MLA, MLAS Multiply Accumulate Multiply Accumulate multiplies two register values, and adds 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. In an A32 instruction, the condition flags can optionally be updated based on the result. Use of this option adversely affects performance on many implementations. 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 0 1 1 0 0 1 1 MLAS{<c>}{<q>} <Rd>, <Rn>, <Rm>, <Ra> 0 MLA{<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); let setflags : boolean = (S == '1'); if d == 15 || n == 15 || m == 15 || a == 15 then UnpredictableProcedure(); end; 1 1 1 1 1 0 1 1 0 0 0 0 != 1111 0 0 0 0 MLA{<c>}{<q>} <Rd>, <Rn>, <Rm>, <Ra> if Ra == '1111' then See("MUL"); end; let d : integer = UInt(Rd); let n : integer = UInt(Rn); let m : integer = UInt(Rm); let a : integer = UInt(Ra); let setflags : boolean = FALSE; // Armv8-A removes UNPREDICTABLE for R13 if d == 15 || n == 15 || m == 15 then UnpredictableProcedure(); end; <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 addend, 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 = operand1 * operand2 + addend; R(d) = result[31:0]; if setflags then PSTATE.N = result[31]; PSTATE.Z = IsZeroBit{32}(result[31:0]); // PSTATE.C, PSTATE.V unchanged end; end; 2026-03-12 12:23:09 2025-09_rel_asl1