Analog Devices ADSP-BF53x Blackfin Reference page 603

Example: If you use
clear
L2
beforehand can result in unexpected
The circular address buffer registers (Index, Length, and Base) are
not initialized automatically by Reset. Traditionally, user software
clears all the circular address buffer registers during boot-up to dis-
able circular buffering, then initializes them later, if needed.
To subtract immediate values from D-registers or P-registers, use a
negative constant in the Add Immediate instruction.
Flags Affected
None
Required Mode
User & Supervisor
Parallel Issue
This instruction can be issued in parallel with specific other instructions.
For details, see
Example
i0 -= 4 ;
i2 -= 2 ;
Also See
Add Immediate,
Special Applications
None
ADSP-BF53x/BF56x Blackfin Processor Programming Reference
to increment your address pointer, first
I2
to disable circular buffering. Failure to explicitly clear
"Issuing Parallel Instructions" on page
Subtract
Arithmetic Operations
values.
Ireg
20-1.
Lreg
15-91