User`s guide

C for DSP56800E
Calling Conventions and Stack Frames
117Targeting MC56F83xx/DSP5685x Controllers
Arithmetic Logic Unit
(ALU) (continued)
A10 32 Volatile (non-SOC)
A 36 Volatile (non-SOC)
B2 4 Volatile (non-SOC)
B1 16 Volatile (non-SOC)
B0 16 Volatile (non-SOC)
B10 32 Volatile (non-SOC)
B 36 Volatile (non-SOC)
C2 4 Volatile (non-SOC)
C1 16 Non-Volatile (SOC)
C0 16 Non-Volatile (SOC)
C10 32 Non-Volatile (SOC)
C 36 Volatile (non-SOC) Includes volatile register C2.
D2 4 Volatile (non-SOC)
D1 16 Non-Volatile (SOC)
D0 16 Non-Volatile (SOC)
D10 32 Non-Volatile (SOC)
D 36 Volatile (non-SOC) Includes volatile register D2.
Address Generation
Unit (AGU)
R0 24 Volatile (non-SOC)
R1 24 Volatile (non-SOC)
R2 24 Volatile (non-SOC)
R3 24 Volatile (non-SOC)
R4 24 Volatile (non-SOC)
R5 24 Non-volatile (SOC) If the compiler uses R5 as a
pointer, it becomes a volatile
register — its value can be
saved over called functions.
N 24 Volatile (non-SOC)
Table 6.3 Volatile and Non-Volatile Registers (continued)
Unit Register Size Type Comments