30. Instruction Set Architecture - Registers

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R0 is hard-wired to a value of zero, and can be used as the target register for any instruction whose result is to be discarded. R0 can also be used as a source when a zero value is needed.

R31 is the default destination register used by jump instructions. Otherwise R31 can be used as a normal register.

All other registers are available for general-purpose use.

We will use generic assembly pseudo-code, e.g. DSUBI R3,R2,#100