Insert Assembly Code into C++?

Question

Hi, every one,
I am writing a segment of assembly code inserted into the C++ code. During the compiling using Solatis Sparc v8 C++ compiler, I felt a bit confused at the following error:
Linking
Undefined Symbol first referenced in file
lock ..../libatsup.so( this is my created lib)
My code looks like:
Error atomic_lock(volatile int *lock)
asm("retry:");
asm("ldstub [lock], %l0");
My question is how to declare the variable "lock" in the atomic_lock?
Any help will be appreciated.
-Yuzhong

Answer 1

Sorry for the confusion. I was assuming that your assembly routine is simple enough to be leaf routine. So, it need not have a save in the prologue. If you have a save, your input args. will be in %i0-%i6. Depending on the prototype of the atomic lock function you are writing, access the arguments in %i0 and so on. If you don't need new register window, (don't call other function and no stack space needed) the args. will be in %o0-%o6. The easiest way is to write a similar(skeleton) code and compile it into assembly and fill in atomic instructions.
You have to declare the function as
extern "C" {
void atomic_op(int *lock,......); // exact code depends on your design
in other files where you refer it.
-Ananth.