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Diffstat (limited to 'gsl-1.9/ieee-utils/fp-tru64.c')
| -rw-r--r-- | gsl-1.9/ieee-utils/fp-tru64.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/gsl-1.9/ieee-utils/fp-tru64.c b/gsl-1.9/ieee-utils/fp-tru64.c new file mode 100644 index 0000000..1051f1f --- /dev/null +++ b/gsl-1.9/ieee-utils/fp-tru64.c @@ -0,0 +1,176 @@ +/* ieee-utils/fp-tru64.c + * + * Copyright (C) 1996, 1997, 1998, 1999, 2000 Tim Mooney + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or (at + * your option) any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + */ + + +/* + * Under Compaq's Unix with the silly name, read the man pages for read_rnd, + * write_rnd, and ieee(3) for more information on the functions used here. + * + * Note that enabling control of dynamic rounding mode (via write_rnd) requires + * that you pass a special flag to your C compiler. For Compaq's C compiler + * the flag is `-fprm d', for gcc it's `-mfp-rounding-mode=d'. + * + * Enabling the trap control (via ieee_set_fp_control) also requires a + * flag be passed to the C compiler. The flag for Compaq's C compiler + * is `-ieee' and for gcc it's `-mieee'. + + * We have not implemented the `inexact' case, since it is rarely used + * and requires the library being built with an additional compiler + * flag that can degrade performance for everything else. If you need + * to add support for `inexact' the relevant flag for Compaq's + * compiler is `-ieee_with_inexact', and the flag for gcc is + * `-mieee-with-inexact'. + * + * Problem have been reported with the "fixed" float.h installed with + * gcc-2.95 lacking some of the definitions in the system float.h (the + * symptoms are errors like: `FP_RND_RN' undeclared). To work around + * this we can include the system float.h before the gcc version, e.g. + * + * #include "/usr/include/float.h" + * #include <float.h> + */ + +#include <float.h> + +#ifndef FP_RND_RN +# undef _FLOAT_H_ +# include "/usr/include/float.h" +# undef _FLOAT_H_ +# include <float.h> +#endif + +#include <machine/fpu.h> +#include <stdio.h> +#include <gsl/gsl_ieee_utils.h> +#include <gsl/gsl_errno.h> + +int +gsl_ieee_set_mode (int precision, int rounding, int exception_mask) +{ + unsigned long int mode = 0 ; + unsigned int rnd = 0 ; + +/* I'm actually not completely sure that the alpha only supports default + * precisions rounding, but I couldn't find any information regarding this, so + * it seems safe to assume this for now until it's proven otherwise. + */ + + switch (precision) + { + case GSL_IEEE_SINGLE_PRECISION: + GSL_ERROR ("Tru64 Unix on the alpha only supports default precision rounding", + GSL_EUNSUP) ; + break ; + case GSL_IEEE_DOUBLE_PRECISION: + GSL_ERROR ("Tru64 Unix on the alpha only supports default precision rounding", + GSL_EUNSUP) ; + break ; + case GSL_IEEE_EXTENDED_PRECISION: + GSL_ERROR ("Tru64 Unix on the alpha only supports default precision rounding", + GSL_EUNSUP) ; + break ; + } + + + switch (rounding) + { + case GSL_IEEE_ROUND_TO_NEAREST: + rnd = FP_RND_RN ; + write_rnd (rnd) ; + break ; + case GSL_IEEE_ROUND_DOWN: + rnd = FP_RND_RM ; + write_rnd (rnd) ; + break ; + case GSL_IEEE_ROUND_UP: + rnd = FP_RND_RP ; + write_rnd (rnd) ; + break ; + case GSL_IEEE_ROUND_TO_ZERO: + rnd = FP_RND_RZ ; + write_rnd (rnd) ; + break ; + default: + rnd = FP_RND_RN ; + write_rnd (rnd) ; + } + + /* Turn on all the exceptions apart from 'inexact' */ + + /* from the ieee(3) man page: + * IEEE_TRAP_ENABLE_INV -> Invalid operation + * IEEE_TRAP_ENABLE_DZE -> Divide by 0 + * IEEE_TRAP_ENABLE_OVF -> Overflow + * IEEE_TRAP_ENABLE_UNF -> Underflow + * IEEE_TRAP_ENABLE_INE -> Inexact (requires special option to C compiler) + * IEEE_TRAP_ENABLE_DNO -> denormal operand + * Note: IEEE_TRAP_ENABLE_DNO is not supported on OSF 3.x or Digital Unix + * 4.0 - 4.0d(?). + * IEEE_TRAP_ENABLE_MASK -> mask of all the trap enables + * IEEE_MAP_DMZ -> map denormal inputs to zero + * IEEE_MAP_UMZ -> map underflow results to zero + */ + + mode = IEEE_TRAP_ENABLE_INV | IEEE_TRAP_ENABLE_DZE | IEEE_TRAP_ENABLE_OVF + | IEEE_TRAP_ENABLE_UNF ; + + if (exception_mask & GSL_IEEE_MASK_INVALID) + mode &= ~ IEEE_TRAP_ENABLE_INV ; + + if (exception_mask & GSL_IEEE_MASK_DENORMALIZED) + { +#ifdef IEEE_TRAP_ENABLE_DNO + mode &= ~ IEEE_TRAP_ENABLE_DNO ; +#else + GSL_ERROR ("Sorry, this version of Digital Unix does not support denormalized operands", GSL_EUNSUP) ; +#endif + } + + if (exception_mask & GSL_IEEE_MASK_DIVISION_BY_ZERO) + mode &= ~ IEEE_TRAP_ENABLE_DZE ; + + if (exception_mask & GSL_IEEE_MASK_OVERFLOW) + mode &= ~ IEEE_TRAP_ENABLE_OVF ; + + if (exception_mask & GSL_IEEE_MASK_UNDERFLOW) + mode &= ~ IEEE_TRAP_ENABLE_UNF ; + + if (exception_mask & GSL_IEEE_TRAP_INEXACT) + { + /* To implement this would require a special flag to the C + compiler which can cause degraded performance */ + + GSL_ERROR ("Sorry, GSL does not implement trap-inexact for Tru64 Unix on the alpha - see fp-tru64.c for details", GSL_EUNSUP) ; + + /* In case you need to add it, the appropriate line would be + * + * mode |= IEEE_TRAP_ENABLE_INE ; + * + */ + + } + else + { + mode &= ~ IEEE_TRAP_ENABLE_INE ; + } + + ieee_set_fp_control (mode) ; + + return GSL_SUCCESS ; +} |