Dual 16-bit Signed Multiply with Subtraction of products and 64-bit accumulation.
Syntax
SMLSD{X}{cond}
RdLo,
RdHi,
Rn,
Rm
where:
X
is an optional parameter. If X is
present, the most and least significant halfwords of the second
operand are exchanged before the multiplications occur.
cond
is an optional condition code.
RdLo, RdHi
are the destination registers for the 64-bit result.
They also hold the 64-bit accumulate operand. RdHi and RdLo must
be different registers.
Rn, Rm
are the registers holding the operands.
Operation
SMLSLD multiplies the bottom halfword of Rn with the bottom
halfword of Rm, and the top halfword of Rn with the
top halfword of Rm. It then subtracts the second product from the first,
adds the difference to the value in RdLo, RdHi, and
stores the result to RdLo, RdHi.
Register restrictions
You cannot use PC for any register.
You can use SP in ARM instructions but this is deprecated
in ARMv6T2 and above. You cannot use SP in Thumb instructions.
Condition flags
This instruction does not change the flags.
Architectures
This ARM instruction is available in ARMv6 and above.
This 32-bit Thumb instruction is available in ARMv6T2 and
above. For the ARMv7-M architecture, it is only available in an
ARMv7E-M implementation.
There is no 16-bit version of this instruction in Thumb.
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