lahf.c

The Valgrind distribution has multiple tools. The most popular is the memory checking tool (called M

#include <stdio.h>

extern int foo_1 ( void );
asm("\n"
"foo_1:\n"
"\tpushl $0\n"
"\tpopfl\n"
"\tmovl $0xFFFFFFFF, %eax\n"
"\tmovl $0x12345678, %edx\n"
"\tsubl %eax, %edx\n"
"\tlahf\n"
"\tret\n"
);

extern int foo_0 ( void );
asm("\n"
"foo_0:\n"
"\tpushl $0\n"
"\tpopfl\n"
"\tmovl $0x0, %eax\n"
"\tmovl $0x12345678, %edx\n"
"\tsubl %eax, %edx\n"
"\tlahf\n"
"\tret\n"
);

int main ( void )
{
  printf("0x%x\n", foo_0());
  printf("0x%x\n", foo_1());
  return 0;
}