Analog Devices ADSP-BF53x Blackfin, Reference

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Glossary
1-16 ADSP-BF53x/BF56x Blackfin Processor Programming Reference
L
The ADSP-BF535 processor has fewer
ASTAT
flags and some flags
operate differently than subsequent Blackfin family products. For
more information on the ADSP-BF535 status flags, see
Table A-1
on page A-3 .
Fractional Convention
Fractional numbers include subinteger components less than ±1. Whereas
decimal fractions appear to the right of a decimal point, binary fractions
appear to the right of a binal point.
In DSP instructions that assume placement of a binal point, for example
in computing sign bits for normalization or for alignment purposes, the
binal point convention depends on the size of the register being used as
shown in
Table 1-4 and Figure 1-2 on page 1-17 .
L
This processor does not represent fractional values in 8-bit
registers.
Table 1-4. Fractional Conventions
Registers Size Format Notation
Si
gn
Bi
t
Ext
en
si
o
n
Bi
ts
F
ractional
Bi
ts
40-bit registers Signed Fractional 9.31 1 8 31
Unsigned Fractional 8.32 0 8 32
32-bit registers Signed Fractional 1.31 1 0 31
Unsigned Fractional 0.32 0 0 32
16-bit registers Signed Fractional 1.15 1 0 15
Unsigned Fractional 0.16 0 0 16