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
65extern "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>
84static jmp_buf PyFPE_jbuf;
85static int PyFPE_counter = 0;
86#endif
87
88typedef void Sigfunc(int);
89static Sigfunc sigfpe_handler;
90static void fpe_reset(Sigfunc *);
91
92static PyObject *fpe_error;
93PyMODINIT_FUNC initfpectl(void);
94static PyObject *turnon_sigfpe            (PyObject *self,PyObject *args);
95static PyObject *turnoff_sigfpe           (PyObject *self,PyObject *args);
96
97static PyMethodDef fpectl_methods[] = {
98    {"turnon_sigfpe",            (PyCFunction) turnon_sigfpe,            METH_VARARGS},
99    {"turnoff_sigfpe",           (PyCFunction) turnoff_sigfpe,           METH_VARARGS},
100    {0,0}
101};
102
103static 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
112static 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$ieee_set_fp_control(&clrmsk, &setmsk, 0);
206        PyOS_setsig(SIGFPE, handler);
207
208/*-- HP IA64 VMS --------------------------------------------------------*/
209#elif defined(__ia64) && defined(__VMS)
210    PyOS_setsig(SIGFPE, handler);
211
212/*-- Cray Unicos ----------------------------------------------------------*/
213#elif defined(cray)
214    /* UNICOS delivers SIGFPE by default, but no matherr */
215#ifdef HAS_LIBMSET
216    libmset(-1);
217#endif
218    PyOS_setsig(SIGFPE, handler);
219
220/*-- FreeBSD ----------------------------------------------------------------*/
221#elif defined(__FreeBSD__)
222    fpresetsticky(fpgetsticky());
223    fpsetmask(FP_X_INV | FP_X_DZ | FP_X_OFL);
224    PyOS_setsig(SIGFPE, handler);
225
226/*-- Linux ----------------------------------------------------------------*/
227#elif defined(linux)
228#ifdef __GLIBC__
229#include <fpu_control.h>
230#else
231#include <i386/fpu_control.h>
232#endif
233#ifdef _FPU_SETCW
234    {
235        fpu_control_t cw = 0x1372;
236        _FPU_SETCW(cw);
237    }
238#else
239    __setfpucw(0x1372);
240#endif
241    PyOS_setsig(SIGFPE, handler);
242
243/*-- Microsoft Windows, NT ------------------------------------------------*/
244#elif defined(_MSC_VER)
245    /* Reference: Visual C++ Books Online 4.2,
246       Run-Time Library Reference, _control87, _controlfp */
247#include <float.h>
248    unsigned int cw = _EM_INVALID | _EM_ZERODIVIDE | _EM_OVERFLOW;
249    (void)_controlfp(0, cw);
250    PyOS_setsig(SIGFPE, handler);
251
252/*-- Give Up --------------------------------------------------------------*/
253#else
254    fputs("Operation not implemented\n", stderr);
255#endif
256
257}
258
259static PyObject *turnoff_sigfpe(PyObject *self,PyObject *args)
260{
261#ifdef __FreeBSD__
262    fpresetsticky(fpgetsticky());
263    fpsetmask(0);
264#elif defined(__VMS)
265        IEEE clrmsk;
266         clrmsk.ieee$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
279static 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
289PyMODINIT_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
304