ARM SWI
Bryce Schober
bryceman@dpzone.com
Fri Dec 31 13:24:00 GMT 2004
Check out the GCC-Inline-Assembly-HOWTO here:
http://www.ibiblio.org/gferg/ldp/GCC-Inline-Assembly-HOWTO.html#s2
Also, more info on inline assembly operands constraints and such can be found in the gcc manual.
Vijay Deep wrote:
> hi all
>
> Can anyone tell what does %1, %2, %a3 mean in the following line
> "mov r0, %1; mov r1, %2; swi %a3; mov %0, r0". It occurs in the function
> below :
>
> do_AngelSWI (int reason, void * arg)
> {
> int value;
> //It enters here
> asm volatile ("mov r0, %1; mov r1, %2; swi %a3; mov %0, r0"
> : "=r" (value) /* Outputs */
> : "r" (reason), "r" (arg), "i" (AngelSWI) /* Inputs */
> : "r0", "r1", "r2", "r3", "ip", "lr", "memory", "cc"
> /* Clobbers r0 and r1, and lr if in supervisor mode */);
> /* Accordingly to page 13-77 of ARM DUI 0040D other
> registers
> can also be clobbered. Some memory positions may also
> be
> changed by a system call, so they should not be kept in
> registers. Note: we are assuming the manual is right
> and
> Angel is respecting the APCS. */
> return value;
> }
>
> Thanks in advance
> Regards
> Vijay Deep
>
>
>
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