Add an inline asm implementation of sum() for x86 CPUs

diff --git a/inline-asm-sum.c b/inline-asm-sum.c
index 4f9c2f0..a578ee7 100644 (file)
--- a/inline-asm-sum.c
+++ b/inline-asm-sum.c
@@ -21,7 +21,16 @@
 
 static int sum(int a, int b)
 {
+#if defined(__i386__) || defined(__x86_64__)
+       int ret;
+       __asm__("addl %2, %1\n\t"
+               : "=a"(ret)      /* %0 bound to %eax */
+               : "a"(a), "r"(b) /* %1 is 'a' bound to %eax, %2 is 'b' */
+               );
+       return ret;
+#else
        return a + b;
+#endif
 }
 
 int main(void)