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-rw-r--r--drivers/staging/echo/bit_operations.h253
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diff --git a/drivers/staging/echo/bit_operations.h b/drivers/staging/echo/bit_operations.h
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+/*
+ * 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 General Public License version 2, 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU 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 1.11 2006/11/28 15:37:03 steveu Exp $
+ */
+
+/*! \file */
+
+#if !defined(_BIT_OPERATIONS_H_)
+#define _BIT_OPERATIONS_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if defined(__i386__) || defined(__x86_64__)
+/*! \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)
+{
+ int res;
+
+ __asm__ (" xorl %[res],%[res];\n"
+ " decl %[res];\n"
+ " bsrl %[bits],%[res]\n"
+ : [res] "=&r" (res)
+ : [bits] "rm" (bits));
+ return res;
+}
+/*- 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;
+
+ __asm__ (" xorl %[res],%[res];\n"
+ " decl %[res];\n"
+ " bsfl %[bits],%[res]\n"
+ : [res] "=&r" (res)
+ : [bits] "rm" (bits));
+ return res;
+}
+/*- End of function --------------------------------------------------------*/
+#else
+static __inline__ int top_bit(unsigned int bits)
+{
+ int i;
+
+ if (bits == 0)
+ return -1;
+ i = 0;
+ if (bits & 0xFFFF0000)
+ {
+ bits &= 0xFFFF0000;
+ i += 16;
+ }
+ if (bits & 0xFF00FF00)
+ {
+ bits &= 0xFF00FF00;
+ i += 8;
+ }
+ if (bits & 0xF0F0F0F0)
+ {
+ bits &= 0xF0F0F0F0;
+ i += 4;
+ }
+ if (bits & 0xCCCCCCCC)
+ {
+ bits &= 0xCCCCCCCC;
+ i += 2;
+ }
+ if (bits & 0xAAAAAAAA)
+ {
+ bits &= 0xAAAAAAAA;
+ i += 1;
+ }
+ return i;
+}
+/*- End of function --------------------------------------------------------*/
+
+static __inline__ int bottom_bit(unsigned int bits)
+{
+ int i;
+
+ if (bits == 0)
+ return -1;
+ i = 32;
+ if (bits & 0x0000FFFF)
+ {
+ bits &= 0x0000FFFF;
+ i -= 16;
+ }
+ if (bits & 0x00FF00FF)
+ {
+ bits &= 0x00FF00FF;
+ i -= 8;
+ }
+ if (bits & 0x0F0F0F0F)
+ {
+ bits &= 0x0F0F0F0F;
+ i -= 4;
+ }
+ if (bits & 0x33333333)
+ {
+ bits &= 0x33333333;
+ i -= 2;
+ }
+ if (bits & 0x55555555)
+ {
+ bits &= 0x55555555;
+ i -= 1;
+ }
+ return i;
+}
+/*- End of function --------------------------------------------------------*/
+#endif
+
+/*! \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__)
+ /* 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. */
+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. */
+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. */
+uint32_t bit_reverse_4bytes(uint32_t data);
+
+/*! \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. */
+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. */
+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. */
+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__)
+ 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 --------------------------------------------------------*/
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+/*- End of file ------------------------------------------------------------*/
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