-/**
- * This module contains a collection of bit-level operations.
- *
- * Copyright: Copyright (c) 2005-2008, The D Runtime Project
- * License: BSD Style, see LICENSE
- * Authors: Walter Bright, Don Clugston, Sean Kelly
- */
-module bitmanip;
-
-
-version( DDoc )
-{
- /**
- * Scans the bits in v starting with bit 0, looking
- * for the first set bit.
- * Returns:
- * The bit number of the first bit set.
- * The return value is undefined if v is zero.
- */
- int bsf( uint v );
-
-
- /**
- * Scans the bits in v from the most significant bit
- * to the least significant bit, looking
- * for the first set bit.
- * Returns:
- * The bit number of the first bit set.
- * The return value is undefined if v is zero.
- * Example:
- * ---
- * import bitmanip;
- *
- * int main()
- * {
- * uint v;
- * int x;
- *
- * v = 0x21;
- * x = bsf(v);
- * printf("bsf(x%x) = %d\n", v, x);
- * x = bsr(v);
- * printf("bsr(x%x) = %d\n", v, x);
- * return 0;
- * }
- * ---
- * Output:
- * bsf(x21) = 0<br>
- * bsr(x21) = 5
- */
- int bsr( uint v );
-
-
- /**
- * Tests the bit.
- */
- int bt( uint* p, uint bitnum );
-
-
- /**
- * Tests and complements the bit.
- */
- int btc( uint* p, uint bitnum );
-
-
- /**
- * Tests and resets (sets to 0) the bit.
- */
- int btr( uint* p, uint bitnum );
-
-
- /**
- * Tests and sets the bit.
- * Params:
- * p = a non-NULL pointer to an array of uints.
- * index = a bit number, starting with bit 0 of p[0],
- * and progressing. It addresses bits like the expression:
- ---
- p[index / (uint.sizeof*8)] & (1 << (index & ((uint.sizeof*8) - 1)))
- ---
- * Returns:
- * A non-zero value if the bit was set, and a zero
- * if it was clear.
- *
- * Example:
- * ---
- import bitmanip;
-
- int main()
- {
- uint array[2];
-
- array[0] = 2;
- array[1] = 0x100;
-
- printf("btc(array, 35) = %d\n", <b>btc</b>(array, 35));
- printf("array = [0]:x%x, [1]:x%x\n", array[0], array[1]);
-
- printf("btc(array, 35) = %d\n", <b>btc</b>(array, 35));
- printf("array = [0]:x%x, [1]:x%x\n", array[0], array[1]);
-
- printf("bts(array, 35) = %d\n", <b>bts</b>(array, 35));
- printf("array = [0]:x%x, [1]:x%x\n", array[0], array[1]);
-
- printf("btr(array, 35) = %d\n", <b>btr</b>(array, 35));
- printf("array = [0]:x%x, [1]:x%x\n", array[0], array[1]);
-
- printf("bt(array, 1) = %d\n", <b>bt</b>(array, 1));
- printf("array = [0]:x%x, [1]:x%x\n", array[0], array[1]);
-
- return 0;
- }
- * ---
- * Output:
- <pre>
- btc(array, 35) = 0
- array = [0]:x2, [1]:x108
- btc(array, 35) = -1
- array = [0]:x2, [1]:x100
- bts(array, 35) = 0
- array = [0]:x2, [1]:x108
- btr(array, 35) = -1
- array = [0]:x2, [1]:x100
- bt(array, 1) = -1
- array = [0]:x2, [1]:x100
- </pre>
- */
- int bts( uint* p, uint bitnum );
-
-
- /**
- * Swaps bytes in a 4 byte uint end-to-end, i.e. byte 0 becomes
- * byte 3, byte 1 becomes byte 2, byte 2 becomes byte 1, byte 3
- * becomes byte 0.
- */
- uint bswap( uint v );
-
-
- /**
- * Reads I/O port at port_address.
- */
- ubyte inp( uint port_address );
-
-
- /**
- * ditto
- */
- ushort inpw( uint port_address );
-
-
- /**
- * ditto
- */
- uint inpl( uint port_address );
-
-
- /**
- * Writes and returns value to I/O port at port_address.
- */
- ubyte outp( uint port_address, ubyte value );
-
-
- /**
- * ditto
- */
- ushort outpw( uint port_address, ushort value );
-
-
- /**
- * ditto
- */
- uint outpl( uint port_address, uint value );
-}
-else
-{
- public import std.intrinsic;
-}
-
-
-/**
- * Calculates the number of set bits in a 32-bit integer.
- */
-int popcnt( uint x )
-{
- // Avoid branches, and the potential for cache misses which
- // could be incurred with a table lookup.
-
- // We need to mask alternate bits to prevent the
- // sum from overflowing.
- // add neighbouring bits. Each bit is 0 or 1.
- x = x - ((x>>1) & 0x5555_5555);
- // now each two bits of x is a number 00,01 or 10.
- // now add neighbouring pairs
- x = ((x&0xCCCC_CCCC)>>2) + (x&0x3333_3333);
- // now each nibble holds 0000-0100. Adding them won't
- // overflow any more, so we don't need to mask any more
-
- // Now add the nibbles, then the bytes, then the words
- // We still need to mask to prevent double-counting.
- // Note that if we used a rotate instead of a shift, we
- // wouldn't need the masks, and could just divide the sum
- // by 8 to account for the double-counting.
- // On some CPUs, it may be faster to perform a multiply.
-
- x += (x>>4);
- x &= 0x0F0F_0F0F;
- x += (x>>8);
- x &= 0x00FF_00FF;
- x += (x>>16);
- x &= 0xFFFF;
- return x;
-}
-
-
-/**
- * Reverses the order of bits in a 32-bit integer.
- */
-uint bitswap( uint x )
-{
-
- version( D_InlineAsm_X86 )
- {
- asm
- {
- // Author: Tiago Gasiba.
- mov EDX, EAX;
- shr EAX, 1;
- and EDX, 0x5555_5555;
- and EAX, 0x5555_5555;
- shl EDX, 1;
- or EAX, EDX;
- mov EDX, EAX;
- shr EAX, 2;
- and EDX, 0x3333_3333;
- and EAX, 0x3333_3333;
- shl EDX, 2;
- or EAX, EDX;
- mov EDX, EAX;
- shr EAX, 4;
- and EDX, 0x0f0f_0f0f;
- and EAX, 0x0f0f_0f0f;
- shl EDX, 4;
- or EAX, EDX;
- bswap EAX;
- }
- }
- else
- {
- // swap odd and even bits
- x = ((x >> 1) & 0x5555_5555) | ((x & 0x5555_5555) << 1);
- // swap consecutive pairs
- x = ((x >> 2) & 0x3333_3333) | ((x & 0x3333_3333) << 2);
- // swap nibbles
- x = ((x >> 4) & 0x0F0F_0F0F) | ((x & 0x0F0F_0F0F) << 4);
- // swap bytes
- x = ((x >> 8) & 0x00FF_00FF) | ((x & 0x00FF_00FF) << 8);
- // swap 2-byte long pairs
- x = ( x >> 16 ) | ( x << 16);
- return x;
-
- }
-}
+/**\r
+ * This module contains a collection of bit-level operations.\r
+ *\r
+ * Copyright: Copyright (c) 2005-2008, The D Runtime Project\r
+ * License: BSD Style, see LICENSE\r
+ * Authors: Walter Bright, Don Clugston, Sean Kelly\r
+ */\r
+module bitmanip;\r
+\r
+\r
+version( DDoc )\r
+{\r
+ /**\r
+ * Scans the bits in v starting with bit 0, looking\r
+ * for the first set bit.\r
+ * Returns:\r
+ * The bit number of the first bit set.\r
+ * The return value is undefined if v is zero.\r
+ */\r
+ int bsf( uint v );\r
+\r
+\r
+ /**\r
+ * Scans the bits in v from the most significant bit\r
+ * to the least significant bit, looking\r
+ * for the first set bit.\r
+ * Returns:\r
+ * The bit number of the first bit set.\r
+ * The return value is undefined if v is zero.\r
+ * Example:\r
+ * ---\r
+ * import bitmanip;\r
+ *\r
+ * int main()\r
+ * {\r
+ * uint v;\r
+ * int x;\r
+ *\r
+ * v = 0x21;\r
+ * x = bsf(v);\r
+ * printf("bsf(x%x) = %d\n", v, x);\r
+ * x = bsr(v);\r
+ * printf("bsr(x%x) = %d\n", v, x);\r
+ * return 0;\r
+ * }\r
+ * ---\r
+ * Output:\r
+ * bsf(x21) = 0<br>\r
+ * bsr(x21) = 5\r
+ */\r
+ int bsr( uint v );\r
+\r
+\r
+ /**\r
+ * Tests the bit.\r
+ */\r
+ int bt( uint* p, uint bitnum );\r
+\r
+\r
+ /**\r
+ * Tests and complements the bit.\r
+ */\r
+ int btc( uint* p, uint bitnum );\r
+\r
+\r
+ /**\r
+ * Tests and resets (sets to 0) the bit.\r
+ */\r
+ int btr( uint* p, uint bitnum );\r
+\r
+\r
+ /**\r
+ * Tests and sets the bit.\r
+ * Params:\r
+ * p = a non-NULL pointer to an array of uints.\r
+ * index = a bit number, starting with bit 0 of p[0],\r
+ * and progressing. It addresses bits like the expression:\r
+ ---\r
+ p[index / (uint.sizeof*8)] & (1 << (index & ((uint.sizeof*8) - 1)))\r
+ ---\r
+ * Returns:\r
+ * A non-zero value if the bit was set, and a zero\r
+ * if it was clear.\r
+ *\r
+ * Example:\r
+ * ---\r
+ import bitmanip;\r
+\r
+ int main()\r
+ {\r
+ uint array[2];\r
+\r
+ array[0] = 2;\r
+ array[1] = 0x100;\r
+\r
+ printf("btc(array, 35) = %d\n", <b>btc</b>(array, 35));\r
+ printf("array = [0]:x%x, [1]:x%x\n", array[0], array[1]);\r
+\r
+ printf("btc(array, 35) = %d\n", <b>btc</b>(array, 35));\r
+ printf("array = [0]:x%x, [1]:x%x\n", array[0], array[1]);\r
+\r
+ printf("bts(array, 35) = %d\n", <b>bts</b>(array, 35));\r
+ printf("array = [0]:x%x, [1]:x%x\n", array[0], array[1]);\r
+\r
+ printf("btr(array, 35) = %d\n", <b>btr</b>(array, 35));\r
+ printf("array = [0]:x%x, [1]:x%x\n", array[0], array[1]);\r
+\r
+ printf("bt(array, 1) = %d\n", <b>bt</b>(array, 1));\r
+ printf("array = [0]:x%x, [1]:x%x\n", array[0], array[1]);\r
+\r
+ return 0;\r
+ }\r
+ * ---\r
+ * Output:\r
+ <pre>\r
+ btc(array, 35) = 0\r
+ array = [0]:x2, [1]:x108\r
+ btc(array, 35) = -1\r
+ array = [0]:x2, [1]:x100\r
+ bts(array, 35) = 0\r
+ array = [0]:x2, [1]:x108\r
+ btr(array, 35) = -1\r
+ array = [0]:x2, [1]:x100\r
+ bt(array, 1) = -1\r
+ array = [0]:x2, [1]:x100\r
+ </pre>\r
+ */\r
+ int bts( uint* p, uint bitnum );\r
+\r
+\r
+ /**\r
+ * Swaps bytes in a 4 byte uint end-to-end, i.e. byte 0 becomes\r
+ * byte 3, byte 1 becomes byte 2, byte 2 becomes byte 1, byte 3\r
+ * becomes byte 0.\r
+ */\r
+ uint bswap( uint v );\r
+\r
+\r
+ /**\r
+ * Reads I/O port at port_address.\r
+ */\r
+ ubyte inp( uint port_address );\r
+\r
+\r
+ /**\r
+ * ditto\r
+ */\r
+ ushort inpw( uint port_address );\r
+\r
+\r
+ /**\r
+ * ditto\r
+ */\r
+ uint inpl( uint port_address );\r
+\r
+\r
+ /**\r
+ * Writes and returns value to I/O port at port_address.\r
+ */\r
+ ubyte outp( uint port_address, ubyte value );\r
+\r
+\r
+ /**\r
+ * ditto\r
+ */\r
+ ushort outpw( uint port_address, ushort value );\r
+\r
+\r
+ /**\r
+ * ditto\r
+ */\r
+ uint outpl( uint port_address, uint value );\r
+}\r
+else\r
+{\r
+ public import std.intrinsic;\r
+}\r
+\r
+\r
+/**\r
+ * Calculates the number of set bits in a 32-bit integer.\r
+ */\r
+int popcnt( uint x )\r
+{\r
+ // Avoid branches, and the potential for cache misses which\r
+ // could be incurred with a table lookup.\r
+\r
+ // We need to mask alternate bits to prevent the\r
+ // sum from overflowing.\r
+ // add neighbouring bits. Each bit is 0 or 1.\r
+ x = x - ((x>>1) & 0x5555_5555);\r
+ // now each two bits of x is a number 00,01 or 10.\r
+ // now add neighbouring pairs\r
+ x = ((x&0xCCCC_CCCC)>>2) + (x&0x3333_3333);\r
+ // now each nibble holds 0000-0100. Adding them won't\r
+ // overflow any more, so we don't need to mask any more\r
+\r
+ // Now add the nibbles, then the bytes, then the words\r
+ // We still need to mask to prevent double-counting.\r
+ // Note that if we used a rotate instead of a shift, we\r
+ // wouldn't need the masks, and could just divide the sum\r
+ // by 8 to account for the double-counting.\r
+ // On some CPUs, it may be faster to perform a multiply.\r
+\r
+ x += (x>>4);\r
+ x &= 0x0F0F_0F0F;\r
+ x += (x>>8);\r
+ x &= 0x00FF_00FF;\r
+ x += (x>>16);\r
+ x &= 0xFFFF;\r
+ return x;\r
+}\r
+\r
+\r
+/**\r
+ * Reverses the order of bits in a 32-bit integer.\r
+ */\r
+uint bitswap( uint x )\r
+{\r
+\r
+ version( D_InlineAsm_X86 )\r
+ {\r
+ asm\r
+ {\r
+ // Author: Tiago Gasiba.\r
+ mov EDX, EAX;\r
+ shr EAX, 1;\r
+ and EDX, 0x5555_5555;\r
+ and EAX, 0x5555_5555;\r
+ shl EDX, 1;\r
+ or EAX, EDX;\r
+ mov EDX, EAX;\r
+ shr EAX, 2;\r
+ and EDX, 0x3333_3333;\r
+ and EAX, 0x3333_3333;\r
+ shl EDX, 2;\r
+ or EAX, EDX;\r
+ mov EDX, EAX;\r
+ shr EAX, 4;\r
+ and EDX, 0x0f0f_0f0f;\r
+ and EAX, 0x0f0f_0f0f;\r
+ shl EDX, 4;\r
+ or EAX, EDX;\r
+ bswap EAX;\r
+ }\r
+ }\r
+ else\r
+ {\r
+ // swap odd and even bits\r
+ x = ((x >> 1) & 0x5555_5555) | ((x & 0x5555_5555) << 1);\r
+ // swap consecutive pairs\r
+ x = ((x >> 2) & 0x3333_3333) | ((x & 0x3333_3333) << 2);\r
+ // swap nibbles\r
+ x = ((x >> 4) & 0x0F0F_0F0F) | ((x & 0x0F0F_0F0F) << 4);\r
+ // swap bytes\r
+ x = ((x >> 8) & 0x00FF_00FF) | ((x & 0x00FF_00FF) << 8);\r
+ // swap 2-byte long pairs\r
+ x = ( x >> 16 ) | ( x << 16);\r
+ return x;\r
+\r
+ }\r
+}\r
projects / software / druntime.git / commitdiff