMD v29.05, pseudocode v2021-09_rel, sve v2021-09_rc3d ; Build timestamp: 2021-10-06T11:41

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