MINOR: tools: make my_htonll() more efficient on x86_64
The current construct was made when developing on a 32-bit machine.
Having a simple bswap operation replaced with 2 bswap, 2 shift and
2 or is quite of a waste of precious cycles... Let's provide a trivial
asm-based implementation for x86_64.
diff --git a/include/common/standard.h b/include/common/standard.h
index 74dc041..2645c44 100644
--- a/include/common/standard.h
+++ b/include/common/standard.h
@@ -1201,6 +1201,10 @@
*/
static inline unsigned long long my_htonll(unsigned long long a)
{
+#if defined(__x86_64__)
+ __asm__ volatile("bswap %0" : "=r"(a));
+ return a;
+#else
union {
struct {
unsigned int w1;
@@ -1209,6 +1213,7 @@
unsigned long long by64;
} w = { .by64 = a };
return ((unsigned long long)htonl(w.by32.w1) << 32) | htonl(w.by32.w2);
+#endif
}
/* Turns 64-bit value <a> from network byte order to host byte order. */