Re: GCC and Linux

Eric Youngdale (eric@andante.jic.com)
Mon, 28 Apr 1997 22:01:38 -0400

>Gcc must know precisely how the stack is layed out in order to know
>where local values on the stack are, and where it can stick
>temporaries for when register contention is larger than can fit
>completely in the register set during a block of code.

Actually something like this would work:

/*... */

ptr = alloca(4);
pushfl(ptr);

/*... */

popfl(ptr);
alloca(-4);

No, this is not a serious suggestion, but GCC can grok the stack pointer moving
while you are in the middle of a function. Believe it or not, some implementations of
alloca() do the right thing when given a negative argument :-).

-Eric