#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;
+ 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;
+ 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;
+ 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;
+ 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.
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;
+ /* 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);
+ /* 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 word with the single set bit. */
static __inline__ uint32_t least_significant_one32(uint32_t x)
{
- return (x & (-(int32_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.
static __inline__ uint32_t most_significant_one32(uint32_t x)
{
#if defined(__i386__) || defined(__x86_64__)
- return 1 << top_bit(x);
+ return 1 << top_bit(x);
#else
- x = make_mask32(x);
- return (x ^ (x >> 1));
+ 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;
+ 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;
+ 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;
+ 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 ------------------------------------------------------------*/
projects / linux-2.6-omap-h63xx.git / blobdiff