FMUL (by element)

Floating-point Multiply (by element). This instruction multiplies the vector elements in the first source SIMD&FP register by the specified value in the second source SIMD&FP register, places the results in a vector, and writes the vector to the destination SIMD&FP register. All the values in this instruction are floating-point values.

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 4 classes: Scalar, half-precision , Scalar, single-precision and double-precision , Vector, half-precision and Vector, single-precision and double-precision

Scalar, half-precision
(FEAT_FP16)

if !IsFeatureImplemented(FEAT_FP16) then UNDEFINED; constant integer idxdsize = 64 << UInt(H); integer n = UInt(Rn); integer m = UInt(Rm); integer d = UInt(Rd); integer index = UInt(H:L:M); constant integer esize = 16; constant integer datasize = esize; integer elements = 1; boolean mulx_op = (U == '1');

Scalar, single-precision and double-precision

constant integer idxdsize = 64 << UInt(H); integer index; bit Rmhi = M; case sz:L of when '0x' index = UInt(H:L); when '10' index = UInt(H); when '11' UNDEFINED; integer d = UInt(Rd); integer n = UInt(Rn); integer m = UInt(Rmhi:Rm); constant integer esize = 32 << UInt(sz); constant integer datasize = esize; integer elements = 1; boolean mulx_op = (U == '1');

Vector, half-precision
(FEAT_FP16)

if !IsFeatureImplemented(FEAT_FP16) then UNDEFINED; constant integer idxdsize = 64 << UInt(H); integer n = UInt(Rn); integer m = UInt(Rm); integer d = UInt(Rd); integer index = UInt(H:L:M); constant integer esize = 16; constant integer datasize = 64 << UInt(Q); integer elements = datasize DIV esize; boolean mulx_op = (U == '1');

Vector, single-precision and double-precision

constant integer idxdsize = 64 << UInt(H); integer index; bit Rmhi = M; case sz:L of when '0x' index = UInt(H:L); when '10' index = UInt(H); when '11' UNDEFINED; integer d = UInt(Rd); integer n = UInt(Rn); integer m = UInt(Rmhi:Rm); if sz:Q == '10' then UNDEFINED; constant integer esize = 32 << UInt(sz); constant integer datasize = 64 << UInt(Q); integer elements = datasize DIV esize; boolean mulx_op = (U == '1');