I have C-program with assembly insert. Here is code: main.c:
#include <stdio.h>
int f() {
int a = 0, b;
__asm__ (".intel_syntax noprefix\n\t"
"mov edx, 1\n\t"
:"=r"(b)
:"r"(a)
:"eax"
);
return b;
}
int main() {
printf("%d", f());
}
I have found out how to compile this code (gcc -std=c11 -S main.c -o main), but when i run it (./main) - here is a problem in terminal: bash: ./main: Permission denied.
When I try to compile it without -S flag, I get many unreasonable mistakes:
/tmp/ccw3H0Mb.s: Assembler messages:
/tmp/ccw3H0Mb.s:23: Error: Instruction does not exist: «movl%edx,-4(%rbp)»
/tmp/ccw3H0Mb.s:24: Error: Instruction does not exist: «movl4(%rbp),%eax»
/tmp/ccw3H0Mb.s:46: Error: Instruction does not exist: «movl$0,%eax»
/tmp/ccw3H0Mb.s:48: Error: Instruction does not exist: «movl%eax,%esi»
/tmp/ccw3H0Mb.s:49: Error: Garbage «(%rip)» after expression
/tmp/ccw3H0Mb.s:50: Error: Instruction does not exist: «movl$0,%eax»
/tmp/ccw3H0Mb.s:52: Error: Instruction does not exist: «movl$0,%eax»
What is the error and how can I fix it to run my code correctly? Thanks! :)
All I needed was just adding -masm=intel to the compilation command, and, of course, I removed -S flag (thanks to fuz). It is important because I am using Intel syntax, so gcc must be awared about it.
Now it looks like:
gcc -std=c11 -masm=intel main.c -o main