Analog Devices ADSP-BF53x Blackfin Reference page 495

The " " versions of this instruction support two modes.
ASHIFT
1. Default–arithmetic right shifts and logical left shifts.
shifts do not guarantee sign bit preservation. The "
automatically select arithmetic and logical shift modes based on the
sign of the
2. Saturation mode–arithmetic right and left shifts that saturate if the
value is shifted left too far.
The " " and "
>>>=
right shifts. If left shifts are desired, the programmer must explicitly use
arithmetic " " (saturating) or logical "
<<
Logical left shift instructions are duplicated in the Syntax section
for programmer convenience. See the Logical Shift instruction for
details on those operations.
The Arithmetic Shift instruction supports 16-bit and 32-bit instruction
length.
• The "
>>>=
smaller code at the expense of flexibility.
• The "
>>>
length, providing a separate source and destination register, alter-
native data sizes, and parallel issue with Load/Store instructions.
Both syntaxes support constant and registered shift magnitudes.
For the
ASHIFT
direction of the shift.
• Positive shift magnitudes produce Logical Left shifts.
• Negative shift magnitudes produce Arithmetic Right shifts.
ADSP-BF53x/BF56x Blackfin Processor Programming Reference
shift_magnitude
" versions of this instruction supports only arithmetic
>>>
" syntax instruction is 16 bits in length, allowing for
", " ", and "
<< ASHIFT
versions, the sign of the shift magnitude determines the
Shift/Rotate Operations
.
" (non-saturating) instructions.
<<
" syntax instructions are 32 bits in
left
Logical
" versions
ASHIFT
14-9