ADSP-BF53x/BF56x Blackfin Processor Programming Reference
15-87
Arithmetic Operations
There are two ways to specify subtraction on 32-bit data. One instruction
that is 16-bit instruction length does not support saturation. The other
instruction, which is 32-bit instruction length, optionally supports satura-
tion. The larger DSP instruction can sometimes save execution time
because it can be issued in parallel with certain other instructions. See
“Parallel Issue” on page 15-5
.
The instructions for 16-bit data use half-word data register operands and
store the result in a half-word data register.
All the instructions for 16-bit data are 32-bit instruction length.
In the syntax, where
sat_flag
appears, substitute one of the following
values.
•
(S)
saturate the result
•
(NS)
no saturation
See
“Saturation” on page 1-17
for a description of saturation behavior.
The Subtract instruction has no subtraction equivalent of the addition
syntax for P-registers.
Flags Affected
This instruction affects flags as follows.
•
AZ
is set if result is zero; cleared if nonzero.
•
AN
is set if result is negative; cleared if non-negative.
•
AC0
is set if the operation generates a carry; cleared if no carry.
•
V
is set if result overflows; cleared if no overflow.
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...
Страница 486: ...Instruction Overview 13 28 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 512: ...Instruction Overview 14 26 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 604: ...Instruction Overview 15 92 ADSP BF53x BF56x Blackfin Processor Programming Reference...
Страница 688: ...Instruction Overview 18 48 ADSP BF53x BF56x Blackfin Processor Programming Reference...
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...