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(gcc-295.info)Registers

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Register Usage
==============

   This section explains how to describe what registers the target
machine has, and how (in general) they can be used.

   The description of which registers a specific instruction can use is
done with register classes; see Note: Register Classes.  For
information on using registers to access a stack frame, see Note: Frame
Registers.  For passing values in registers, see Note: Register
Arguments.  For returning values in registers, see Note: Scalar
Return.

Register Basics

Number and kinds of registers.

Allocation Order

Order in which registers are allocated.

Values in Registers

What kinds of values each reg can hold.

Leaf Functions

Renumbering registers for leaf functions.

Stack Registers

Handling a register stack such as 80387.

Obsolete Register Macros

Macros formerly used for the 80387.