Modules/fpectlmodule.c

   1 /*
   2      ---------------------------------------------------------------------
   3     /                       Copyright (c) 1996.                           \
   4    |          The Regents of the University of California.                 |
   5    |                        All rights reserved.                           |
   6    |                                                                       |
   7    |   Permission to use, copy, modify, and distribute this software for   |
   8    |   any purpose without fee is hereby granted, provided that this en-   |
   9    |   tire notice is included in all copies of any software which is or   |
  10    |   includes  a  copy  or  modification  of  this software and in all   |
  11    |   copies of the supporting documentation for such software.           |
  12    |                                                                       |
  13    |   This  work was produced at the University of California, Lawrence   |
  14    |   Livermore National Laboratory under  contract  no.  W-7405-ENG-48   |
  15    |   between  the  U.S.  Department  of  Energy and The Regents of the   |
  16    |   University of California for the operation of UC LLNL.              |
  17    |                                                                       |
  18    |                              DISCLAIMER                               |
  19    |                                                                       |
  20    |   This  software was prepared as an account of work sponsored by an   |
  21    |   agency of the United States Government. Neither the United States   |
  22    |   Government  nor the University of California nor any of their em-   |
  23    |   ployees, makes any warranty, express or implied, or  assumes  any   |
  24    |   liability  or  responsibility  for the accuracy, completeness, or   |
  25    |   usefulness of any information,  apparatus,  product,  or  process   |
  26    |   disclosed,   or  represents  that  its  use  would  not  infringe   |
  27    |   privately-owned rights. Reference herein to any specific  commer-   |
  28    |   cial  products,  process,  or  service  by trade name, trademark,   |
  29    |   manufacturer, or otherwise, does not  necessarily  constitute  or   |
  30    |   imply  its endorsement, recommendation, or favoring by the United   |
  31    |   States Government or the University of California. The views  and   |
  32    |   opinions  of authors expressed herein do not necessarily state or   |
  33    |   reflect those of the United States Government or  the  University   |
  34    |   of  California,  and shall not be used for advertising or product   |
  35     \  endorsement purposes.                                              /
  36      ---------------------------------------------------------------------
  37 */
  38
  39 /*
  40                   Floating point exception control module.
  41
  42    This Python module provides bare-bones control over floating point
  43    units from several hardware manufacturers.  Specifically, it allows
  44    the user to turn on the generation of SIGFPE whenever any of the
  45    three serious IEEE 754 exceptions (Division by Zero, Overflow,
  46    Invalid Operation) occurs.  We currently ignore Underflow and
  47    Inexact Result exceptions, although those could certainly be added
  48    if desired.
  49
  50    The module also establishes a signal handler for SIGFPE during
  51    initialization.  This builds on code found in the Python
  52    distribution at Include/pyfpe.h and Python/pyfpe.c.  If those files
  53    are not in your Python distribution, find them in a patch at
  54    ftp://icf.llnl.gov/pub/python/busby/patches.961108.tgz.
  55
  56    This module is only useful to you if it happens to include code
  57    specific for your hardware and software environment.  If you can
  58    contribute OS-specific code for new platforms, or corrections for
  59    the code provided, it will be greatly appreciated.
  60
  61    ** Version 1.0: September 20, 1996.  Lee Busby, LLNL.
  62  */
  63
  64 #ifdef __cplusplus
  65 extern "C" {
  66 #endif
  67
  68 #include "Python.h"
  69 #include <signal.h>
  70
  71 #if defined(__FreeBSD__)
  72 #  include <ieeefp.h>
  73 #elif defined(__VMS)
  74 #define __NEW_STARLET
  75 #include <starlet.h>
  76 #include <ieeedef.h>
  77 #endif
  78
  79 #ifndef WANT_SIGFPE_HANDLER
  80 /* Define locally if they are not defined in Python.  This gives only
  81  * the limited control to induce a core dump in case of an exception.
  82  */
  83 #include <setjmp.h>
  84 static jmp_buf PyFPE_jbuf;
  85 static int PyFPE_counter = 0;
  86 #endif
  87
  88 typedef void Sigfunc(int);
  89 static Sigfunc sigfpe_handler;
  90 static void fpe_reset(Sigfunc *);
  91
  92 static PyObject *fpe_error;
  93 PyMODINIT_FUNC initfpectl(void);
  94 static PyObject *turnon_sigfpe            (PyObject *self,PyObject *args);
  95 static PyObject *turnoff_sigfpe           (PyObject *self,PyObject *args);
  96
  97 static PyMethodDef fpectl_methods[] = {
  98     {"turnon_sigfpe",            (PyCFunction) turnon_sigfpe,            METH_VARARGS},
  99     {"turnoff_sigfpe",           (PyCFunction) turnoff_sigfpe,           METH_VARARGS},
 100     {0,0}
 101 };
 102
 103 static PyObject *turnon_sigfpe(PyObject *self,PyObject *args)
 104 {
 105     /* Do any architecture-specific one-time only initialization here. */
 106
 107     fpe_reset(sigfpe_handler);
 108     Py_INCREF (Py_None);
 109     return Py_None;
 110 }
 111
 112 static void fpe_reset(Sigfunc *handler)
 113 {
 114     /* Reset the exception handling machinery, and reset the signal
 115      * handler for SIGFPE to the given handler.
 116      */
 117
 118 /*-- IRIX -----------------------------------------------------------------*/
 119 #if defined(sgi)
 120     /* See man page on handle_sigfpes -- must link with -lfpe
 121      * My usage doesn't follow the man page exactly.  Maybe somebody
 122      * else can explain handle_sigfpes to me....
 123      * cc -c -I/usr/local/python/include fpectlmodule.c
 124      * ld -shared -o fpectlmodule.so fpectlmodule.o -lfpe
 125      */
 126 #include <sigfpe.h>
 127     typedef void user_routine (unsigned[5], int[2]);
 128     typedef void abort_routine (unsigned long);
 129     handle_sigfpes(_OFF, 0,
 130                  (user_routine *)0,
 131                  _TURN_OFF_HANDLER_ON_ERROR,
 132                  NULL);
 133     handle_sigfpes(_ON, _EN_OVERFL | _EN_DIVZERO | _EN_INVALID,
 134                  (user_routine *)0,
 135                  _ABORT_ON_ERROR,
 136                  NULL);
 137     PyOS_setsig(SIGFPE, handler);
 138
 139 /*-- SunOS and Solaris ----------------------------------------------------*/
 140 #elif defined(sun)
 141     /* References: ieee_handler, ieee_sun, ieee_functions, and ieee_flags
 142        man pages (SunOS or Solaris)
 143        cc -c -I/usr/local/python/include fpectlmodule.c
 144        ld -G -o fpectlmodule.so -L/opt/SUNWspro/lib fpectlmodule.o -lsunmath -lm
 145      */
 146 #include <math.h>
 147 #ifndef _SUNMATH_H
 148     extern void nonstandard_arithmetic(void);
 149     extern int ieee_flags(const char*, const char*, const char*, char **);
 150     extern long ieee_handler(const char*, const char*, sigfpe_handler_type);
 151 #endif
 152
 153     char *mode="exception", *in="all", *out;
 154     (void) nonstandard_arithmetic();
 155     (void) ieee_flags("clearall",mode,in,&out);
 156     (void) ieee_handler("set","common",(sigfpe_handler_type)handler);
 157     PyOS_setsig(SIGFPE, handler);
 158
 159 /*-- HPUX -----------------------------------------------------------------*/
 160 #elif defined(__hppa) || defined(hppa)
 161     /* References:   fpsetmask man page */
 162     /* cc -Aa +z -c -I/usr/local/python/include fpectlmodule.c */
 163     /* ld -b -o fpectlmodule.sl fpectlmodule.o -lm */
 164 #include <math.h>
 165     fpsetdefaults();
 166     PyOS_setsig(SIGFPE, handler);
 167
 168 /*-- IBM AIX --------------------------------------------------------------*/
 169 #elif defined(__AIX) || defined(_AIX)
 170     /* References:   fp_trap, fp_enable man pages */
 171 #include <fptrap.h>
 172     fp_trap(FP_TRAP_SYNC);
 173     fp_enable(TRP_INVALID | TRP_DIV_BY_ZERO | TRP_OVERFLOW);
 174     PyOS_setsig(SIGFPE, handler);
 175
 176 /*-- DEC ALPHA OSF --------------------------------------------------------*/
 177 #elif defined(__alpha) && defined(__osf__)
 178     /* References:   exception_intro, ieee man pages */
 179     /* cc -c -I/usr/local/python/include fpectlmodule.c */
 180     /* ld -shared -o fpectlmodule.so fpectlmodule.o */
 181 #include <machine/fpu.h>
 182     unsigned long fp_control =
 183     IEEE_TRAP_ENABLE_INV | IEEE_TRAP_ENABLE_DZE | IEEE_TRAP_ENABLE_OVF;
 184     ieee_set_fp_control(fp_control);
 185     PyOS_setsig(SIGFPE, handler);
 186
 187 /*-- DEC ALPHA LINUX ------------------------------------------------------*/
 188 #elif defined(__alpha) && defined(linux)
 189 #include <asm/fpu.h>
 190     unsigned long fp_control =
 191     IEEE_TRAP_ENABLE_INV | IEEE_TRAP_ENABLE_DZE | IEEE_TRAP_ENABLE_OVF;
 192     ieee_set_fp_control(fp_control);
 193     PyOS_setsig(SIGFPE, handler);
 194
 195 /*-- DEC ALPHA VMS --------------------------------------------------------*/
 196 #elif defined(__ALPHA) && defined(__VMS)
 197         IEEE clrmsk;
 198         IEEE setmsk;
 199         clrmsk.ieee$q_flags =
 200                 IEEE$M_TRAP_ENABLE_UNF |  IEEE$M_TRAP_ENABLE_INE |
 201                  IEEE$M_MAP_UMZ;
 202         setmsk.ieee$q_flags =
 203                 IEEE$M_TRAP_ENABLE_INV | IEEE$M_TRAP_ENABLE_DZE |
 204                 IEEE$M_TRAP_ENABLE_OVF;
 205         sys$ieee_set_fp_control(&clrmsk, &setmsk, 0);
 206         PyOS_setsig(SIGFPE, handler);
 207
 208 /*-- HP IA64 VMS --------------------------------------------------------*/
 209 #elif defined(__ia64) && defined(__VMS)
 210     PyOS_setsig(SIGFPE, handler);
 211
 212 /*-- Cray Unicos ----------------------------------------------------------*/
 213 #elif defined(cray)
 214     /* UNICOS delivers SIGFPE by default, but no matherr */
 215 #ifdef HAS_LIBMSET
 216     libmset(-1);
 217 #endif
 218     PyOS_setsig(SIGFPE, handler);
 219
 220 /*-- FreeBSD ----------------------------------------------------------------*/
 221 #elif defined(__FreeBSD__)
 222     fpresetsticky(fpgetsticky());
 223     fpsetmask(FP_X_INV | FP_X_DZ | FP_X_OFL);
 224     PyOS_setsig(SIGFPE, handler);
 225
 226 /*-- Linux ----------------------------------------------------------------*/
 227 #elif defined(linux)
 228 #ifdef __GLIBC__
 229 #include <fpu_control.h>
 230 #else
 231 #include <i386/fpu_control.h>
 232 #endif
 233 #ifdef _FPU_SETCW
 234     {
 235         fpu_control_t cw = 0x1372;
 236         _FPU_SETCW(cw);
 237     }
 238 #else
 239     __setfpucw(0x1372);
 240 #endif
 241     PyOS_setsig(SIGFPE, handler);
 242
 243 /*-- Microsoft Windows, NT ------------------------------------------------*/
 244 #elif defined(_MSC_VER)
 245     /* Reference: Visual C++ Books Online 4.2,
 246        Run-Time Library Reference, _control87, _controlfp */
 247 #include <float.h>
 248     unsigned int cw = _EM_INVALID | _EM_ZERODIVIDE | _EM_OVERFLOW;
 249     (void)_controlfp(0, cw);
 250     PyOS_setsig(SIGFPE, handler);
 251
 252 /*-- Give Up --------------------------------------------------------------*/
 253 #else
 254     fputs("Operation not implemented\n", stderr);
 255 #endif
 256
 257 }
 258
 259 static PyObject *turnoff_sigfpe(PyObject *self,PyObject *args)
 260 {
 261 #ifdef __FreeBSD__
 262     fpresetsticky(fpgetsticky());
 263     fpsetmask(0);
 264 #elif defined(__VMS)
 265         IEEE clrmsk;
 266          clrmsk.ieee$q_flags =
 267                 IEEE$M_TRAP_ENABLE_UNF |  IEEE$M_TRAP_ENABLE_INE |
 268                 IEEE$M_MAP_UMZ | IEEE$M_TRAP_ENABLE_INV |
 269                 IEEE$M_TRAP_ENABLE_DZE | IEEE$M_TRAP_ENABLE_OVF |
 270                 IEEE$M_INHERIT;
 271         sys$ieee_set_fp_control(&clrmsk, 0, 0);
 272 #else
 273     fputs("Operation not implemented\n", stderr);
 274 #endif
 275     Py_INCREF(Py_None);
 276     return Py_None;
 277 }
 278
 279 static void sigfpe_handler(int signo)
 280 {
 281     fpe_reset(sigfpe_handler);
 282     if(PyFPE_counter) {
 283         longjmp(PyFPE_jbuf, 1);
 284     } else {
 285         Py_FatalError("Unprotected floating point exception");
 286     }
 287 }
 288
 289 PyMODINIT_FUNC initfpectl(void)
 290 {
 291     PyObject *m, *d;
 292     m = Py_InitModule("fpectl", fpectl_methods);
 293     if (m == NULL)
 294         return;
 295     d = PyModule_GetDict(m);
 296     fpe_error = PyErr_NewException("fpectl.error", NULL, NULL);
 297     if (fpe_error != NULL)
 298         PyDict_SetItemString(d, "error", fpe_error);
 299 }
 300
 301 #ifdef __cplusplus
 302 }
 303 #endif