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229 lines
9.8 KiB
C
229 lines
9.8 KiB
C
/* Decimal context module for the decNumber C Library.
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Copyright (C) 2005 Free Software Foundation, Inc.
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Contributed by IBM Corporation. Author Mike Cowlishaw.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 2, or (at your option) any later
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version.
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In addition to the permissions in the GNU General Public License,
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the Free Software Foundation gives you unlimited permission to link
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the compiled version of this file into combinations with other
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programs, and to distribute those combinations without any
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restriction coming from the use of this file. (The General Public
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License restrictions do apply in other respects; for example, they
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cover modification of the file, and distribution when not linked
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into a combine executable.)
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING. If not, write to the Free
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Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301, USA. */
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/* This module compirises the routines for handling the arithmetic
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context structures. */
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#include <string.h> /* for strcmp */
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#include "config.h"
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#include "decContext.h" /* context and base types */
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#include "decNumberLocal.h" /* decNumber local types, etc. */
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/* ------------------------------------------------------------------ */
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/* decContextDefault -- initialize a context structure */
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/* */
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/* context is the structure to be initialized */
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/* kind selects the required set of default values, one of: */
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/* DEC_INIT_BASE -- select ANSI X3-274 defaults */
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/* DEC_INIT_DECIMAL32 -- select IEEE 754r defaults, 32-bit */
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/* DEC_INIT_DECIMAL64 -- select IEEE 754r defaults, 64-bit */
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/* DEC_INIT_DECIMAL128 -- select IEEE 754r defaults, 128-bit */
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/* For any other value a valid context is returned, but with */
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/* Invalid_operation set in the status field. */
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/* returns a context structure with the appropriate initial values. */
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/* ------------------------------------------------------------------ */
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decContext *
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decContextDefault (decContext * context, Int kind)
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{
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/* set defaults... */
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context->digits = 9; /* 9 digits */
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context->emax = DEC_MAX_EMAX; /* 9-digit exponents */
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context->emin = DEC_MIN_EMIN; /* .. balanced */
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context->round = DEC_ROUND_HALF_UP; /* 0.5 rises */
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context->traps = DEC_Errors; /* all but informational */
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context->status = 0; /* cleared */
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context->clamp = 0; /* no clamping */
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#if DECSUBSET
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context->extended = 0; /* cleared */
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#endif
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switch (kind)
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{
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case DEC_INIT_BASE:
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/* [use defaults] */
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break;
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case DEC_INIT_DECIMAL32:
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context->digits = 7; /* digits */
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context->emax = 96; /* Emax */
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context->emin = -95; /* Emin */
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context->round = DEC_ROUND_HALF_EVEN; /* 0.5 to nearest even */
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context->traps = 0; /* no traps set */
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context->clamp = 1; /* clamp exponents */
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#if DECSUBSET
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context->extended = 1; /* set */
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#endif
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break;
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case DEC_INIT_DECIMAL64:
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context->digits = 16; /* digits */
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context->emax = 384; /* Emax */
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context->emin = -383; /* Emin */
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context->round = DEC_ROUND_HALF_EVEN; /* 0.5 to nearest even */
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context->traps = 0; /* no traps set */
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context->clamp = 1; /* clamp exponents */
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#if DECSUBSET
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context->extended = 1; /* set */
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#endif
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break;
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case DEC_INIT_DECIMAL128:
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context->digits = 34; /* digits */
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context->emax = 6144; /* Emax */
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context->emin = -6143; /* Emin */
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context->round = DEC_ROUND_HALF_EVEN; /* 0.5 to nearest even */
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context->traps = 0; /* no traps set */
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context->clamp = 1; /* clamp exponents */
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#if DECSUBSET
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context->extended = 1; /* set */
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#endif
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break;
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default: /* invalid Kind */
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/* use defaults, and .. */
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decContextSetStatus (context, DEC_Invalid_operation); /* trap */
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}
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return context;
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} /* decContextDefault */
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/* ------------------------------------------------------------------ */
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/* decContextStatusToString -- convert status flags to a string */
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/* */
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/* context is a context with valid status field */
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/* */
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/* returns a constant string describing the condition. If multiple */
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/* (or no) flags are set, a generic constant message is returned. */
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/* ------------------------------------------------------------------ */
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const char *
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decContextStatusToString (const decContext * context)
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{
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Int status = context->status;
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if (status == DEC_Conversion_syntax)
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return DEC_Condition_CS;
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if (status == DEC_Division_by_zero)
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return DEC_Condition_DZ;
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if (status == DEC_Division_impossible)
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return DEC_Condition_DI;
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if (status == DEC_Division_undefined)
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return DEC_Condition_DU;
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if (status == DEC_Inexact)
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return DEC_Condition_IE;
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if (status == DEC_Insufficient_storage)
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return DEC_Condition_IS;
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if (status == DEC_Invalid_context)
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return DEC_Condition_IC;
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if (status == DEC_Invalid_operation)
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return DEC_Condition_IO;
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#if DECSUBSET
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if (status == DEC_Lost_digits)
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return DEC_Condition_LD;
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#endif
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if (status == DEC_Overflow)
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return DEC_Condition_OV;
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if (status == DEC_Clamped)
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return DEC_Condition_PA;
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if (status == DEC_Rounded)
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return DEC_Condition_RO;
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if (status == DEC_Subnormal)
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return DEC_Condition_SU;
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if (status == DEC_Underflow)
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return DEC_Condition_UN;
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if (status == 0)
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return DEC_Condition_ZE;
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return DEC_Condition_MU; /* Multiple errors */
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} /* decContextStatusToString */
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/* ------------------------------------------------------------------ */
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/* decContextSetStatusFromString -- set status from a string */
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/* */
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/* context is the controlling context */
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/* string is a string exactly equal to one that might be returned */
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/* by decContextStatusToString */
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/* */
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/* The status bit corresponding to the string is set, and a trap */
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/* is raised if appropriate. */
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/* */
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/* returns the context structure, unless the string is equal to */
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/* DEC_Condition_MU or is not recognized. In these cases NULL is */
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/* returned. */
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/* ------------------------------------------------------------------ */
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decContext *
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decContextSetStatusFromString (decContext * context, const char *string)
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{
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if (strcmp (string, DEC_Condition_CS) == 0)
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return decContextSetStatus (context, DEC_Conversion_syntax);
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if (strcmp (string, DEC_Condition_DZ) == 0)
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return decContextSetStatus (context, DEC_Division_by_zero);
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if (strcmp (string, DEC_Condition_DI) == 0)
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return decContextSetStatus (context, DEC_Division_impossible);
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if (strcmp (string, DEC_Condition_DU) == 0)
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return decContextSetStatus (context, DEC_Division_undefined);
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if (strcmp (string, DEC_Condition_IE) == 0)
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return decContextSetStatus (context, DEC_Inexact);
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if (strcmp (string, DEC_Condition_IS) == 0)
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return decContextSetStatus (context, DEC_Insufficient_storage);
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if (strcmp (string, DEC_Condition_IC) == 0)
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return decContextSetStatus (context, DEC_Invalid_context);
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if (strcmp (string, DEC_Condition_IO) == 0)
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return decContextSetStatus (context, DEC_Invalid_operation);
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#if DECSUBSET
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if (strcmp (string, DEC_Condition_LD) == 0)
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return decContextSetStatus (context, DEC_Lost_digits);
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#endif
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if (strcmp (string, DEC_Condition_OV) == 0)
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return decContextSetStatus (context, DEC_Overflow);
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if (strcmp (string, DEC_Condition_PA) == 0)
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return decContextSetStatus (context, DEC_Clamped);
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if (strcmp (string, DEC_Condition_RO) == 0)
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return decContextSetStatus (context, DEC_Rounded);
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if (strcmp (string, DEC_Condition_SU) == 0)
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return decContextSetStatus (context, DEC_Subnormal);
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if (strcmp (string, DEC_Condition_UN) == 0)
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return decContextSetStatus (context, DEC_Underflow);
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if (strcmp (string, DEC_Condition_ZE) == 0)
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return context;
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return NULL; /* Multiple status, or unknown */
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} /* decContextSetStatusFromString */
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/* ------------------------------------------------------------------ */
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/* decContextSetStatus -- set status and raise trap if appropriate */
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/* */
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/* context is the controlling context */
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/* status is the DEC_ exception code */
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/* returns the context structure */
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/* */
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/* Control may never return from this routine, if there is a signal */
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/* handler and it takes a long jump. */
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/* ------------------------------------------------------------------ */
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decContext *
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decContextSetStatus (decContext * context, uInt status)
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{
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context->status |= status;
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if (status & context->traps)
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raise (SIGFPE);
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return context;
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} /* decContextSetStatus */
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