[AD] fixdiv implementation

[Paul Suntsov <siegelords_abode@xxxxxxxxxx>]

Hello, this is in response to that bug report from a couple of days ago. I've made one that relies on the existence of a 64 bit long type but otherwise needs no FPU code. I wrapped it in some preprocessor directives as a result. This is the same situation as is with fixmul, so I figured it'd be fine. I guess eventually someone should make 32 bit only implementations, but this is better than nothing.

diff file attached.

SiegeLord


Index: fmaths.inl
===================================================================
--- fmaths.inl	(revision 10260)
+++ fmaths.inl	(working copy)
@@ -143,7 +143,7 @@
    })
 #endif	    /* fixmul() C implementations */
 
-
+#if (defined ALLEGRO_I386) || (!defined LONG_LONG)
 AL_INLINE(fixed, fixdiv, (fixed x, fixed y),
 {
    if (y == 0) {
@@ -153,8 +153,30 @@
    else
       return ftofix(fixtof(x) / fixtof(y));
 })
+#else
+AL_INLINE(fixed, fixdiv, (fixed x, fixed y),
+{
+   LONG_LONG lres = x;
+   if (y == 0) {
+      *allegro_errno = ERANGE;
+      return (x < 0) ? -0x7FFFFFFF : 0x7FFFFFFF;
+   }
+   lres <<= 16;
+   lres /= y;
+   if (lres > 0x7FFFFFFF) {
+      *allegro_errno = ERANGE;
+      return 0x7FFFFFFF;
+   }
+   else if (lres < -0x7FFFFFFF) {
+      *allegro_errno = ERANGE;
+      return 0x80000000;
+   }
+   else {
+      return (fixed)(lres);
+   }
+})
+#endif	    /* fixmul() C implementations */
 
-
 AL_INLINE(int, fixfloor, (fixed x),
 {
    /* (x >> 16) is not portable */