MLS Multiply and Subtract Multiply and Subtract multiplies two register values, and subtracts the product from a third register value. The least significant 32 bits of the result are written to the destination register. These 32 bits do not depend on whether the source register values are considered to be signed values or unsigned values. For more information about the CONSTRAINED UNPREDICTABLE behavior of this instruction, see Architectural Constraints on UNPREDICTABLE behaviors. This instruction is a data-independent-time instruction as described in About the DIT bit. It has encodings from the following instruction sets: A32 ( A1 ) and T32 ( T1 ) . != 1111 0 0 0 0 0 1 1 0 1 0 0 1 MLS{<c>}{<q>} <Rd>, <Rn>, <Rm>, <Ra> let d : integer = UInt(Rd); let n : integer = UInt(Rn); let m : integer = UInt(Rm); let a : integer = UInt(Ra); if d == 15 || n == 15 || m == 15 || a == 15 then UnpredictableProcedure(); end; 1 1 1 1 1 0 1 1 0 0 0 0 0 0 0 1 MLS{<c>}{<q>} <Rd>, <Rn>, <Rm>, <Ra> let d : integer = UInt(Rd); let n : integer = UInt(Rn); let m : integer = UInt(Rm); let a : integer = UInt(Ra); if d == 15 || n == 15 || m == 15 || a == 15 then UnpredictableProcedure(); end; // Armv8-A removes UNPREDICTABLE for R13 <c> See Standard assembler syntax fields. <q> See Standard assembler syntax fields. <Rd> Is the general-purpose destination register, encoded in the "Rd" field. <Rn> Is the first general-purpose source register holding the multiplicand, encoded in the "Rn" field. <Rm> Is the second general-purpose source register holding the multiplier, encoded in the "Rm" field. <Ra> Is the third general-purpose source register holding the minuend, encoded in the "Ra" field. if ConditionPassed() then EncodingSpecificOperations(); let operand1 : integer = SInt(R(n)); // operand1 = UInt(R[n]) produces the same final results let operand2 : integer = SInt(R(m)); // operand2 = UInt(R[m]) produces the same final results let addend : integer = SInt(R(a)); // addend = UInt(R[a]) produces the same final results let result : integer = addend - operand1 * operand2; R(d) = result[31:0]; end; 2026-03-26 20:27:25 2026-03_rel