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## MLS

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.

It has encodings from the following instruction sets: A32 ( A1 ) and T32 ( T1 ) .

### A1

 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 != 1111 0 0 0 0 0 1 1 0 Rd Ra Rm 1 0 0 1 Rn cond

#### A1

MLS{<c>}{<q>} <Rd>, <Rn>, <Rm>, <Ra>

```d = UInt(Rd);  n = UInt(Rn);  m = UInt(Rm);  a = UInt(Ra);
if d == 15 || n == 15 || m == 15 || a == 15 then UNPREDICTABLE;```

### T1

 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 1 1 1 1 1 0 1 1 0 0 0 0 Rn Ra Rd 0 0 0 1 Rm

#### T1

MLS{<c>}{<q>} <Rd>, <Rn>, <Rm>, <Ra>

```d = UInt(Rd);  n = UInt(Rn);  m = UInt(Rm);  a = UInt(Ra);
if d == 15 || n == 15 || m == 15 || a == 15 then UNPREDICTABLE;
// Armv8-A removes UNPREDICTABLE for R13```

For more information about the constrained unpredictable behavior of this instruction, see Architectural Constraints on UNPREDICTABLE behaviors.

### Assembler Symbols



 Is the general-purpose destination register, encoded in the "Rd" field.
 Is the first general-purpose source register holding the multiplicand, encoded in the "Rn" field.
 Is the second general-purpose source register holding the multiplier, encoded in the "Rm" field.
 Is the third general-purpose source register holding the minuend, encoded in the "Ra" field.

### Operation

```if ConditionPassed() then
EncodingSpecificOperations();
operand1 = SInt(R[n]);  // operand1 = UInt(R[n]) produces the same final results
operand2 = SInt(R[m]);  // operand2 = UInt(R[m]) produces the same final results
addend   = SInt(R[a]);  // addend   = UInt(R[a]) produces the same final results
result = addend - operand1 * operand2;
R[d] = result<31:0>;```

### Operational information

If CPSR.DIT is 1, this instruction has passed its condition execution check, and does not use R15 as either its source or destination:

• The execution time of this instruction is independent of:
• The values of the data supplied in any of its registers.
• The values of the NZCV flags.
• The response of this instruction to asynchronous exceptions does not vary based on:
• The values of the data supplied in any of its registers.
• The values of the NZCV flags.