src/vppinfra/bitops.h - fdio/vpp - Gitiles

 /*
  * Copyright (c) 2015 Cisco and/or its affiliates.
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at:
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 /*
   Copyright (c) 2005 Eliot Dresselhaus

   Permission is hereby granted, free of charge, to any person obtaining
   a copy of this software and associated documentation files (the
   "Software"), to deal in the Software without restriction, including
   without limitation the rights to use, copy, modify, merge, publish,
   distribute, sublicense, and/or sell copies of the Software, and to
   permit persons to whom the Software is furnished to do so, subject to
   the following conditions:

   The above copyright notice and this permission notice shall be
   included in all copies or substantial portions of the Software.

   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
   LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
   OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
   WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

 #ifndef included_clib_bitops_h
 #define included_clib_bitops_h

 #define SET_BIT(i)    (1 << i)
 #define GET_BIT(n, i) (n >> i) & 1U

 static_always_inline uword
 clear_lowest_set_bit (uword x)
 {
 #ifdef __BMI__
   return uword_bits > 32 ? _blsr_u64 (x) : _blsr_u32 (x);
 #else
   return x & (x - 1);
 #endif
 }

 static_always_inline uword
 get_lowest_set_bit (uword x)
 {
 #ifdef __BMI__
   return uword_bits > 32 ? _blsi_u64 (x) : _blsi_u32 (x);
 #else
   return x & -x;
 #endif
 }

 static_always_inline u8
 get_lowest_set_bit_index (uword x)
 {
   return uword_bits > 32 ? __builtin_ctzll (x) : __builtin_ctz (x);
 }

 /* Population count from Hacker's Delight. */
 always_inline uword
 count_set_bits (uword x)
 {
 #ifdef __POPCNT__
   return uword_bits > 32 ? __builtin_popcountll (x) : __builtin_popcount (x);
 #else
 #if uword_bits == 64
   const uword c1 = 0x5555555555555555;
   const uword c2 = 0x3333333333333333;
   const uword c3 = 0x0f0f0f0f0f0f0f0f;
 #else
   const uword c1 = 0x55555555;
   const uword c2 = 0x33333333;
   const uword c3 = 0x0f0f0f0f;
 #endif

   /* Sum 1 bit at a time. */
   x = x - ((x >> (uword) 1) & c1);

   /* 2 bits at a time. */
   x = (x & c2) + ((x >> (uword) 2) & c2);

   /* 4 bits at a time. */
   x = (x + (x >> (uword) 4)) & c3;

   /* 8, 16, 32 bits at a time. */
   x = x + (x >> (uword) 8);
   x = x + (x >> (uword) 16);
 #if uword_bits == 64
   x = x + (x >> (uword) 32);
 #endif

   return x & (2 * BITS (uword) - 1);
 #endif
 }

 #if uword_bits == 64
 #define count_leading_zeros(x) __builtin_clzll (x)
 #else
 #define count_leading_zeros(x) __builtin_clzll (x)
 #endif

 #define count_trailing_zeros(x) get_lowest_set_bit_index (x)
 #define log2_first_set(x)	get_lowest_set_bit_index (x)

 /* Based on "Hacker's Delight" code from GLS. */
 typedef struct
 {
   uword masks[1 + log2_uword_bits];
 } compress_main_t;

 always_inline void
 compress_init (compress_main_t * cm, uword mask)
 {
   uword q, m, zm, n, i;

   m = ~mask;
   zm = mask;

   cm->masks[0] = mask;
   for (i = 0; i < log2_uword_bits; i++)
     {
       q = m;
       m ^= m << 1;
       m ^= m << 2;
       m ^= m << 4;
       m ^= m << 8;
       m ^= m << 16;
 #if uword_bits > 32
       m ^= m << (uword) 32;
 #endif
       cm->masks[1 + i] = n = (m << 1) & zm;
       m = q & ~m;
       q = zm & n;
       zm = zm ^ q ^ (q >> (1 << i));
     }
 }

 always_inline uword
 compress_bits (compress_main_t * cm, uword x)
 {
   uword q, r;

   r = x & cm->masks[0];
   q = r & cm->masks[1];
   r ^= q ^ (q >> 1);
   q = r & cm->masks[2];
   r ^= q ^ (q >> 2);
   q = r & cm->masks[3];
   r ^= q ^ (q >> 4);
   q = r & cm->masks[4];
   r ^= q ^ (q >> 8);
   q = r & cm->masks[5];
   r ^= q ^ (q >> 16);
 #if uword_bits > 32
   q = r & cm->masks[6];
   r ^= q ^ (q >> (uword) 32);
 #endif

   return r;
 }

 always_inline uword
 rotate_left (uword x, uword i)
 {
   return (x << i) | (x >> (BITS (i) - i));
 }

 always_inline uword
 rotate_right (uword x, uword i)
 {
   return (x >> i) | (x << (BITS (i) - i));
 }

 /* Returns snoob from Hacker's Delight.  Next highest number
    with same number of set bits. */
 always_inline uword
 next_with_same_number_of_set_bits (uword x)
 {
   uword smallest, ripple, ones;
   smallest = x & -x;
   ripple = x + smallest;
   ones = x ^ ripple;
   ones = ones >> (2 + log2_first_set (x));
   return ripple | ones;
 }

 #define foreach_set_bit_index(i, v)                                           \
   for (uword _tmp = (v) + 0 * (uword) (i = get_lowest_set_bit_index (v));     \
        _tmp;                                                                  \
        i = get_lowest_set_bit_index (_tmp = clear_lowest_set_bit (_tmp)))

 static_always_inline uword
 uword_bitmap_count_set_bits (uword *bmp, uword n_uwords)
 {
   uword count = 0;
   while (n_uwords--)
     count += count_set_bits (bmp++[0]);
   return count;
 }

 static_always_inline uword
 uword_bitmap_is_bit_set (uword *bmp, uword bit_index)
 {
   bmp += bit_index / uword_bits;
   bit_index %= uword_bits;
   return (bmp[0] >> bit_index) & 1;
 }

 static_always_inline void
 uword_bitmap_set_bits_at_index (uword *bmp, uword bit_index, uword n_bits)
 {
   bmp += bit_index / uword_bits;
   bit_index %= uword_bits;
   uword max_bits = uword_bits - bit_index;

   if (n_bits < max_bits)
     {
       bmp[0] |= pow2_mask (n_bits) << bit_index;
       return;
     }

   bmp++[0] |= pow2_mask (max_bits) << bit_index;
   n_bits -= max_bits;

   for (; n_bits >= uword_bits; bmp++, n_bits -= uword_bits)
     bmp[0] = ~0ULL;

   if (n_bits)
     bmp[0] |= pow2_mask (n_bits);
 }

 static_always_inline void
 uword_bitmap_clear_bits_at_index (uword *bmp, uword bit_index, uword n_bits)
 {
   bmp += bit_index / uword_bits;
   bit_index %= uword_bits;
   uword max_bits = uword_bits - bit_index;

   if (n_bits < max_bits)
     {
       bmp[0] &= ~(pow2_mask (n_bits) << bit_index);
       return;
     }

   bmp++[0] &= ~(pow2_mask (max_bits) << bit_index);
   n_bits -= max_bits;

   for (; n_bits >= uword_bits; bmp++, n_bits -= uword_bits)
     bmp[0] = 0ULL;

   if (n_bits)
     bmp[0] &= ~pow2_mask (n_bits);
 }

 static_always_inline int
 uword_bitmap_find_first_set (uword *bmp)
 {
   uword *b = bmp;
   while (b[0] == 0)
     b++;

   return (b - bmp) * uword_bits + get_lowest_set_bit_index (b[0]);
 }

 static_always_inline u32
 bit_extract_u32 (u32 v, u32 mask)
 {
 #ifdef __BMI2__
   return _pext_u32 (v, mask);
 #else
   u32 rv = 0;
   u32 bit = 1;

   while (mask)
     {
       u32 lowest_mask_bit = get_lowest_set_bit (mask);
       mask ^= lowest_mask_bit;
       rv |= (v & lowest_mask_bit) ? bit : 0;
       bit <<= 1;
     }

   return rv;
 #endif
 }

 static_always_inline u64
 bit_extract_u64 (u64 v, u64 mask)
 {
 #ifdef __BMI2__
   return _pext_u64 (v, mask);
 #else
   u64 rv = 0;
   u64 bit = 1;

   while (mask)
     {
       u64 lowest_mask_bit = get_lowest_set_bit (mask);
       mask ^= lowest_mask_bit;
       rv |= (v & lowest_mask_bit) ? bit : 0;
       bit <<= 1;
     }

   return rv;
 #endif
 }

 static_always_inline void
 u64_bit_set (u64 *p, u8 bit_index, u8 is_one)
 {
   u64 val = *p;
   val &= ~(1ULL << bit_index);
   val |= 1ULL << bit_index;
   *p = val;
 }

 static_always_inline void
 u32_bit_set (u32 *p, u8 bit_index, u8 is_one)
 {
   u32 val = *p;
   val &= ~(1U << bit_index);
   val |= 1U << bit_index;
   *p = val;
 }

 static_always_inline int
 u64_is_bit_set (u64 v, u8 bit_index)
 {
   return (v & 1ULL << bit_index) != 0;
 }

 static_always_inline int
 u32_is_bit_set (u32 v, u8 bit_index)
 {
   return (v & 1U << bit_index) != 0;
 }

 #else
 #warning "already included"
 #endif /* included_clib_bitops_h */

 /*
  * fd.io coding-style-patch-verification: ON
  *
  * Local Variables:
  * eval: (c-set-style "gnu")
  * End:
  */
	/*
	* Copyright (c) 2015 Cisco and/or its affiliates.
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at:
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/
	/*
	Copyright (c) 2005 Eliot Dresselhaus

	Permission is hereby granted, free of charge, to any person obtaining
	a copy of this software and associated documentation files (the
	"Software"), to deal in the Software without restriction, including
	without limitation the rights to use, copy, modify, merge, publish,
	distribute, sublicense, and/or sell copies of the Software, and to
	permit persons to whom the Software is furnished to do so, subject to
	the following conditions:

	The above copyright notice and this permission notice shall be
	included in all copies or substantial portions of the Software.

	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
	EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
	MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
	NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
	LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
	OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
	WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
	*/

	#ifndef included_clib_bitops_h
	#define included_clib_bitops_h

	#define SET_BIT(i) (1 << i)
	#define GET_BIT(n, i) (n >> i) & 1U

	static_always_inline uword
	clear_lowest_set_bit (uword x)
	{
	#ifdef __BMI__
	return uword_bits > 32 ? _blsr_u64 (x) : _blsr_u32 (x);
	#else
	return x & (x - 1);
	#endif
	}

	static_always_inline uword
	get_lowest_set_bit (uword x)
	{
	#ifdef __BMI__
	return uword_bits > 32 ? _blsi_u64 (x) : _blsi_u32 (x);
	#else
	return x & -x;
	#endif
	}

	static_always_inline u8
	get_lowest_set_bit_index (uword x)
	{
	return uword_bits > 32 ? __builtin_ctzll (x) : __builtin_ctz (x);
	}

	/* Population count from Hacker's Delight. */
	always_inline uword
	count_set_bits (uword x)
	{
	#ifdef __POPCNT__
	return uword_bits > 32 ? __builtin_popcountll (x) : __builtin_popcount (x);
	#else
	#if uword_bits == 64
	const uword c1 = 0x5555555555555555;
	const uword c2 = 0x3333333333333333;
	const uword c3 = 0x0f0f0f0f0f0f0f0f;
	#else
	const uword c1 = 0x55555555;
	const uword c2 = 0x33333333;
	const uword c3 = 0x0f0f0f0f;
	#endif

	/* Sum 1 bit at a time. */
	x = x - ((x >> (uword) 1) & c1);

	/* 2 bits at a time. */
	x = (x & c2) + ((x >> (uword) 2) & c2);

	/* 4 bits at a time. */
	x = (x + (x >> (uword) 4)) & c3;

	/* 8, 16, 32 bits at a time. */
	x = x + (x >> (uword) 8);
	x = x + (x >> (uword) 16);
	#if uword_bits == 64
	x = x + (x >> (uword) 32);
	#endif

	return x & (2 * BITS (uword) - 1);
	#endif
	}

	#if uword_bits == 64
	#define count_leading_zeros(x) __builtin_clzll (x)
	#else
	#define count_leading_zeros(x) __builtin_clzll (x)
	#endif

	#define count_trailing_zeros(x) get_lowest_set_bit_index (x)
	#define log2_first_set(x) get_lowest_set_bit_index (x)

	/* Based on "Hacker's Delight" code from GLS. */
	typedef struct
	{
	uword masks[1 + log2_uword_bits];
	} compress_main_t;

	always_inline void
	compress_init (compress_main_t * cm, uword mask)
	{
	uword q, m, zm, n, i;

	m = ~mask;
	zm = mask;

	cm->masks[0] = mask;
	for (i = 0; i < log2_uword_bits; i++)
	{
	q = m;
	m ^= m << 1;
	m ^= m << 2;
	m ^= m << 4;
	m ^= m << 8;
	m ^= m << 16;
	#if uword_bits > 32
	m ^= m << (uword) 32;
	#endif
	cm->masks[1 + i] = n = (m << 1) & zm;
	m = q & ~m;
	q = zm & n;
	zm = zm ^ q ^ (q >> (1 << i));
	}
	}

	always_inline uword
	compress_bits (compress_main_t * cm, uword x)
	{
	uword q, r;

	r = x & cm->masks[0];
	q = r & cm->masks[1];
	r ^= q ^ (q >> 1);
	q = r & cm->masks[2];
	r ^= q ^ (q >> 2);
	q = r & cm->masks[3];
	r ^= q ^ (q >> 4);
	q = r & cm->masks[4];
	r ^= q ^ (q >> 8);
	q = r & cm->masks[5];
	r ^= q ^ (q >> 16);
	#if uword_bits > 32
	q = r & cm->masks[6];
	r ^= q ^ (q >> (uword) 32);
	#endif

	return r;
	}

	always_inline uword
	rotate_left (uword x, uword i)
	{
	return (x << i) \| (x >> (BITS (i) - i));
	}

	always_inline uword
	rotate_right (uword x, uword i)
	{
	return (x >> i) \| (x << (BITS (i) - i));
	}

	/* Returns snoob from Hacker's Delight. Next highest number
	with same number of set bits. */
	always_inline uword
	next_with_same_number_of_set_bits (uword x)
	{
	uword smallest, ripple, ones;
	smallest = x & -x;
	ripple = x + smallest;
	ones = x ^ ripple;
	ones = ones >> (2 + log2_first_set (x));
	return ripple \| ones;
	}

	#define foreach_set_bit_index(i, v) \
	for (uword _tmp = (v) + 0 * (uword) (i = get_lowest_set_bit_index (v)); \
	_tmp; \
	i = get_lowest_set_bit_index (_tmp = clear_lowest_set_bit (_tmp)))

	static_always_inline uword
	uword_bitmap_count_set_bits (uword *bmp, uword n_uwords)
	{
	uword count = 0;
	while (n_uwords--)
	count += count_set_bits (bmp++[0]);
	return count;
	}

	static_always_inline uword
	uword_bitmap_is_bit_set (uword *bmp, uword bit_index)
	{
	bmp += bit_index / uword_bits;
	bit_index %= uword_bits;
	return (bmp[0] >> bit_index) & 1;
	}

	static_always_inline void
	uword_bitmap_set_bits_at_index (uword *bmp, uword bit_index, uword n_bits)
	{
	bmp += bit_index / uword_bits;
	bit_index %= uword_bits;
	uword max_bits = uword_bits - bit_index;

	if (n_bits < max_bits)
	{
	bmp[0] \|= pow2_mask (n_bits) << bit_index;
	return;
	}

	bmp++[0] \|= pow2_mask (max_bits) << bit_index;
	n_bits -= max_bits;

	for (; n_bits >= uword_bits; bmp++, n_bits -= uword_bits)
	bmp[0] = ~0ULL;

	if (n_bits)
	bmp[0] \|= pow2_mask (n_bits);
	}

	static_always_inline void
	uword_bitmap_clear_bits_at_index (uword *bmp, uword bit_index, uword n_bits)
	{
	bmp += bit_index / uword_bits;
	bit_index %= uword_bits;
	uword max_bits = uword_bits - bit_index;

	if (n_bits < max_bits)
	{
	bmp[0] &= ~(pow2_mask (n_bits) << bit_index);
	return;
	}

	bmp++[0] &= ~(pow2_mask (max_bits) << bit_index);
	n_bits -= max_bits;

	for (; n_bits >= uword_bits; bmp++, n_bits -= uword_bits)
	bmp[0] = 0ULL;

	if (n_bits)
	bmp[0] &= ~pow2_mask (n_bits);
	}

	static_always_inline int
	uword_bitmap_find_first_set (uword *bmp)
	{
	uword *b = bmp;
	while (b[0] == 0)
	b++;

	return (b - bmp) * uword_bits + get_lowest_set_bit_index (b[0]);
	}

	static_always_inline u32
	bit_extract_u32 (u32 v, u32 mask)
	{
	#ifdef __BMI2__
	return _pext_u32 (v, mask);
	#else
	u32 rv = 0;
	u32 bit = 1;

	while (mask)
	{
	u32 lowest_mask_bit = get_lowest_set_bit (mask);
	mask ^= lowest_mask_bit;
	rv \|= (v & lowest_mask_bit) ? bit : 0;
	bit <<= 1;
	}

	return rv;
	#endif
	}

	static_always_inline u64
	bit_extract_u64 (u64 v, u64 mask)
	{
	#ifdef __BMI2__
	return _pext_u64 (v, mask);
	#else
	u64 rv = 0;
	u64 bit = 1;

	while (mask)
	{
	u64 lowest_mask_bit = get_lowest_set_bit (mask);
	mask ^= lowest_mask_bit;
	rv \|= (v & lowest_mask_bit) ? bit : 0;
	bit <<= 1;
	}

	return rv;
	#endif
	}

	static_always_inline void
	u64_bit_set (u64 *p, u8 bit_index, u8 is_one)
	{
	u64 val = *p;
	val &= ~(1ULL << bit_index);
	val \|= 1ULL << bit_index;
	*p = val;
	}

	static_always_inline void
	u32_bit_set (u32 *p, u8 bit_index, u8 is_one)
	{
	u32 val = *p;
	val &= ~(1U << bit_index);
	val \|= 1U << bit_index;
	*p = val;
	}

	static_always_inline int
	u64_is_bit_set (u64 v, u8 bit_index)
	{
	return (v & 1ULL << bit_index) != 0;
	}

	static_always_inline int
	u32_is_bit_set (u32 v, u8 bit_index)
	{
	return (v & 1U << bit_index) != 0;
	}

	#else
	#warning "already included"
	#endif /* included_clib_bitops_h */

	/*
	* fd.io coding-style-patch-verification: ON
	*
	* Local Variables:
	* eval: (c-set-style "gnu")
	* End:
	*/