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| author | rodrigc <rodrigc@FreeBSD.org> | 2011-06-10 01:13:15 +0000 |
|---|---|---|
| committer | rodrigc <rodrigc@FreeBSD.org> | 2011-06-10 01:13:15 +0000 |
| commit | 68430611dec10928172df6f7cdf8fe5a528ab10c (patch) | |
| tree | f3ae0bce016fd61867472addd3bf96c9eef03823 /lib/libstand | |
| parent | bd55770c9432e60436b620cca0048948daf2445b (diff) | |
| download | FreeBSD-src-68430611dec10928172df6f7cdf8fe5a528ab10c.zip FreeBSD-src-68430611dec10928172df6f7cdf8fe5a528ab10c.tar.gz | |
Obtain bswap64() function implementation from
version 1.3 of src/common/lib/libc/gen/bswap64.c in NetBSD.
Obtained from: NetBSD
Diffstat (limited to 'lib/libstand')
| -rw-r--r-- | lib/libstand/bswap.c | 36 |
1 files changed, 26 insertions, 10 deletions
diff --git a/lib/libstand/bswap.c b/lib/libstand/bswap.c index 212e2af..b8e6ffb 100644 --- a/lib/libstand/bswap.c +++ b/lib/libstand/bswap.c @@ -8,7 +8,7 @@ __FBSDID("$FreeBSD$"); #if defined(LIBC_SCCS) && !defined(lint) static char *rcsid = "$NetBSD: bswap32.c,v 1.1 1997/10/09 15:42:33 bouyer Exp $"; -static char *rcsid = "$NetBSD: bswap64.c,v 1.1 1997/10/09 15:42:33 bouyer Exp $"; +static char *rcsid = "$NetBSD: bswap64.c,v 1.3 2009/03/16 05:59:21 cegger Exp $"; #endif #include <sys/types.h> @@ -30,12 +30,28 @@ bswap32(u_int32_t x) u_int64_t bswap64(u_int64_t x) -{ - u_int32_t *p = (u_int32_t*)&x; - u_int32_t t; - t = bswap32(p[0]); - p[0] = bswap32(p[1]); - p[1] = t; - return 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. + */ + u_int32_t tl, th; + + th = bswap32((u_int32_t)(x & 0x00000000ffffffffULL)); + tl = bswap32((u_int32_t)((x >> 32) & 0x00000000ffffffffULL)); + return ((u_int64_t)th << 32) | tl; +#endif +} |
