1 $NetBSD: timesoftfloat.txt,v 1.1 2000/06/06 08:15:11 bjh21 Exp $ 2 3 Documentation for the `timesoftfloat' Program of SoftFloat Release 2a 4 5 John R. Hauser 6 1998 December 14 7 8 9 ------------------------------------------------------------------------------- 10 Introduction 11 12 The `timesoftfloat' program evaluates the speed of SoftFloat's floating- 13 point routines. Each routine can be evaluated for every relevant rounding 14 mode, tininess mode, and/or rounding precision. 15 16 17 ------------------------------------------------------------------------------- 18 Contents 19 20 Introduction 21 Contents 22 Legal Notice 23 Executing `timesoftfloat' 24 Options 25 -help 26 -precision32, -precision64, -precision80 27 -nearesteven, -tozero, -down, -up 28 -tininessbefore, -tininessafter 29 Function Sets 30 31 32 33 ------------------------------------------------------------------------------- 34 Legal Notice 35 36 The `timesoftfloat' program was written by John R. Hauser. 37 38 THIS SOFTWARE IS DISTRIBUTED AS IS, FOR FREE. Although reasonable effort 39 has been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT 40 TIMES RESULT IN INCORRECT BEHAVIOR. USE OF THIS SOFTWARE IS RESTRICTED TO 41 PERSONS AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ANY 42 AND ALL LOSSES, COSTS, OR OTHER PROBLEMS ARISING FROM ITS USE. 43 44 45 ------------------------------------------------------------------------------- 46 Executing `timesoftfloat' 47 48 The `timesoftfloat' program is intended to be invoked from a command line 49 interpreter as follows: 50 51 timesoftfloat [<option>...] <function> 52 53 Here square brackets ([]) indicate optional items, while angled brackets 54 (<>) denote parameters to be filled in. The `<function>' argument is 55 the name of the SoftFloat routine to evaluate, such as `float32_add' or 56 `float64_to_int32'. The allowed options are detailed in the next section, 57 _Options_. If `timesoftfloat' is executed without any arguments, a summary 58 of usage is written. It is also possible to evaluate all machine functions 59 in a single invocation as explained in the section _Function_Sets_ later in 60 this document. 61 62 Ordinarily, a function's speed will be evaulated separately for each of 63 the four rounding modes, one after the other. If the rounding mode is not 64 supposed to have any affect on the results of a function--for instance, 65 some operations do not require rounding--only the nearest/even rounding mode 66 is timed. In the same way, if a function is affected by the way in which 67 underflow tininess is detected, `timesoftfloat' times the function both with 68 tininess detected before rounding and after rounding. For extended double- 69 precision operations affected by rounding precision control, `timesoftfloat' 70 also times the function for all three rounding precision modes, one after 71 the other. Evaluation of a function can be limited to a single rounding 72 mode, a single tininess mode, and/or a single rounding precision with 73 appropriate options (see _Options_). 74 75 For each function and mode evaluated, `timesoftfloat' reports the speed of 76 the function in kops/s, or ``thousands of operations per second''. This 77 unit of measure differs from the traditional MFLOPS (``millions of floating- 78 point operations per second'') only in being a factor of 1000 smaller. 79 (1000 kops/s is exactly 1 MFLOPS.) Speeds are reported in thousands instead 80 of millions because software floating-point often executes at less than 81 1 MFLOPS. 82 83 The speeds reported by `timesoftfloat' may be affected somewhat by other 84 programs executing at the same time as `timesoftfloat'. 85 86 Note that the remainder operations (`float32_rem', `float64_rem', 87 `floatx80_rem' and `float128_rem') will be markedly slower than other 88 operations, particularly for extended double precision (`floatx80') and 89 quadruple precision (`float128'). This is inherent to the remainder 90 function itself and is not a failing of the SoftFloat implementation. 91 92 93 ------------------------------------------------------------------------------- 94 Options 95 96 The `timesoftfloat' program accepts several command options. If mutually 97 contradictory options are given, the last one has priority. 98 99 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 100 -help 101 102 The `-help' option causes a summary of program usage to be written, after 103 which the program exits. 104 105 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 106 -precision32, -precision64, -precision80 107 108 For extended double-precision functions affected by rounding precision 109 control, the `-precision32' option restricts evaluation to only the cases 110 in which rounding precision is equivalent to single precision. The other 111 rounding precision options are not timed. Likewise, the `-precision64' 112 and `-precision80' options fix the rounding precision equivalent to double 113 precision or extended double precision, respectively. These options are 114 ignored for functions not affected by rounding precision control. 115 116 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 117 -nearesteven, -tozero, -down, -up 118 119 The `-nearesteven' option restricts evaluation to only the cases in which 120 the rounding mode is nearest/even. The other rounding mode options are not 121 timed. Likewise, `-tozero' forces rounding to zero; `-down' forces rounding 122 down; and `-up' forces rounding up. These options are ignored for functions 123 that are exact and thus do not round. 124 125 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 126 -tininessbefore, -tininessafter 127 128 The `-tininessbefore' option restricts evaluation to only the cases 129 detecting underflow tininess before rounding. Tininess after rounding 130 is not timed. Likewise, `-tininessafter' forces underflow tininess to be 131 detected after rounding only. These options are ignored for functions not 132 affected by the way in which underflow tininess is detected. 133 134 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 135 136 137 ------------------------------------------------------------------------------- 138 Function Sets 139 140 Just as `timesoftfloat' can test an operation for all four rounding modes in 141 sequence, multiple operations can also be tested with a single invocation. 142 Three sets are recognized: `-all1', `-all2', and `-all'. The set `-all1' 143 comprises all one-operand functions; `-all2' is all two-operand functions; 144 and `-all' is all functions. A function set can be used in place of a 145 function name in the command line, as in 146 147 timesoftfloat [<option>...] -all 148 149 150
