Messages in this thread | | | Date | Sun, 23 Jul 2000 17:51:10 -0700 | From | George Anzinger <> | Subject | Re: asm in C slightly OT |
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"H. Peter Anvin" wrote: > > Followup to: <39795FCE.65EE2768@pioneer.net> > By author: George Anzinger <george@pioneer.net> > In newsgroup: linux.dev.kernel > > > > The first line looks like a function proto type. It is unclear how it > > is related to the rest of the macro. This macro generates a bit of code > > that is not a function in any way. It has an entry label > > "common_interrupt" and ends with a jmp. What I really want to know is > > how to refer to a C variable inside of such a construct. The gcc > > documentation talks about how to do it in more standard asm. I would > > like, for example to add to the above macro, for example: > > > > "incl foo.bar" where bar is a member of structure foo. > > > > I know this could be done as: "incl foo+xxx" where xxx is the offset > > of bar in foo, but I would like the compiler to figure this for me so as > > to follow structure changes. > > > > RTFM(info gcc) > > asm("incl (%0)" :: "i" (&foo.bar));
I wish it was that easy. As it turns out the asm statement is not inside a function. This seems to turn off the ability to use the ":" construct. Why? Wish I knew. At this point I think I must use hand computed offsets for members of structures refered to from asm code that is not in a function.
George
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