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-rw-r--r--src/libmad/fixed.c48
1 files changed, 46 insertions, 2 deletions
diff --git a/src/libmad/fixed.c b/src/libmad/fixed.c
index d02a7299e..ae02360ca 100644
--- a/src/libmad/fixed.c
+++ b/src/libmad/fixed.c
@@ -1,6 +1,6 @@
/*
* libmad - MPEG audio decoder library
- * Copyright (C) 2000-2001 Robert Leslie
+ * Copyright (C) 2000-2004 Underbit Technologies, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
@@ -16,7 +16,7 @@
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
- * $Id: fixed.c,v 1.2 2002/04/30 18:46:58 miguelfreitas Exp $
+ * $Id: fixed.c,v 1.3 2004/04/22 00:22:36 miguelfreitas Exp $
*/
# ifdef HAVE_CONFIG_H
@@ -35,3 +35,47 @@ mad_fixed_t mad_f_abs(mad_fixed_t x)
{
return x < 0 ? -x : x;
}
+
+/*
+ * NAME: fixed->div()
+ * DESCRIPTION: perform division using fixed-point math
+ */
+mad_fixed_t mad_f_div(mad_fixed_t x, mad_fixed_t y)
+{
+ mad_fixed_t q, r;
+ unsigned int bits;
+
+ q = mad_f_abs(x / y);
+
+ if (x < 0) {
+ x = -x;
+ y = -y;
+ }
+
+ r = x % y;
+
+ if (y < 0) {
+ x = -x;
+ y = -y;
+ }
+
+ if (q > mad_f_intpart(MAD_F_MAX) &&
+ !(q == -mad_f_intpart(MAD_F_MIN) && r == 0 && (x < 0) != (y < 0)))
+ return 0;
+
+ for (bits = MAD_F_FRACBITS; bits && r; --bits) {
+ q <<= 1, r <<= 1;
+ if (r >= y)
+ r -= y, ++q;
+ }
+
+ /* round */
+ if (2 * r >= y)
+ ++q;
+
+ /* fix sign */
+ if ((x < 0) != (y < 0))
+ q = -q;
+
+ return q << bits;
+}