Instruction Overview
14-8
ADSP-BF53x/BF56x Blackfin Processor Programming Reference
A0 = ASHIFT A0 BY
Dreg_lo
;
/* arithmetic right shift (b)*/
A1 = ASHIFT A1 BY
Dreg_lo
;
/* arithmetic right shift (b)*/
Syntax Terminology
Dreg
:
R7–0
Dreg_lo_hi
:
R7–0.L
,
R7–0.H
Dreg_lo
:
R7–0.L
uimm4
: 4-bit unsigned field, with a range of 0 through 15
uimm5
: 5-bit unsigned field, with a range of 0 through 31
opt_sat
: optional “(S)” (without the quotes) to invoke saturation of the
result. Not optional on versions that show “(S)” in the syntax.
Instruction Length
In the syntax, comment (a) identifies 16-bit instruction length. Comment
(b) identifies 32-bit instruction length.
Functional Description
The Arithmetic Shift instruction shifts a registered number a specified dis-
tance and direction while preserving the sign of the original number. The
sign bit value back-fills the left-most bit positions vacated by the arith-
metic right shift.
Specific versions of arithmetic left shift are supported, too. Arithmetic left
shift saturates the result if the value is shifted too far. A left shift that
would otherwise lose nonsign bits off the left-hand side saturates to the
maximum positive or negative value instead.
Содержание ADSP-BF53x Blackfin
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Страница 752: ...Examples 20 10 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 780: ...Product Identification Register 21 28 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 790: ...ADSP BF535 Flags A 10 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 800: ...Performance Monitor Registers B 10 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 994: ...Instructions Listed By Operation Code C 194 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 1042: ...Index I 40 ADSP BF53x BF56x Blackfin Processor Programming Reference...