projects / ceph.git / blame
| Commit | Line | Data |
|---|---|---|
| 7c673cae FG |
1 | <html> |
| 2 | <head> | |
| 3 | <title>BOOST_PP_MUL_D</title> | |
| 4 | <link rel="stylesheet" type="text/css" href="../styles.css"> | |
| 5 | </head> | |
| 6 | <body> | |
| 7 | <div style="margin-left: 0px;"> | |
| 8 | The <b>BOOST_PP_MUL_D</b> macro expands to the product of its second and third arguments. | |
| 9 | It reenters <b>BOOST_PP_WHILE</b> with maximum efficiency. | |
| 10 | </div> | |
| 11 | <h4>Usage</h4> | |
| 12 | <div class="code"> | |
| 13 | <b>BOOST_PP_MUL_D</b>(<i>d</i>, <i>x</i>, <i>y</i>) | |
| 14 | </div> | |
| 15 | <h4>Arguments</h4> | |
| 16 | <dl> | |
| 17 | <dt>d</dt> | |
| 18 | <dd> | |
| 19 | The next available <b>BOOST_PP_WHILE</b> iteration. | |
| 20 | </dd> | |
| 21 | <dt>x</dt> | |
| 22 | <dd> | |
| 23 | The multiplicand of the operation. | |
| 24 | Valid values range from <i>0</i> to <b>BOOST_PP_LIMIT_MAG</b>. | |
| 25 | </dd> | |
| 26 | <dt>y</dt> | |
| 27 | <dd> | |
| 28 | The multiplier of the operation. | |
| 29 | Valid values range from <i>0</i> to <b>BOOST_PP_LIMIT_MAG</b>. | |
| 30 | </dd> | |
| 31 | </dl> | |
| 32 | <h4>Remarks</h4> | |
| 33 | <div> | |
| 34 | If the product of <i>x</i> and <i>y</i> is greater than <b>BOOST_PP_LIMIT_MAG</b>, the result is saturated to <b>BOOST_PP_LIMIT_MAG</b>. | |
| 35 | </div> | |
| 36 | <div> | |
| 37 | This macro is the most efficient when <i>x</i> is greater than or equal to <i>y</i>. | |
| 38 | However, the efficiency gain is not worth actually comparing the two arguments prior to invocation. | |
| 39 | In other words, <i>x</i> should be the value that is <i>most likely</i> to be the largest of the two operands. | |
| 40 | </div> | |
| 41 | <h4>See Also</h4> | |
| 42 | <ul> | |
| 43 | <li><a href="limit_mag.html">BOOST_PP_LIMIT_MAG</a></li> | |
| 44 | <li><a href="mul.html">BOOST_PP_MUL</a></li> | |
| 45 | </ul> | |
| 46 | <h4>Requirements</h4> | |
| 47 | <div> | |
| 48 | <b>Header:</b> <a href="../headers/arithmetic/mul.html"><boost/preprocessor/arithmetic/mul.hpp></a> | |
| 49 | </div> | |
| 50 | <h4>Sample Code</h4> | |
| 51 | <div><pre> | |
| 52 | #include <<a href="../headers/arithmetic/dec.html">boost/preprocessor/arithmetic/dec.hpp</a>> | |
| 53 | #include <<a href="../headers/arithmetic/mul.html">boost/preprocessor/arithmetic/mul.hpp</a>> | |
| 54 | #include <<a href="../headers/control/while.html">boost/preprocessor/control/while.hpp</a>> | |
| 55 | #include <<a href="../headers/tuple/elem.html">boost/preprocessor/tuple/elem.hpp</a>> | |
| 56 | ||
| 57 | #define PRED(d, data) <a href="tuple_elem.html">BOOST_PP_TUPLE_ELEM</a>(3, 0, data) | |
| 58 | ||
| 59 | #define OP(d, data) \ | |
| 60 | ( \ | |
| 61 | <a href="dec.html">BOOST_PP_DEC</a>( \ | |
| 62 | <a href="tuple_elem.html">BOOST_PP_TUPLE_ELEM</a>(3, 0, data) \ | |
| 63 | ), \ | |
| 64 | <a href="tuple_elem.html">BOOST_PP_TUPLE_ELEM</a>(3, 1, data), \ | |
| 65 | <a href="mul_d.html">BOOST_PP_MUL_D</a>( \ | |
| 66 | d, \ | |
| 67 | <a href="tuple_elem.html">BOOST_PP_TUPLE_ELEM</a>(3, 2, data), \ | |
| 68 | <a href="tuple_elem.html">BOOST_PP_TUPLE_ELEM</a>(3, 1, data) \ | |
| 69 | ) \ | |
| 70 | ) \ | |
| 71 | /**/ | |
| 72 | ||
| 73 | // raise 'x' to the 'n'-th power | |
| 74 | #define EXP(x, n) <a href="tuple_elem.html">BOOST_PP_TUPLE_ELEM</a>(3, 2, <a href="while.html">BOOST_PP_WHILE</a>(PRED, OP, (n, x, 1))) | |
| 75 | ||
| 76 | EXP(4, 2) // expands to 16 | |
| 77 | EXP(2, 3) // expands to 8 | |
| 78 | </pre></div> | |
| 79 | <hr size="1"> | |
| 80 | <div style="margin-left: 0px;"> | |
| 81 |