FMADD
Floating-point fused multiply-add (scalar)
This instruction multiplies the values of
the first two SIMD&FP source
registers, adds the product to the value of the third
SIMD&FP source register, and
writes the result to the SIMD&FP destination register.
A floating-point exception can be generated by this instruction.
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.
0
0
0
1
1
1
1
1
0
0
1
1
FMADD <Hd>, <Hn>, <Hm>, <Ha>
0
0
FMADD <Sd>, <Sn>, <Sm>, <Sa>
0
1
FMADD <Dd>, <Dn>, <Dm>, <Da>
if ftype == '10' || (ftype == '11' && !IsFeatureImplemented(FEAT_FP16)) then UNDEFINED;
constant integer d = UInt(Rd);
constant integer n = UInt(Rn);
constant integer m = UInt(Rm);
constant integer a = UInt(Ra);
constant integer esize = 8 << UInt(ftype EOR '10');
<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 holding the multiplicand, encoded in the "Rn" field.
<Hm>
Is the 16-bit name of the second SIMD&FP source register holding the multiplier, encoded in the "Rm" field.
<Ha>
Is the 16-bit name of the third SIMD&FP source register holding the addend, encoded in the "Ra" 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 holding the multiplicand, encoded in the "Rn" field.
<Sm>
Is the 32-bit name of the second SIMD&FP source register holding the multiplier, encoded in the "Rm" field.
<Sa>
Is the 32-bit name of the third SIMD&FP source register holding the addend, encoded in the "Ra" field.
<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 holding the multiplicand, encoded in the "Rn" field.
<Dm>
Is the 64-bit name of the second SIMD&FP source register holding the multiplier, encoded in the "Rm" field.
<Da>
Is the 64-bit name of the third SIMD&FP source register holding the addend, encoded in the "Ra" field.
CheckFPEnabled64();
constant bits(esize) addend = V[a, esize];
constant bits(esize) operand1 = V[n, esize];
constant bits(esize) operand2 = V[m, esize];
bits(128) result = if IsMerging(FPCR) then V[a, 128] else Zeros(128);
Elem[result, 0, esize] = FPMulAdd(addend, operand1, operand2, FPCR);
V[d, 128] = result;