Analog Devices ADSP-BF53x Blackfin Reference page 713

"ASHIFT" Syntax
Both half-word registers in
prescribed in
shift_magnitude
The sign of the shift magnitude determines the direction of the shift for
the versions.
ASHIFT
• Positive shift magnitudes without the saturation flag ( – , S) pro-
duce Logical Left shifts.
• Positive shift magnitudes with the saturation flag ( – , S) produce
Arithmetic Left shifts.
• Negative shift magnitudes produce Arithmetic Right shifts.
In essence, the magnitude is the power of 2 multiplied by the
number. Positive magnitudes cause multiplication ( N x 2
ative magnitudes produce division ( N x 2
The
dest_reg
tion of the result is optional.
Valid shift magnitudes for 16-bit
included. If a number larger than these is supplied, the instruction masks
and ignores the more significant bits.
This instruction does not implicitly modify the
ally,
dest_reg
D-register for the
register.
Options
The instruction supports the ( – , S) option, which saturates the
ASHIFT
result.
ADSP-BF53x/BF56x Blackfin Processor Programming Reference
src_reg
, and the result stored into
and are both pairs of 16-bit half registers. Satura-
src_reg
can be the same D-register as
and the
dest_reg
Vector Operations
are shifted by the number of places
-n
or N / 2
are –16 through +15, zero
src_reg
src_reg
src_reg
explicitly modifies the source
src_reg
.
dest_reg
src_reg
n
), whereas neg-
n
).
values. Option-
. Using the same
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