Analog Devices ADSP-BF53x Blackfin Reference page 599

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
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
values.
• saturate the result
(S)
• no saturation
(NS)
See "Saturation" on page 1-17
The Subtract instruction has no subtraction equivalent of the addition
syntax for P-registers.
Flags Affected
This instruction affects flags as follows.
• is set if result is zero; cleared if nonzero.
AZ
• is set if result is negative; cleared if non-negative.
AN
• is set if the operation generates a carry; cleared if no carry.
AC0
• is set if result overflows; cleared if no overflow.
V
ADSP-BF53x/BF56x Blackfin Processor Programming Reference
15-5.
appears, substitute one of the following
sat_flag
for a description of saturation behavior.
Arithmetic Operations
15-87