Mercurial > projects > ldc
view tango/std/intrinsic.di @ 135:176bd52b3cf5 trunk
[svn r139] Fixed bug #33, thanks for the report :)
author | lindquist |
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date | Mon, 14 Jan 2008 23:09:55 +0100 |
parents | 1700239cab2e |
children | f5ca6bbbf1d7 |
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/** * These functions are built-in intrinsics to the compiler. * * Intrinsic functions are functions built in to the compiler, usually to take * advantage of specific CPU features that are inefficient to handle via * external functions. The compiler's optimizer and code generator are fully * integrated in with intrinsic functions, bringing to bear their full power on * them. This can result in some surprising speedups. * * Copyright: Public Domain * License: Public Domain * Authors: Walter Bright */ module std.intrinsic; /** * 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 std.intrinsic; * * 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 std.intrinsic; 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 );