On 8/7/10 12:32 PM, Parmenides wrote:
asmlinage void IRQ3;
asm(...);
yes, we get it exactly. But, asm(...) is just a statement and in my
opinion, it should belong to some function body. While the first line
merely declare a function without definition owing to the semicolon
behind IRQ3.
2010/8/8 Daniel (Youngwhan) Song<breadncup@xxxxxxxxx>:
On 8/7/10 6:05 AM, Parmenides wrote:
Oh, my question is really no clear. Actually, there is a simicolon at
the end of the declaration of IRQ0x01_interrupt, while the statement
of __asm__ is not enclosed by a pair of brace, namely that no the body
of function. So, I don't think this is a traditional definition of
function.
ps: the original excerpt of the code is a macro like this:
#define BUILD_IRQ(nr) \
asmlinkage void IRQ_NAME(nr); \
__asm__( \
"\n"__ALIGN_STR"\n" \
SYMBOL_NAME_STR(IRQ) #nr "_interrupt:\n\t" \
"pushl $"#nr"-256\n\t" \
"jmp common_interrupt");
2010/8/7 Mulyadi Santosa<mulyadi.santosa@xxxxxxxxx>:
On Fri, Aug 6, 2010 at 02:52, Parmenides<mobile.parmenides@xxxxxxxxx>
wrote:
Hi,
In i8259.c, there is an odd funciton definition as follows:
asmlinkage void IRQ0x01_interrupt();
__asm__( ...);
you mean asmlinkage thing? here's the explanation:
http://kernelnewbies.org/FAQ/asmlinkage
And if you ask about __asm__, that's, AFAIK, a way to directly embed
assembly instruction into your C code.
--
regards,
Mulyadi Santosa
Freelance Linux trainer and consultant
blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com
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Hi Parmendies,
IRQ_NAME defined as IRQ##nr, so it declares void IRQ##nr, and the next
assembly code is performed by BUILD_IRQ definition. So, if you use
BUILD_IRQ(3), it extracts like
asmlinage void IRQ3;
asm(...);
Daniel
Probably, I don't quite understand your question on here.
asmlinage void IRQ3; is not a function declaration. This is declaration
of variable. not function.
asm() is a statement as you understand.
As long as BUILD_IRQ() is used in a function like
int test_func(void) {
BUILD_IRQ(3)
...
}
, there is no problem of the definition. It will be extracted like
int test_func(void) {
asmlinage void IRQ3;
asm(...);
...
}
I don't understand why a pair of brace is needed in the definition. Am I
missing or misunderstand your question?
Daniel
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