Subroutine linkage convention

The Subroutine Linkage Convention.

This article discusses the following:

Linkage convention overview
The subroutine linkage convention describes the machine state at subroutine entry and exit.
Calling routine's responsibilities
An assembler language program calls another program, the caller should not use the names of the called programs commands, functions, or procedures as global assembler language symbols.
Called routine's responsibilities
Prologs and epilogs are used in the called routines.
Traceback tags
The assembly (compiled) program needs traceback information for the debugger to examine if the program traps or crashes during the execution.
Example
Example of assembler code called by a C subroutine.
Using milicode routines
The milicode routines contain machine-dependent and performance-critical functions.

Parent topic: Assembling and linking a program