ARM Architecture Reference Manual ARMv7-A and ARMv7-R edition

A4.4.3 Multiply instructions
The Instruction Sets
These instructions can operate on signed or unsigned quantities. In some types of operation, the results are
same whether the operands are signed or unsigned.
Table A4-4 summarizes the multiply instructions where there is no distinction between signed and
unsigned quantities.
The least significant 32 bits of the result are used. More significant bits are discarded.
Table A4-5 summarizes the signed multiply instructions.
Table A4-6 on page A4-12 summarizes the unsigned multiply instructions.
Table A4-4 General multiply instructions
Instruction See Operation (number of bits)
Multiply Accumulate MLA on page A8-190 32 = 32 + 32 x 32
Multiply and Subtract MLS on page A8-192 32 = 32 – 32 x 32
Multiply MUL on page A8-212 32 = 32 x 32
Table A4-5 Signed multiply instructions
Instruction See Operation (number of bits)
Signed Multiply Accumulate (halfwords) SMLABB, SMLABT,
SMLATB, SMLATT on
page A8-330
32 = 32 + 16 x 16
Signed Multiply Accumulate Dual SMLAD on page A8-332 32 = 32 + 16 x 16 + 16 x 16
Signed Multiply Accumulate Long SMLAL on page A8-334 64 = 64 + 32 x 32
Signed Multiply Accumulate Long (halfwords) SMLALBB, SMLALBT,
SMLALTB, SMLALTT on
page A8-336
64 = 64 + 16 x 16
Signed Multiply Accumulate Long Dual SMLALD on page A8-338 64 = 64 + 16 x 16 + 16 x 16
Signed Multiply Accumulate (word by
halfword)
SMLAWB, SMLAWT on
page A8-340
32 = 32 + 32 x 16 a
Signed Multiply Subtract Dual SMLSD on page A8-342 32 = 32 + 16 x 16 – 16 x 16
Signed Multiply Subtract Long Dual SMLSLD on page A8-344 64 = 64 + 16 x 16 – 16 x 16
Signed Most Significant Word Multiply
Accumulate
SMMLA on page A8-346 32 = 32 + 32 x 32 b
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