Instruction Overview
15-54
ADSP-BF53x/BF56x Blackfin Processor Programming Reference
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
A0
. MAC1 performs
A1
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)
and
(W32)
options are used together, both MACs saturate
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
for a description of saturation behavior.
Summary of Contents for ADSP-BF53x Blackfin
Page 38: ...Conventions xxxviii ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 134: ...System Reset and Powerup 3 18 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 324: ...Instruction Overview 7 20 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 486: ...Instruction Overview 13 28 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 512: ...Instruction Overview 14 26 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 604: ...Instruction Overview 15 92 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 688: ...Instruction Overview 18 48 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 742: ...Instruction Overview 19 54 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 752: ...Examples 20 10 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 790: ...ADSP BF535 Flags A 10 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 800: ...Performance Monitor Registers B 10 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Page 1042: ...Index I 40 ADSP BF53x BF56x Blackfin Processor Programming Reference...