UMADDL

Unsigned multiply-add long

This instruction multiplies two 32-bit register values, adds a 64-bit register value, and writes the result to the 64-bit destination register.

Encoding: 64-bit

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
1	0	0	1	1	0	1	1	1	0	1						0
sf	op54							U			Rm					o0	Ra					Rn					Rd

UMADDL <Xd>, <Wn>, <Wm>, <Xa>

Decoding algorithm

constant integer d = UInt(Rd);
constant integer n = UInt(Rn);
constant integer m = UInt(Rm);
constant integer a = UInt(Ra);

Operation

constant bits(32) operand1 = X[n, 32];
constant bits(32) operand2 = X[m, 32];
constant bits(64) operand3 = X[a, 64];

constant integer result = UInt(operand3) + (UInt(operand1) * UInt(operand2));

X[d, 64] = result<63:0>;

Explanations

<Xd>: Is the 64-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.
<Xa>: Is the 64-bit name of the third general-purpose source register holding the addend, encoded in the "Ra" field.

Operational Notes

If PSTATE.DIT is 1:

• 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.