Modify - Decrement - Analog Devices ADSP-BF53x Blackfin Reference

Instruction Overview
Modify – Decrement
General Form
dest_reg -= src_reg
Syntax
40-Bit Accumulators
A0 -= A1 ;
the result at 40 bits (b) */
A0 -= A1 (W32) ;
rement and saturate the result at 32 bits, sign extended (b) */
32-Bit Registers
Preg -= Preg ;
Ireg -= Mreg ;
Syntax Terminology
: , ,
Preg P5–0 SP
:
Ireg I3–0
:
Mreg M3–0
Instruction Length
In the syntax, comment (a) identifies 16-bit instruction length. Comment
(b) identifies 32-bit instruction length.
Functional Description
The Modify – Decrement instruction decrements a register by a
user-defined quantity.
15-34 ADSP-BF53x/BF56x Blackfin Processor Programming Reference
/* dest_reg_new = dest_reg_old - src_reg, saturate
/* dest_reg_new = dest_reg_old - src_reg, dec-
/* dest_reg_new = dest_reg_old - src_reg (a) */
/* dest_reg_new = dest_reg_old - src_reg (a) */
FP