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check/gst/gstutils.c: Updated check, add some scaling accuracy checking code.
Original commit message from CVS: * check/gst/gstutils.c: (GST_START_TEST): Updated check, add some scaling accuracy checking code. * gst/gstutils.c: (gst_util_div128_64), (gst_util_uint64_scale_int64), (gst_util_uint64_scale), (gst_util_uint64_scale_int): Fix 6 times faster division code. Optimize for common 1/1 and less common X/1 cases.
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4 changed files with 65 additions and 42 deletions
11
ChangeLog
11
ChangeLog
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@ -1,3 +1,14 @@
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2005-11-28 Wim Taymans <wim@fluendo.com>
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* check/gst/gstutils.c: (GST_START_TEST):
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Updated check, add some scaling accuracy checking code.
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* gst/gstutils.c: (gst_util_div128_64),
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(gst_util_uint64_scale_int64), (gst_util_uint64_scale),
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(gst_util_uint64_scale_int):
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Fix 6 times faster division code. Optimize for common
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1/1 and less common X/1 cases.
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2005-11-28 Wim Taymans <wim@fluendo.com>
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* check/gst/gstutils.c: (GST_START_TEST), (gst_utils_suite):
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@ -236,19 +236,35 @@ GST_START_TEST (test_math_scale_uint64)
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GST_START_TEST (test_math_scale_random)
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{
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guint64 val, num, denom, res;;
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guint64 val, num, denom, res;
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GRand *rand;
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gint i;
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rand = g_rand_new ();
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i = 1000;
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i = 1000000;
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while (i--) {
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guint64 check, diff;
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val = ((guint64) g_rand_int (rand)) << 32 | g_rand_int (rand);
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num = ((guint64) g_rand_int (rand)) << 32 | g_rand_int (rand);
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denom = ((guint64) g_rand_int (rand)) << 32 | g_rand_int (rand);
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res = gst_util_uint64_scale (val, num, denom);
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check = gst_gdouble_to_guint64 (gst_guint64_to_gdouble (val) *
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gst_guint64_to_gdouble (num) / gst_guint64_to_gdouble (denom));
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if (res < G_MAXUINT64 && check < G_MAXUINT64) {
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if (res > check)
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diff = res - check;
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else
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diff = check - res;
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/* some arbitrary value, really.. someone do the proper math to get
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* the upper bound */
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if (diff > 20000)
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fail_if (diff > 20000);
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}
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}
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g_rand_free (rand);
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@ -356,36 +356,6 @@ typedef union
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} l;
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} GstUInt64;
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static guint64
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gst_util_div128_64_iterate (GstUInt64 c1, GstUInt64 c0, guint64 denom)
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{
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gint i;
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gint64 mask;
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GstUInt64 a0;
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/* full 128/64 case, very slow... */
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/* quotient is c1, c0 */
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a0.ll = 0; /* remainder a0 */
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/* This can be done faster, inspiration in Hacker's Delight p152 */
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for (i = 0; i < 128; i++) {
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/* shift 192 bits remainder:quotient, we only need to
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* check the top bit since denom is only 64 bits. */
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/* sign extend top bit into mask */
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mask = ((gint32) a0.l.high) >> 31;
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mask |= (a0.ll = (a0.ll << 1) | (c1.l.high >> 31));
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c1.ll = (c1.ll << 1) | (c0.l.high >> 31);
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c0.ll <<= 1;
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/* if remainder >= denom or top bit was set */
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if (mask >= denom) {
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a0.ll -= denom;
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c0.ll += 1;
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}
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}
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return c0.ll;
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}
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/* based on Hacker's Delight p152 */
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static guint64
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gst_util_div128_64 (GstUInt64 c1, GstUInt64 c0, guint64 denom)
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@ -409,10 +379,12 @@ gst_util_div128_64 (GstUInt64 c1, GstUInt64 c0, guint64 denom)
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s += (s >> 8);
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s = (s + (s >> 16)) & 0x3f;
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/* normalize divisor and dividend */
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v.ll <<= s;
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c1.ll = (c1.ll << s) | ((c0.l.high >> (32 - s)) & (-s >> 31));
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c0.ll <<= s;
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if (s > 0) {
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/* normalize divisor and dividend */
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v.ll <<= s;
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c1.ll = (c1.ll << s) | (c0.l.high >> (32 - s));
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c0.ll <<= s;
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}
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q1.ll = c1.ll / v.l.high;
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rhat.ll = c1.ll - q1.ll * v.l.high;
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@ -489,6 +461,11 @@ gst_util_uint64_scale_int64 (guint64 val, guint64 num, guint64 denom)
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if (c1.ll >= denom)
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goto overflow;
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/* shortcut for division by 1, c1.ll should be 0 because of the
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* overflow check above. */
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if (denom == 1)
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return c0.ll;
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/* and 128/64 bits division, result fits 64 bits */
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if (denom <= G_MAXUINT32) {
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guint32 den = (guint32) denom;
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@ -501,10 +478,7 @@ gst_util_uint64_scale_int64 (guint64 val, guint64 num, guint64 denom)
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result.l.high = c1.ll / den;
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result.l.low = c0.ll / den;
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} else {
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if (TRUE)
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result.ll = gst_util_div128_64_iterate (c1, c0, denom);
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else
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result.ll = gst_util_div128_64 (c1, c0, denom);
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result.ll = gst_util_div128_64 (c1, c0, denom);
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}
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return result.ll;
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@ -534,6 +508,9 @@ gst_util_uint64_scale (guint64 val, guint64 num, guint64 denom)
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if (num == 0)
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return 0;
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if (num == 1 && denom == 1)
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return val;
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/* if the denom is high, we need to do a 64 muldiv */
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if (denom > G_MAXINT32)
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goto do_int64;
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@ -581,6 +558,9 @@ gst_util_uint64_scale_int (guint64 val, gint num, gint denom)
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if (num == 0)
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return 0;
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if (num == 1 && denom == 1)
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return val;
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if (val <= G_MAXUINT32) {
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/* simple case */
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result.ll = val * num / denom;
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@ -236,19 +236,35 @@ GST_START_TEST (test_math_scale_uint64)
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GST_START_TEST (test_math_scale_random)
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{
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guint64 val, num, denom, res;;
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guint64 val, num, denom, res;
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GRand *rand;
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gint i;
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rand = g_rand_new ();
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i = 1000;
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i = 1000000;
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while (i--) {
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guint64 check, diff;
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val = ((guint64) g_rand_int (rand)) << 32 | g_rand_int (rand);
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num = ((guint64) g_rand_int (rand)) << 32 | g_rand_int (rand);
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denom = ((guint64) g_rand_int (rand)) << 32 | g_rand_int (rand);
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res = gst_util_uint64_scale (val, num, denom);
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check = gst_gdouble_to_guint64 (gst_guint64_to_gdouble (val) *
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gst_guint64_to_gdouble (num) / gst_guint64_to_gdouble (denom));
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if (res < G_MAXUINT64 && check < G_MAXUINT64) {
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if (res > check)
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diff = res - check;
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else
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diff = check - res;
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/* some arbitrary value, really.. someone do the proper math to get
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* the upper bound */
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if (diff > 20000)
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fail_if (diff > 20000);
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}
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}
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g_rand_free (rand);
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