--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spandsp-0.0.6pre17/src/spandsp/bit_operations.h	Fri Jun 25 15:50:58 2010 +0200
@@ -0,0 +1,314 @@
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * bit_operations.h - Various bit level operations, such as bit reversal
+ *
+ * Written by Steve Underwood <steveu@coppice.org>
+ *
+ * Copyright (C) 2006 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: bit_operations.h,v 1.27 2009/07/10 13:15:56 steveu Exp $
+ */
+
+/*! \file */
+
+#if !defined(_SPANDSP_BIT_OPERATIONS_H_)
+#define _SPANDSP_BIT_OPERATIONS_H_
+
+#if defined(__i386__)  ||  defined(__x86_64__)
+#if !defined(__SUNPRO_C)  ||  (__SUNPRO_C >= 0x0590)
+#define SPANDSP_USE_86_ASM
+#endif
+#endif
+
+#if defined(__cplusplus)
+extern "C"
+{
+#endif
+
+/*! \brief Find the bit position of the highest set bit in a word
+    \param bits The word to be searched
+    \return The bit number of the highest set bit, or -1 if the word is zero. */
+static __inline__ int top_bit(unsigned int bits)
+{
+#if defined(SPANDSP_USE_86_ASM)
+    int res;
+
+    __asm__ (" xorl %[res],%[res];\n"
+             " decl %[res];\n"
+             " bsrl %[bits],%[res]\n"
+             : [res] "=&r" (res)
+             : [bits] "rm" (bits));
+    return res;
+#elif defined(__ppc__)  ||   defined(__powerpc__)
+    int res;
+
+    __asm__ ("cntlzw %[res],%[bits];\n"
+             : [res] "=&r" (res)
+             : [bits] "r" (bits));
+    return 31 - res;
+#elif defined(_M_IX86)
+    /* Visual Studio i386 */
+    __asm
+    {
+        xor eax, eax
+        dec eax
+        bsr eax, bits
+    }
+#elif defined(_M_X64)
+    /* Visual Studio x86_64 */
+    /* TODO: Need the appropriate x86_64 code */
+    int res;
+
+    if (bits == 0)
+        return -1;
+    res = 0;
+    if (bits & 0xFFFF0000)
+    {
+        bits &= 0xFFFF0000;
+        res += 16;
+    }
+    if (bits & 0xFF00FF00)
+    {
+        bits &= 0xFF00FF00;
+        res += 8;
+    }
+    if (bits & 0xF0F0F0F0)
+    {
+        bits &= 0xF0F0F0F0;
+        res += 4;
+    }
+    if (bits & 0xCCCCCCCC)
+    {
+        bits &= 0xCCCCCCCC;
+        res += 2;
+    }
+    if (bits & 0xAAAAAAAA)
+    {
+        bits &= 0xAAAAAAAA;
+        res += 1;
+    }
+    return res;
+#else
+    int res;
+
+    if (bits == 0)
+        return -1;
+    res = 0;
+    if (bits & 0xFFFF0000)
+    {
+        bits &= 0xFFFF0000;
+        res += 16;
+    }
+    if (bits & 0xFF00FF00)
+    {
+        bits &= 0xFF00FF00;
+        res += 8;
+    }
+    if (bits & 0xF0F0F0F0)
+    {
+        bits &= 0xF0F0F0F0;
+        res += 4;
+    }
+    if (bits & 0xCCCCCCCC)
+    {
+        bits &= 0xCCCCCCCC;
+        res += 2;
+    }
+    if (bits & 0xAAAAAAAA)
+    {
+        bits &= 0xAAAAAAAA;
+        res += 1;
+    }
+    return res;
+#endif
+}
+/*- End of function --------------------------------------------------------*/
+
+/*! \brief Find the bit position of the lowest set bit in a word
+    \param bits The word to be searched
+    \return The bit number of the lowest set bit, or -1 if the word is zero. */
+static __inline__ int bottom_bit(unsigned int bits)
+{
+    int res;
+    
+#if defined(SPANDSP_USE_86_ASM)
+    __asm__ (" xorl %[res],%[res];\n"
+             " decl %[res];\n"
+             " bsfl %[bits],%[res]\n"
+             : [res] "=&r" (res)
+             : [bits] "rm" (bits));
+    return res;
+#else
+    if (bits == 0)
+        return -1;
+    res = 31;
+    if (bits & 0x0000FFFF)
+    {
+        bits &= 0x0000FFFF;
+        res -= 16;
+    }
+    if (bits & 0x00FF00FF)
+    {
+        bits &= 0x00FF00FF;
+        res -= 8;
+    }
+    if (bits & 0x0F0F0F0F)
+    {
+        bits &= 0x0F0F0F0F;
+        res -= 4;
+    }
+    if (bits & 0x33333333)
+    {
+        bits &= 0x33333333;
+        res -= 2;
+    }
+    if (bits & 0x55555555)
+    {
+        bits &= 0x55555555;
+        res -= 1;
+    }
+    return res;
+#endif
+}
+/*- End of function --------------------------------------------------------*/
+
+/*! \brief Bit reverse a byte.
+    \param data The byte to be reversed.
+    \return The bit reversed version of data. */
+static __inline__ uint8_t bit_reverse8(uint8_t x)
+{
+#if defined(__i386__)  ||  defined(__x86_64__)  ||  defined(__ppc__)  ||  defined(__powerpc__)
+    /* If multiply is fast */
+    return ((x*0x0802U & 0x22110U) | (x*0x8020U & 0x88440U))*0x10101U >> 16;
+#else
+    /* If multiply is slow, but we have a barrel shifter */
+    x = (x >> 4) | (x << 4);
+    x = ((x & 0xCC) >> 2) | ((x & 0x33) << 2);
+    return ((x & 0xAA) >> 1) | ((x & 0x55) << 1);
+#endif
+}
+/*- End of function --------------------------------------------------------*/
+
+/*! \brief Bit reverse a 16 bit word.
+    \param data The word to be reversed.
+    \return The bit reversed version of data. */
+SPAN_DECLARE(uint16_t) bit_reverse16(uint16_t data);
+
+/*! \brief Bit reverse a 32 bit word.
+    \param data The word to be reversed.
+    \return The bit reversed version of data. */
+SPAN_DECLARE(uint32_t) bit_reverse32(uint32_t data);
+
+/*! \brief Bit reverse each of the four bytes in a 32 bit word.
+    \param data The word to be reversed.
+    \return The bit reversed version of data. */
+SPAN_DECLARE(uint32_t) bit_reverse_4bytes(uint32_t data);
+
+#if defined(__x86_64__)
+/*! \brief Bit reverse each of the eight bytes in a 64 bit word.
+    \param data The word to be reversed.
+    \return The bit reversed version of data. */
+SPAN_DECLARE(uint64_t) bit_reverse_8bytes(uint64_t data);
+#endif
+
+/*! \brief Bit reverse each bytes in a buffer.
+    \param to The buffer to place the reversed data in.
+    \param from The buffer containing the data to be reversed.
+    \param len The length of the data in the buffer. */
+SPAN_DECLARE(void) bit_reverse(uint8_t to[], const uint8_t from[], int len);
+
+/*! \brief Find the number of set bits in a 32 bit word.
+    \param x The word to be searched.
+    \return The number of set bits. */
+SPAN_DECLARE(int) one_bits32(uint32_t x);
+
+/*! \brief Create a mask as wide as the number in a 32 bit word.
+    \param x The word to be searched.
+    \return The mask. */
+SPAN_DECLARE(uint32_t) make_mask32(uint32_t x);
+
+/*! \brief Create a mask as wide as the number in a 16 bit word.
+    \param x The word to be searched.
+    \return The mask. */
+SPAN_DECLARE(uint16_t) make_mask16(uint16_t x);
+
+/*! \brief Find the least significant one in a word, and return a word
+           with just that bit set.
+    \param x The word to be searched.
+    \return The word with the single set bit. */
+static __inline__ uint32_t least_significant_one32(uint32_t x)
+{
+    return (x & (-(int32_t) x));
+}
+/*- End of function --------------------------------------------------------*/
+
+/*! \brief Find the most significant one in a word, and return a word
+           with just that bit set.
+    \param x The word to be searched.
+    \return The word with the single set bit. */
+static __inline__ uint32_t most_significant_one32(uint32_t x)
+{
+#if defined(__i386__)  ||  defined(__x86_64__)  ||  defined(__ppc__)  ||  defined(__powerpc__)
+    return 1 << top_bit(x);
+#else
+    x = make_mask32(x);
+    return (x ^ (x >> 1));
+#endif
+}
+/*- End of function --------------------------------------------------------*/
+
+/*! \brief Find the parity of a byte.
+    \param x The byte to be checked.
+    \return 1 for odd, or 0 for even. */
+static __inline__ int parity8(uint8_t x)
+{
+    x = (x ^ (x >> 4)) & 0x0F;
+    return (0x6996 >> x) & 1;
+}
+/*- End of function --------------------------------------------------------*/
+
+/*! \brief Find the parity of a 16 bit word.
+    \param x The word to be checked.
+    \return 1 for odd, or 0 for even. */
+static __inline__ int parity16(uint16_t x)
+{
+    x ^= (x >> 8);
+    x = (x ^ (x >> 4)) & 0x0F;
+    return (0x6996 >> x) & 1;
+}
+/*- End of function --------------------------------------------------------*/
+
+/*! \brief Find the parity of a 32 bit word.
+    \param x The word to be checked.
+    \return 1 for odd, or 0 for even. */
+static __inline__ int parity32(uint32_t x)
+{
+    x ^= (x >> 16);
+    x ^= (x >> 8);
+    x = (x ^ (x >> 4)) & 0x0F;
+    return (0x6996 >> x) & 1;
+}
+/*- End of function --------------------------------------------------------*/
+
+#if defined(__cplusplus)
+}
+#endif
+
+#endif
+/*- End of file ------------------------------------------------------------*/