[OpenBIOS] [RFC 3/3] ppc: RTAS WIP

[Andreas Färber]

Am 15.10.2010 um 12:26 schrieb Alexander Graf:

>
> On 15.10.2010, at 00:38, Alexander Graf wrote:
>
>>
>> Am 15.10.2010 um 00:17 schrieb Andreas Färber  
>> <andreas.faerber at web.de>:
>
> [snip]
>
>> /* saving non-volatile registers */
>>
>>> +    stw r13,  8(r4)
>>
>> I would recommend multiplying here:
>>
>> stw r13, (3 * 4)(r4)
>>
>> That makes it more readable.
>>
>>> +    stw r14, 12(r4)
>>> +    stw r15, 16(r4)
>>> +    stw r16, 20(r4)
>>> +    stw r17, 24(r4)
>>> +    stw r18, 28(r4)
>>> +    stw r19, 32(r4)
>>> +    stw r20, 36(r4)
>>> +    stw r21, 40(r4)
>>> +    stw r22, 44(r4)
>>> +    stw r23, 48(r4)
>>> +    stw r24, 52(r4)
>>> +    stw r25, 56(r4)
>>> +    stw r26, 60(r4)
>>> +    stw r27, 64(r4)
>>> +    stw r28, 68(r4)
>>> +    stw r29, 72(r4)
>>> +    stw r30, 76(r4)
>>> +    stw r31, 80(r4)
>
> Actually thinking about this a bit more, r13-r31 are already defined  
> non-volatile by the C ABI, so you can be sure that the C function  
> you're calling doesn't clobber them. You don't need to manually save/ 
> restore them :).
>
> Alex
>
>
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