Analog Devices ADSP-BF53x Blackfin Reference page 72

Data Types
Some instructions manipulate data in the registers by sign-extending or
zero-extending the data to 32 bits:
• Instructions zero-extend unsigned data
• Instructions sign-extend signed 16-bit half words and 8-bit bytes
Other instructions manipulate data as 32-bit numbers. In addition, two
16-bit half words or four 8-bit bytes can be manipulated as 32-bit values.
In Table 2-2, note the meaning of these symbols:
• s = sign bit(s)
• d = data bit(s)
• "." = decimal point by convention; however, a decimal point does
not literally appear in the number.
• Italics denotes data from a source other than adjacent bits.
2-12 ADSP-BF53x/BF56x Blackfin Processor Programming Reference