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Fixes for 64-bit platforms; use of SSE builtin when available (patches by Gwenole Beauchesne).

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Tomas Frydrych 2007-08-21 09:25:09 +00:00
parent 155c22b93a
commit b1c040ce19
2 changed files with 24 additions and 4 deletions
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8
ChangeLog
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@ -1,3 +1,11 @@
2007-08-21 Tomas Frydrych <tf@openedhand.com>
* clutter/clutter-fixed.c:
(clutter_sqrti):
Fixes for 64-bit platforms; use of SSE builtin when available
(patches by Gwenole Beauchesne).
2007-08-20 Emmanuele Bassi <ebassi@openedhand.com>
* clutter/Makefile.am:

20
clutter/clutter-fixed.c
View File

@ -539,7 +539,12 @@ clutter_sqrtx (ClutterFixed x)
/* make even (2n) */
bit &= 0xfffffffe;
#else
/* TODO -- add i386 branch using bshr */
/* TODO -- add i386 branch using bshr
*
* NB: it's been said that the bshr instruction is poorly implemented
* and that it is possible to write a faster code in C using binary
* search -- at some point we should explore this
*/
int bit = 30;
while (bit >= 0)
{
@ -610,6 +615,12 @@ clutter_sqrtx (ClutterFixed x)
gint
clutter_sqrti (gint number)
{
#if defined __SSE2__
/* The GCC built-in with SSE2 (sqrtsd) is up to twice as fast as
* the pure integer code below. It is also more accurate.
*/
return __builtin_sqrt (number);
#else
/* This is a fixed point implementation of the Quake III sqrt algorithm,
* described, for example, at
* http://www.codemaestro.com/reviews/review00000105.html
@ -626,13 +637,13 @@ clutter_sqrti (gint number)
* elsewhere in clutter is not good enough, and 10.22 is used instead.
*/
ClutterFixed x;
unsigned long y_1; /* 10.22 fixed point */
unsigned long f = 0x600000; /* '1.5' as 10.22 fixed */
guint32 y_1; /* 10.22 fixed point */
guint32 f = 0x600000; /* '1.5' as 10.22 fixed */
union
{
float f;
unsigned long i;
guint32 i;
} flt, flt2;
flt.f = number;
@ -669,6 +680,7 @@ clutter_sqrti (gint number)
* better results than 0x200000.
*/
return (number * flt2.i + 0x1e3c68) >> 22;
#endif
}
/**