SMSUBL
Signed multiply-subtract long
This instruction multiplies two 32-bit register values, subtracts
the product from a 64-bit register value, and writes the result to the 64-bit
destination register.
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.
This instruction is used by the alias
SMNEGL
Ra == '11111'
See
below for details of when the alias is preferred.
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SMSUBL <Xd>, <Wn>, <Wm>, <Xa>
constant integer d = UInt(Rd);
constant integer n = UInt(Rn);
constant integer m = UInt(Rm);
constant integer a = UInt(Ra);
<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 minuend, encoded in the "Ra" field.
Alias Conditions
constant bits(32) operand1 = X[n, 32];
constant bits(32) operand2 = X[m, 32];
constant bits(64) operand3 = X[a, 64];
constant integer result = SInt(operand3) - (SInt(operand1) * SInt(operand2));
X[d, 64] = result<63:0>;