2.10 Predeclared core register names

Many of the core register names have synonyms.

The following table shows the predeclared core registers:

Table 2-2 Predeclared core registers

Register names
Meaning
r0-r15 and R0-R15
General purpose registers.
a1-a4
Argument, result or scratch registers. These are synonyms for R0 to R3
v1-v8
Variable registers. These are synonyms for R4 to R11.
sb and SB
Static base register. This is a synonym for R9.
ip and IP
Intra procedure call scratch register. This is a synonym for R12.
sp and SP
Stack pointer. This is a synonym for R13.
lr and LR
Link register. This is a synonym for R14.
pc and PC
Program counter. This is a synonym for R15.
With the exception of a1-a4 and v1-v8, you can write the registers either in all upper case or all lower case.
Related concepts
2.8 General-purpose registers
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