| /* 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 ; |
| } |