ADSP-BF53x/BF56x Blackfin Processor Programming Reference
15-83
Arithmetic Operations
SIGNBITS
General Form
dest_reg = SIGNBITS sample_register
Syntax
Dreg_lo
= SIGNBITS
Dreg
;
/* 32-bit sample (b) */
Dreg_lo
= SIGNBITS
Dreg_lo_hi
;
/* 16-bit sample (b) */
Dreg_lo
= SIGNBITS A0 ;
/* 40-bit sample (b) */
Dreg_lo
= SIGNBITS A1 ;
/* 40-bit sample (b) */
Syntax Terminology
Dreg
:
R7–0
Dreg_lo
:
R7–0.L
Dreg_lo_hi
:
R7–0.L
,
R7–0.H
Instruction Length
In the syntax, comment (b) identifies 32-bit instruction length.
Functional Description
The Sign Bit instruction returns the number of sign bits in a number, and
can be used in conjunction with a shift to normalize numbers. This
instruction can operate on 16-bit, 32-bit, or 40-bit input numbers.
• For a 16-bit input, Sign Bit returns the number of leading sign bits
minus one, which is in the range 0 through 15. There are no spe-
cial cases. An input of all zeros r15 (all sign bits), and an
input of all ones also r15.
Содержание ADSP-BF53x Blackfin
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Страница 324: ...Instruction Overview 7 20 ADSP BF53x BF56x Blackfin Processor Programming Reference...
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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...