Analog Devices ADSP-BF53x Blackfin Reference page 566

Instruction Overview
Instruction Length
In the syntax, comment (b) identifies 32-bit instruction length.
Functional Description
The Multiply and Multiply-Accumulate to Accumulator instruction mul-
tiplies two 16-bit half-word operands. It stores, adds or subtracts the
product into a designated Accumulator with saturation.
The Multiply-and-Accumulate Unit 0 (MAC0) portion of the architecture
performs operations that involve Accumulator
operations.
By default, the instruction treats both operands of both MACs as signed
fractions with left-shift correction as required.
Options
The Multiply and Multiply-Accumulate to Accumulator instruction sup-
ports the following options. Saturation is supported for every option.
When the
(M)
their Accumulator products at 32 bits. MAC1 multiplies signed fractions
by unsigned fractions and MAC0 multiplies signed fractions.
When used together, the order of the options in the syntax makes no
difference.
In fractional mode, the product of the most negative representable frac-
tion times itself (for example, 0x8000 times 0x8000) is saturated to the
maximum representable positive fraction (0x7FFF) before accumulation.
See "Saturation" on page 1-17
15-54 ADSP-BF53x/BF56x Blackfin Processor Programming Reference
and options are used together, both MACs saturate
(W32)
for a description of saturation behavior.
. MAC1 performs
A0 A1