/* $NetBSD: bswap64.c,v 1.3 2009/03/16 05:59:21 cegger Exp $ */ /* * Written by Manuel Bouyer <bouyer@NetBSD.org>. * Public domain. */ #include <sys/cdefs.h> #if defined(LIBC_SCCS) && !defined(lint) __RCSID("$NetBSD: bswap64.c,v 1.3 2009/03/16 05:59:21 cegger Exp $"); #endif /* LIBC_SCCS and not lint */ #include <sys/types.h> #include <machine/bswap.h> #undef bswap64 uint64_t bswap64(uint64_t x) { #ifdef _LP64 /* * Assume we have wide enough registers to do it without touching * memory. */ return ( (x << 56) & 0xff00000000000000UL ) | ( (x << 40) & 0x00ff000000000000UL ) | ( (x << 24) & 0x0000ff0000000000UL ) | ( (x << 8) & 0x000000ff00000000UL ) | ( (x >> 8) & 0x00000000ff000000UL ) | ( (x >> 24) & 0x0000000000ff0000UL ) | ( (x >> 40) & 0x000000000000ff00UL ) | ( (x >> 56) & 0x00000000000000ffUL ); #else /* * Split the operation in two 32bit steps. */ uint32_t tl, th; th = bswap32((uint32_t)(x & 0x00000000ffffffffULL)); tl = bswap32((uint32_t)((x >> 32) & 0x00000000ffffffffULL)); return ((uint64_t)th << 32) | tl; #endif } |