* problem passing constants to inline asm
@ 2006-05-22 17:12 Stas Sergeev
2006-05-24 5:37 ` Ian Lance Taylor
0 siblings, 1 reply; 3+ messages in thread
From: Stas Sergeev @ 2006-05-22 17:12 UTC (permalink / raw)
To: gcc-help
Hi.
I am trying to write something like this:
asm volatile (".space %0\n" :: "i"(sizeof(var)));
but this doesn't work because "i" prepends the number
with the $ sign.
I've only found the following hack to cheat gcc:
asm volatile (".space %0\n" :: "m"(*(long*)sizeof(var)));
but that's quite nasty and doesn't work with -O0.
So, what is the right way of passing the constants to those
"Special Dot Symbols" of gas?
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: problem passing constants to inline asm
2006-05-22 17:12 problem passing constants to inline asm Stas Sergeev
@ 2006-05-24 5:37 ` Ian Lance Taylor
2006-05-24 16:36 ` Stas Sergeev
0 siblings, 1 reply; 3+ messages in thread
From: Ian Lance Taylor @ 2006-05-24 5:37 UTC (permalink / raw)
To: Stas Sergeev; +Cc: gcc-help
Stas Sergeev <stsp@aknet.ru> writes:
> I am trying to write something like this:
>
> asm volatile (".space %0\n" :: "i"(sizeof(var)));
>
> but this doesn't work because "i" prepends the number
> with the $ sign.
> I've only found the following hack to cheat gcc:
>
> asm volatile (".space %0\n" :: "m"(*(long*)sizeof(var)));
>
> but that's quite nasty and doesn't work with -O0.
>
> So, what is the right way of passing the constants to those
> "Special Dot Symbols" of gas?
Try %c0.
Ian
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: problem passing constants to inline asm
2006-05-24 5:37 ` Ian Lance Taylor
@ 2006-05-24 16:36 ` Stas Sergeev
0 siblings, 0 replies; 3+ messages in thread
From: Stas Sergeev @ 2006-05-24 16:36 UTC (permalink / raw)
To: Ian Lance Taylor; +Cc: gcc-help
Ian Lance Taylor wrote:
>> So, what is the right way of passing the constants to those
>> "Special Dot Symbols" of gas?
> Try %c0.
Thank you!
That's something that looks difficult to find in the gcc docs
though (if it is there at all).
^ permalink raw reply [flat|nested] 3+ messages in thread
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2006-05-22 17:12 problem passing constants to inline asm Stas Sergeev
2006-05-24 5:37 ` Ian Lance Taylor
2006-05-24 16:36 ` Stas Sergeev
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