MSUB Multiply-subtract This instruction multiplies two register values, subtracts the product from a third register value, and writes the result to the destination register. This instruction is a data-independent-time instruction as described in About PSTATE.DIT. This instruction is used by the alias MNEG Ra == '11111' See below for details of when the alias is preferred. 0 0 1 1 0 1 1 0 0 0 1 0 MSUB <Wd>, <Wn>, <Wm>, <Wa> 1 MSUB <Xd>, <Xn>, <Xm>, <Xa> 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 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 Conditions 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]; 2026-03-26 20:27:25 2026-03_rel