13.5.5. Configuring SWI numbers

Angel requires one SWI in order to operate. The SWI is used to:

The SWI passes a reason code in r0 to determine the type of request. Depending on the SWI, additional arguments are passed in r1. Refer to Angel C library support SWIs more information.

The SWI number is different for ARM state and Thumb state. By default, the SWI numbers used are:

ARM state

0x123456

Thumb state

0xab

If you want to use either of these SWI numbers for your system you can reconfigure the SWI to use any of the available SWI numbers. If you change these values you must:

Refer to Chapter 9 Handling Processor Exceptions for more general information on handling SWIs.

In C, the Angel SWI numbers are defined in Angel\Source\arm.h as:

#define angel_SWI_ARM (0x123456)
#define angel_SWI_THUMB (0xAB)
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