--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spandsp-0.0.6pre17/src/spandsp/saturated.h	Fri Jun 25 15:50:58 2010 +0200
@@ -0,0 +1,223 @@
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * saturated.h - General saturated arithmetic routines.
+ *
+ * Written by Steve Underwood <steveu@coppice.org>
+ *
+ * Copyright (C) 2001, 2008 Steve Underwood
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License version 2.1,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * $Id: saturated.h,v 1.4 2009/02/05 12:21:36 steveu Exp $
+ */
+
+/*! \file */
+
+#if !defined(_SPANDSP_SATURATED_H_)
+#define _SPANDSP_SATURATED_H_
+
+/*! \page saturated_page Saturated arithmetic
+
+\section saturated_page_sec_1 What does it do?
+
+
+\section saturated_page_sec_2 How does it work?
+
+*/
+
+#if defined(__cplusplus)
+extern "C"
+{
+#endif
+
+static __inline__ int16_t saturate(int32_t amp)
+{
+    int16_t amp16;
+
+    /* Hopefully this is optimised for the common case - not clipping */
+    amp16 = (int16_t) amp;
+    if (amp == amp16)
+        return amp16;
+    if (amp > INT16_MAX)
+        return INT16_MAX;
+    return INT16_MIN;
+}
+/*- End of function --------------------------------------------------------*/
+
+/*! Saturate to 15 bits, rather than the usual 16 bits. This is often a useful function. */
+static __inline__ int16_t saturate15(int32_t amp)
+{
+    if (amp > 16383)
+        return 16383;
+    if (amp < -16384)
+        return -16384;
+    return (int16_t) amp;
+}
+/*- End of function --------------------------------------------------------*/
+
+static __inline__ int16_t fsaturatef(float famp)
+{
+    if (famp > (float) INT16_MAX)
+        return INT16_MAX;
+    if (famp < (float) INT16_MIN)
+        return INT16_MIN;
+    return (int16_t) lrintf(famp);
+}
+/*- End of function --------------------------------------------------------*/
+
+static __inline__ int16_t fsaturate(double damp)
+{
+    if (damp > (double) INT16_MAX)
+        return INT16_MAX;
+    if (damp < (double) INT16_MIN)
+        return INT16_MIN;
+    return (int16_t) lrint(damp);
+}
+/*- End of function --------------------------------------------------------*/
+
+/* Saturate to a 16 bit integer, using the fastest float to int conversion */
+static __inline__ int16_t ffastsaturatef(float famp)
+{
+    if (famp > (float) INT16_MAX)
+        return INT16_MAX;
+    if (famp < (float) INT16_MIN)
+        return INT16_MIN;
+    return (int16_t) lfastrintf(famp);
+}
+/*- End of function --------------------------------------------------------*/
+
+/* Saturate to a 16 bit integer, using the fastest double to int conversion */
+static __inline__ int16_t ffastsaturate(double damp)
+{
+    if (damp > (double) INT16_MAX)
+        return INT16_MAX;
+    if (damp < (double) INT16_MIN)
+        return INT16_MIN;
+    return (int16_t) lfastrint(damp);
+}
+/*- End of function --------------------------------------------------------*/
+
+/* Saturate to a 16 bit integer, using the closest float to int conversion */
+static __inline__ float ffsaturatef(float famp)
+{
+    if (famp > (float) INT16_MAX)
+        return (float) INT16_MAX;
+    if (famp < (float) INT16_MIN)
+        return (float) INT16_MIN;
+    return famp;
+}
+/*- End of function --------------------------------------------------------*/
+
+/* Saturate to a 16 bit integer, using the closest double to int conversion */
+static __inline__ double ffsaturate(double famp)
+{
+    if (famp > (double) INT16_MAX)
+        return (double) INT16_MAX;
+    if (famp < (double) INT16_MIN)
+        return (double) INT16_MIN;
+    return famp;
+}
+/*- End of function --------------------------------------------------------*/
+
+static __inline__ int16_t saturated_add16(int16_t a, int16_t b)
+{
+#if defined(__GNUC__)  &&  defined(__i386__)
+    __asm__ __volatile__(
+        " addw %2,%0;\n"
+        " jno 0f;\n"
+        " movw $0x7fff,%0;\n"
+        " adcw $0,%0;\n"
+        "0:"
+        : "=r" (a)
+        : "0" (a), "ir" (b)
+        : "cc"
+    );
+    return a;
+#else
+    return saturate((int32_t) a + (int32_t) b);
+#endif
+}
+/*- End of function --------------------------------------------------------*/
+
+static __inline__ int32_t saturated_add32(int32_t a, int32_t b)
+{
+#if defined(__GNUC__)  &&  defined(__i386__)
+    __asm__ __volatile__(
+        " addl %2,%0;\n"
+        " jno 0f;\n"
+        " movl $0x7fffffff,%0;\n"
+        " adcl $0,%0;\n"
+        "0:"
+        : "=r" (a)
+        : "0" (a), "ir" (b)
+        : "cc"
+    );
+    return a;
+#else
+    uint32_t A;
+
+    if (a < 0)
+    {
+        if (b >= 0)
+            return  a + b;
+        /*endif*/
+        A = (uint32_t) -(a + 1) + (uint32_t) -(b + 1);
+        return (A >= INT32_MAX)  ?  INT32_MIN  :  -(int32_t) A - 2;
+    }
+    /*endif*/
+    if (b <= 0)
+        return  a + b;
+    /*endif*/
+    A = (uint32_t) a + (uint32_t) b;
+    return (A > INT32_MAX)  ?  INT32_MAX  :  A;
+#endif
+}
+/*- End of function --------------------------------------------------------*/
+
+static __inline__ int16_t saturated_sub16(int16_t a, int16_t b)
+{
+    return saturate((int32_t) a - (int32_t) b);
+}
+/*- End of function --------------------------------------------------------*/
+
+static __inline__ int16_t saturated_mul16(int16_t a, int16_t b)
+{
+    if (a == INT16_MIN  &&  b == INT16_MIN)
+        return INT16_MAX;
+    /*endif*/
+    return (int16_t) (((int32_t) a*(int32_t) b) >> 15);
+}
+/*- End of function --------------------------------------------------------*/
+
+static __inline__ int32_t saturated_mul_16_32(int16_t a, int16_t b)
+{
+    return ((int32_t) a*(int32_t) b) << 1;
+}
+/*- End of function --------------------------------------------------------*/
+
+static __inline__ int16_t saturated_abs16(int16_t a)
+{
+    return (a == INT16_MIN)  ?  INT16_MAX  :  (int16_t) abs(a);
+}
+/*- End of function --------------------------------------------------------*/
+
+#if defined(__cplusplus)
+}
+#endif
+
+#endif
+/*- End of file ------------------------------------------------------------*/