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9.5 General-purpose Registers

How the CC-RH uses the general-purpose registers are as follows.

Table 9.5

Using General-purpose Registers

Register

Usage

r0

Used for operation as value of 0.

Base register of .data/.bss section reference

r1

caller save register

r2

caller save register

Reserved for system (OS) (Switched via option)

r3 (sp)

Stack pointer

r4 (gp)

Global pointer for PID

Fixed

r5 (tp)

Global pointer for constant data

caller save register

r6 to r19

caller save register

r20 to r29

callee save register

r30 (ep)

Element pointer

Fixed or callee save register (Switched via option)

r31 (lp)

Link pointer

callee save register