MADD
Multiply-add
This instruction multiplies two register values, adds a third register value, and writes
the result to the destination register.
If PSTATE.DIT is 1:
The execution time of this instruction is independent of:
The values of the data supplied in any of its registers.
The values of the NZCV flags.
The response of this instruction to asynchronous exceptions does not vary based on:
The values of the data supplied in any of its registers.
The values of the NZCV flags.
This instruction is used by the alias
MUL
Ra == '11111'
See
below for details of when the alias is preferred.
0
0
1
1
0
1
1
0
0
0
0
0
MADD <Wd>, <Wn>, <Wm>, <Wa>
1
MADD <Xd>, <Xn>, <Xm>, <Xa>
constant integer d = UInt(Rd);
constant integer n = UInt(Rn);
constant integer m = UInt(Rm);
constant integer a = UInt(Ra);
constant integer datasize = 32 << UInt(sf);
<Wd>
Is the 32-bit name of the general-purpose destination register, encoded in the "Rd" field.
<Wn>
Is the 32-bit name of the first general-purpose source register holding the multiplicand, encoded in the "Rn" field.
<Wm>
Is the 32-bit name of the second general-purpose source register holding the multiplier, encoded in the "Rm" field.
<Wa>
Is the 32-bit name of the third general-purpose source register holding the addend, encoded in the "Ra" field.
<Xd>
Is the 64-bit name of the general-purpose destination register, encoded in the "Rd" field.
<Xn>
Is the 64-bit name of the first general-purpose source register holding the multiplicand, encoded in the "Rn" field.
<Xm>
Is the 64-bit name of the second general-purpose source register holding the multiplier, encoded in the "Rm" field.
<Xa>
Is the 64-bit name of the third general-purpose source register holding the addend, encoded in the "Ra" field.
Alias Conditions
constant bits(datasize) operand1 = X[n, datasize];
constant bits(datasize) operand2 = X[m, datasize];
constant bits(datasize) operand3 = X[a, datasize];
constant integer result = UInt(operand3) + (UInt(operand1) * UInt(operand2));
X[d, datasize] = result<datasize-1:0>;