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How to pass variables from a C++ function into inline ASM

I'm having the trouble getting the inline assembler and/or linker of
Dev-Cpp to see my variable that's been passed into the C++ fn where the
inline ASM code is. Can anyone help me figure out how to get this to
work? The specific error is "[Linker error] undefined reference to
`val'". And here's my program:

#include <iostream>
#include <cstdlib>
using std::cout;
using std::cin;
using std::endl;
using std::system;

int Double(int val)
asm("mov eax,val \n");
asm("add eax,eax \n");
asm("mov val,eax \n");
return val;

int main()
int val;
cout << "Enter a value: " << endl;
cin >val;
cout << val << "*2=" << Double(val) << endl;
system("PAUSE") ;

If anyone could help, that'd be great. Thanks!!!!

Aug 2 '06
10 13538

Phil Carmody wrote:
"Protoman" <sp******@crayn e.orgwrites:
Tim Roberts wrote:
Do you have a Linux system handy? Almost everything I learned about gcc
inline assembler, I learned from two places: perusing the include files in
a Linux distribution, and this very handy tutorial:
OK, I fixed that, now it says: 21 C:\Dev-Cpp\ASM.cpp output operand
constraint lacks `=' Which one is output?

Oh for fuck's sake. That is answered quite near the top of the page
Tim pointed you towards. From this we can only infer bad things
about the intelligence of people who think "Win-XP rules". Thanks
for reinforcing the stereotype.

The man who is always worrying about whether or not his soul would be
damned generally has a soul that isn't worth a damn.
-- Oliver Wendell Holmes, Sr. (1809-1894), American physician and writer
Actually, about two nanoseconds after I posted "WinXP rules!!!!", I
found and fixed the problem myself, but my router went down, so I
couldn't tell you. Bye.

Aug 7 '06 #11

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