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unroll byteSwap() loop for common case

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This commit is contained in:
Josh Coalson 2007-03-22 03:14:12 +00:00
parent be5e19b964
commit feeca21bde
1 changed files with 30 additions and 7 deletions
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37
src/libFLAC/md5.c
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@ -138,16 +138,39 @@ static void FLAC__MD5Transform(FLAC__uint32 buf[4], FLAC__uint32 const in[16])
#if WORDS_BIGENDIAN
//@@@@@@ OPT: use bswap/intrinsics
FLaC__INLINE static void byteSwap(FLAC__uint32 *buf, unsigned words)
static void byteSwap(FLAC__uint32 *buf, unsigned words)
{
register FLAC__uint32 x;
do {
FLAC__byte *p = (FLAC__byte *)buf;
*buf++ = (FLAC__uint32)((unsigned)p[3] << 8 | p[2]) << 16 | ((unsigned)p[1] << 8 | p[0]);
p += 4;
x = *buf;
x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff);
*buf++ = (x >> 16) | (x << 16);
} while (--words);
}
static void byteSwapX16(FLAC__uint32 *buf)
{
register FLAC__uint32 x;
x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf++ = (x >> 16) | (x << 16);
x = *buf; x = ((x << 8) & 0xff00ff00) | ((x >> 8) & 0x00ff00ff); *buf = (x >> 16) | (x << 16);
}
#else
#define byteSwap(buf, words)
#define byteSwapX16(buf)
#endif
/*
@ -171,7 +194,7 @@ static void FLAC__MD5Update(FLAC__MD5Context *ctx, FLAC__byte const *buf, unsign
}
/* First chunk is an odd size */
memcpy((FLAC__byte *)ctx->in + 64 - t, buf, t);
byteSwap(ctx->in, 16);
byteSwapX16(ctx->in);
FLAC__MD5Transform(ctx->buf, ctx->in);
buf += t;
len -= t;
@ -179,7 +202,7 @@ static void FLAC__MD5Update(FLAC__MD5Context *ctx, FLAC__byte const *buf, unsign
/* Process data in 64-byte chunks */
while (len >= 64) {
memcpy(ctx->in, buf, 64);
byteSwap(ctx->in, 16);
byteSwapX16(ctx->in);
FLAC__MD5Transform(ctx->buf, ctx->in);
buf += 64;
len -= 64;
@ -224,7 +247,7 @@ void FLAC__MD5Final(FLAC__byte digest[16], FLAC__MD5Context *ctx)
if (count < 0) { /* Padding forces an extra block */
memset(p, 0, count + 8);
byteSwap(ctx->in, 16);
byteSwapX16(ctx->in);
FLAC__MD5Transform(ctx->buf, ctx->in);
p = (FLAC__byte *)ctx->in;
count = 56;