Inside Macintosh: Mac OS Runtime Architectures /

Chapter 6 - The Mixed Mode Manager

In certain cases, your CFM-based application or shared library may need to call routines written in classic 68K code or vice versa. For example, a PowerPC runtime program may need to call a system software routine that runs as emulated classic 68K code. The Mixed Mode Manager allows you to make such routine calls transparently.

You should read this chapter if you have any of the following concerns:

• You are writing CFM-based code, but want to make sure that it remains compatible with existing classic 68K software (third-party plug-ins, for example).
• You need to maintain binary compatibility with old classic 68K routines or libraries whose source code is not available. You cannot recompile them for the CFM-based architecture, but you still want to be able to use the old routines.
• You are writing a low-level debugger or other tool that requires understanding of the Mixed Mode Manager.

This chapter assumes you have general programming knowledge of both the CFM-based runtime architecture and the classic 68K runtime architecture.

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Chapter Contents

Overview

Universal Procedure Pointers and Routine Descriptors

CFM-Based Code Originates the Call

Classic 68K Code Originates the Call

Mixed Mode Manager Performance Issues

Mode Switching Implementations

Calling PowerPC Code From Classic 68K Code

Calling Classic 68K Code From PowerPC Code

Calling CFM-68K Code From Classic 68K Code

Calling Classic 68K Code From CFM-68K Code