ADSP-BF53x/BF56x Blackfin Processor Programming Reference
2-49
Computational Units
The arithmetic shift and logical shift operations can be further broken
into subsections. Instructions that are intended to operate on 16-bit single
or paired numeric values (as would occur in many DSP algorithms) can
use the instructions
ASHIFT
and
LSHIFT
. These are typically three-operand
instructions.
Instructions that are intended to operate on a 32-bit register value and use
two operands, such as instructions frequently used by a compiler, can use
the
>>>
and
>>
instructions.
Arithmetic shift, logical shift, and rotate instructions can obtain the shift
argument from a register or directly from an immediate value in the
instruction. For details about shifter related instructions, see
“Shifter
Instruction Summary” on page 2-53
.
Two-Operand Shifts
Two-operand shift instructions shift an input register and deposit the
result in the same register.
Immediate Shifts
An immediate shift instruction shifts the input bit pattern to the right
(downshift) or left (upshift) by a given number of bits. Immediate shift
instructions use the data value in the instruction itself to control the
amount and direction of the shifting operation.
The following example shows the input value downshifted.
R0 contains 0000 B6A3 ;
R0 >>= 0x04 ;
results in
R0 contains 0000 0B6A ;
Содержание ADSP-BF53x Blackfin
Страница 38: ...Conventions xxxviii ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 134: ...System Reset and Powerup 3 18 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 324: ...Instruction Overview 7 20 ADSP BF53x BF56x Blackfin Processor Programming Reference...
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Страница 742: ...Instruction Overview 19 54 ADSP BF53x BF56x Blackfin Processor Programming Reference...
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...