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 Register Classes. For information on using registers to access a stack frame, see Frame Registers. For passing values in registers, see Register Arguments. For returning values in registers, see 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. |