Using Data Formats; Binary String; Unsigned - Analog Devices ADSP-BF53x Blackfin Reference

Using Data Formats

Using Data Formats
ADSP-BF53x/56x processors are primarily 16-bit, fixed-point machines.
Most operations assume a two's-complement number representation,
while others assume unsigned numbers or simple binary strings. Other
instructions support 32-bit integer arithmetic, with further special fea-
tures supporting 8-bit arithmetic and block floating point. For detailed
information about each number format, see
Formats."
In the ADSP-BF53x/56x processor family arithmetic, signed numbers are
always in two's-complement format. These processors do not use
signed-magnitude, one's-complement, binary-coded decimal (BCD), or
excess-n formats.

Binary String

The binary string format is the least complex binary notation; in it, 16 bits
are treated as a bit pattern. Examples of computations using this format
are the logical operations NOT, AND, OR, XOR. These ALU operations
treat their operands as binary strings with no provision for sign bit or
binary point placement.

Unsigned

Unsigned binary numbers may be thought of as positive and having nearly
twice the magnitude of a signed number of the same length. The processor
treats the least significant words of multiple precision numbers as
unsigned numbers.
2-4 ADSP-BF53x/BF56x Blackfin Processor Programming Reference
Appendix D, "Numeric