Multiply-Subtract multiplies two register values, subtracts the product from a third register value, and writes the result to the destination register.
This instruction is used by the alias MNEG.
| 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 | 1 | Ra | Rn | Rd | ||||||||||||||||
| o0 | |||||||||||||||||||||||||||||||
integer d = UInt(Rd); integer n = UInt(Rn); integer m = UInt(Rm); integer a = UInt(Ra); integer destsize = if sf == '1' then 64 else 32; integer datasize = destsize; boolean sub_op = (o0 == '1');
| <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 minuend, 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 minuend, encoded in the "Ra" field. |
| Alias | Is preferred when |
|---|---|
| MNEG | Ra == '11111' |
bits(datasize) operand1 = X[n]; bits(datasize) operand2 = X[m]; bits(destsize) operand3 = X[a]; integer result; if sub_op then result = UInt(operand3) - (UInt(operand1) * UInt(operand2)); else result = UInt(operand3) + (UInt(operand1) * UInt(operand2)); X[d] = result<destsize-1:0>;
If PSTATE.DIT is 1:
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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