Multiply-add
This instruction multiplies two register values, adds a third register value, and writes the result to the destination register.
This instruction is used by the alias MUL.
| 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 |
| sf | 0 | 0 | 1 | 1 | 0 | 1 | 1 | 0 | 0 | 0 | Rm | 0 | Ra | Rn | Rd | ||||||||||||||||
| op54 | op31 | o0 | |||||||||||||||||||||||||||||
let d : integer{} = UInt(Rd); let n : integer{} = UInt(Rn); let m : integer{} = UInt(Rm); let a : integer{} = UInt(Ra); let datasize : integer{} = 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 | Is preferred when |
|---|---|
| MUL | Ra == '11111' |
let operand1 : bits(datasize) = X{}(n); let operand2 : bits(datasize) = X{}(m); let operand3 : bits(datasize) = X{}(a); let result : integer = UInt(operand3) + (UInt(operand1) * UInt(operand2)); X{datasize}(d) = result[datasize-1:0];
This instruction is a data-independent-time instruction as described in About PSTATE.DIT.
2026-03_rel 2026-03-26 20:48:11
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