1$NetBSD: timesoftfloat.txt,v 1.1 2000/06/06 08:15:11 bjh21 Exp $ 2$FreeBSD$ 3 4Documentation for the `timesoftfloat' Program of SoftFloat Release 2a 5 6John R. Hauser 71998 December 14 8 9 10------------------------------------------------------------------------------- 11Introduction 12 13The `timesoftfloat' program evaluates the speed of SoftFloat's floating- 14point routines. Each routine can be evaluated for every relevant rounding 15mode, tininess mode, and/or rounding precision. 16 17 18------------------------------------------------------------------------------- 19Contents 20 21 Introduction 22 Contents 23 Legal Notice 24 Executing `timesoftfloat' 25 Options 26 -help 27 -precision32, -precision64, -precision80 28 -nearesteven, -tozero, -down, -up 29 -tininessbefore, -tininessafter 30 Function Sets 31 32 33 34------------------------------------------------------------------------------- 35Legal Notice 36 37The `timesoftfloat' program was written by John R. Hauser. 38 39THIS SOFTWARE IS DISTRIBUTED AS IS, FOR FREE. Although reasonable effort 40has been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT 41TIMES RESULT IN INCORRECT BEHAVIOR. USE OF THIS SOFTWARE IS RESTRICTED TO 42PERSONS AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ANY 43AND ALL LOSSES, COSTS, OR OTHER PROBLEMS ARISING FROM ITS USE. 44 45 46------------------------------------------------------------------------------- 47Executing `timesoftfloat' 48 49The `timesoftfloat' program is intended to be invoked from a command line 50interpreter as follows: 51 52 timesoftfloat [<option>...] <function> 53 54Here square brackets ([]) indicate optional items, while angled brackets 55(<>) denote parameters to be filled in. The `<function>' argument is 56the name of the SoftFloat routine to evaluate, such as `float32_add' or 57`float64_to_int32'. The allowed options are detailed in the next section, 58_Options_. If `timesoftfloat' is executed without any arguments, a summary 59of usage is written. It is also possible to evaluate all machine functions 60in a single invocation as explained in the section _Function_Sets_ later in 61this document. 62 63Ordinarily, a function's speed will be evaulated separately for each of 64the four rounding modes, one after the other. If the rounding mode is not 65supposed to have any affect on the results of a function--for instance, 66some operations do not require rounding--only the nearest/even rounding mode 67is timed. In the same way, if a function is affected by the way in which 68underflow tininess is detected, `timesoftfloat' times the function both with 69tininess detected before rounding and after rounding. For extended double- 70precision operations affected by rounding precision control, `timesoftfloat' 71also times the function for all three rounding precision modes, one after 72the other. Evaluation of a function can be limited to a single rounding 73mode, a single tininess mode, and/or a single rounding precision with 74appropriate options (see _Options_). 75 76For each function and mode evaluated, `timesoftfloat' reports the speed of 77the function in kops/s, or ``thousands of operations per second''. This 78unit of measure differs from the traditional MFLOPS (``millions of floating- 79point operations per second'') only in being a factor of 1000 smaller. 80(1000 kops/s is exactly 1 MFLOPS.) Speeds are reported in thousands instead 81of millions because software floating-point often executes at less than 821 MFLOPS. 83 84The speeds reported by `timesoftfloat' may be affected somewhat by other 85programs executing at the same time as `timesoftfloat'. 86 87Note that the remainder operations (`float32_rem', `float64_rem', 88`floatx80_rem' and `float128_rem') will be markedly slower than other 89operations, particularly for extended double precision (`floatx80') and 90quadruple precision (`float128'). This is inherent to the remainder 91function itself and is not a failing of the SoftFloat implementation. 92 93 94------------------------------------------------------------------------------- 95Options 96 97The `timesoftfloat' program accepts several command options. If mutually 98contradictory options are given, the last one has priority. 99 100- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 101-help 102 103The `-help' option causes a summary of program usage to be written, after 104which the program exits. 105 106- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 107-precision32, -precision64, -precision80 108 109For extended double-precision functions affected by rounding precision 110control, the `-precision32' option restricts evaluation to only the cases 111in which rounding precision is equivalent to single precision. The other 112rounding precision options are not timed. Likewise, the `-precision64' 113and `-precision80' options fix the rounding precision equivalent to double 114precision or extended double precision, respectively. These options are 115ignored for functions not affected by rounding precision control. 116 117- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 118-nearesteven, -tozero, -down, -up 119 120The `-nearesteven' option restricts evaluation to only the cases in which 121the rounding mode is nearest/even. The other rounding mode options are not 122timed. Likewise, `-tozero' forces rounding to zero; `-down' forces rounding 123down; and `-up' forces rounding up. These options are ignored for functions 124that are exact and thus do not round. 125 126- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 127-tininessbefore, -tininessafter 128 129The `-tininessbefore' option restricts evaluation to only the cases 130detecting underflow tininess before rounding. Tininess after rounding 131is not timed. Likewise, `-tininessafter' forces underflow tininess to be 132detected after rounding only. These options are ignored for functions not 133affected by the way in which underflow tininess is detected. 134 135- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 136 137 138------------------------------------------------------------------------------- 139Function Sets 140 141Just as `timesoftfloat' can test an operation for all four rounding modes in 142sequence, multiple operations can also be tested with a single invocation. 143Three sets are recognized: `-all1', `-all2', and `-all'. The set `-all1' 144comprises all one-operand functions; `-all2' is all two-operand functions; 145and `-all' is all functions. A function set can be used in place of a 146function name in the command line, as in 147 148 timesoftfloat [<option>...] -all 149 150 151