Miscellaneous Information; Register Classification; Callee Preserved Registers ("Preserved"); Dedicated Registers - Analog Devices VISUALDSP++ 3.5 Manual

Miscellaneous Information

This section contains a number of miscellaneous aspects of the design that
may be helpful in understanding stack functionality.
• Procedures without prototypes can be called successfully, provided
the argument types correspond properly. Prototypes are always
good programming practice. Programs that call library subroutines
should always include header files.
• There is no special interface for calling system library functions.
They use the standard calling convention.

Register Classification

This section describes all of the ADSP-219x processor registers. Registers
are listed in order of preferred allocation by the compiler

Callee Preserved Registers ("Preserved")

Registers ,
I2 I3
uses any of these registers must save (preserve) it and restore it.

Dedicated Registers

Certain registers have dedicated purposes and will not be used for other
things. Compiled code and libraries expect the dedicated registers to be
correct.

Caller Save Registers ("Scratch")

All registers not preserved or dedicated are scratch. A subroutine may use a
scratch register without having to save it.
VisualDSP++ 3.5 C/C++ Compiler and Library Manual
for ADSP-219x DSPs
, ,
I7 M0, M2 and M4
are preserved. A subroutine which
Compiler
1-161