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gcc/libdecnumber/decContext.c

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/* Decimal context module for the decNumber C Library.
Copyright (C) 2005 Free Software Foundation, Inc.
Contributed by IBM Corporation. Author Mike Cowlishaw.
This file is part of GCC.
GCC 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, or (at your option) any later
version.
GCC 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 GCC; see the file COPYING. If not, write to the Free
Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301, USA. */
/* This module compirises the routines for handling the arithmetic
context structures. */
#include <string.h> /* for strcmp */
#include "config.h"
#include "decContext.h" /* context and base types */
#include "decNumberLocal.h" /* decNumber local types, etc. */
/* ------------------------------------------------------------------ */
/* decContextDefault -- initialize a context structure */
/* */
/* context is the structure to be initialized */
/* kind selects the required set of default values, one of: */
/* DEC_INIT_BASE -- select ANSI X3-274 defaults */
/* DEC_INIT_DECIMAL32 -- select IEEE 754r defaults, 32-bit */
/* DEC_INIT_DECIMAL64 -- select IEEE 754r defaults, 64-bit */
/* DEC_INIT_DECIMAL128 -- select IEEE 754r defaults, 128-bit */
/* For any other value a valid context is returned, but with */
/* Invalid_operation set in the status field. */
/* returns a context structure with the appropriate initial values. */
/* ------------------------------------------------------------------ */
decContext *
decContextDefault (decContext * context, Int kind)
{
/* set defaults... */
context->digits = 9; /* 9 digits */
context->emax = DEC_MAX_EMAX; /* 9-digit exponents */
context->emin = DEC_MIN_EMIN; /* .. balanced */
context->round = DEC_ROUND_HALF_UP; /* 0.5 rises */
context->traps = DEC_Errors; /* all but informational */
context->status = 0; /* cleared */
context->clamp = 0; /* no clamping */
#if DECSUBSET
context->extended = 0; /* cleared */
#endif
switch (kind)
{
case DEC_INIT_BASE:
/* [use defaults] */
break;
case DEC_INIT_DECIMAL32:
context->digits = 7; /* digits */
context->emax = 96; /* Emax */
context->emin = -95; /* Emin */
context->round = DEC_ROUND_HALF_EVEN; /* 0.5 to nearest even */
context->traps = 0; /* no traps set */
context->clamp = 1; /* clamp exponents */
#if DECSUBSET
context->extended = 1; /* set */
#endif
break;
case DEC_INIT_DECIMAL64:
context->digits = 16; /* digits */
context->emax = 384; /* Emax */
context->emin = -383; /* Emin */
context->round = DEC_ROUND_HALF_EVEN; /* 0.5 to nearest even */
context->traps = 0; /* no traps set */
context->clamp = 1; /* clamp exponents */
#if DECSUBSET
context->extended = 1; /* set */
#endif
break;
case DEC_INIT_DECIMAL128:
context->digits = 34; /* digits */
context->emax = 6144; /* Emax */
context->emin = -6143; /* Emin */
context->round = DEC_ROUND_HALF_EVEN; /* 0.5 to nearest even */
context->traps = 0; /* no traps set */
context->clamp = 1; /* clamp exponents */
#if DECSUBSET
context->extended = 1; /* set */
#endif
break;
default: /* invalid Kind */
/* use defaults, and .. */
decContextSetStatus (context, DEC_Invalid_operation); /* trap */
}
return context;
} /* decContextDefault */
/* ------------------------------------------------------------------ */
/* decContextStatusToString -- convert status flags to a string */
/* */
/* context is a context with valid status field */
/* */
/* returns a constant string describing the condition. If multiple */
/* (or no) flags are set, a generic constant message is returned. */
/* ------------------------------------------------------------------ */
const char *
decContextStatusToString (const decContext * context)
{
Int status = context->status;
if (status == DEC_Conversion_syntax)
return DEC_Condition_CS;
if (status == DEC_Division_by_zero)
return DEC_Condition_DZ;
if (status == DEC_Division_impossible)
return DEC_Condition_DI;
if (status == DEC_Division_undefined)
return DEC_Condition_DU;
if (status == DEC_Inexact)
return DEC_Condition_IE;
if (status == DEC_Insufficient_storage)
return DEC_Condition_IS;
if (status == DEC_Invalid_context)
return DEC_Condition_IC;
if (status == DEC_Invalid_operation)
return DEC_Condition_IO;
#if DECSUBSET
if (status == DEC_Lost_digits)
return DEC_Condition_LD;
#endif
if (status == DEC_Overflow)
return DEC_Condition_OV;
if (status == DEC_Clamped)
return DEC_Condition_PA;
if (status == DEC_Rounded)
return DEC_Condition_RO;
if (status == DEC_Subnormal)
return DEC_Condition_SU;
if (status == DEC_Underflow)
return DEC_Condition_UN;
if (status == 0)
return DEC_Condition_ZE;
return DEC_Condition_MU; /* Multiple errors */
} /* decContextStatusToString */
/* ------------------------------------------------------------------ */
/* decContextSetStatusFromString -- set status from a string */
/* */
/* context is the controlling context */
/* string is a string exactly equal to one that might be returned */
/* by decContextStatusToString */
/* */
/* The status bit corresponding to the string is set, and a trap */
/* is raised if appropriate. */
/* */
/* returns the context structure, unless the string is equal to */
/* DEC_Condition_MU or is not recognized. In these cases NULL is */
/* returned. */
/* ------------------------------------------------------------------ */
decContext *
decContextSetStatusFromString (decContext * context, const char *string)
{
if (strcmp (string, DEC_Condition_CS) == 0)
return decContextSetStatus (context, DEC_Conversion_syntax);
if (strcmp (string, DEC_Condition_DZ) == 0)
return decContextSetStatus (context, DEC_Division_by_zero);
if (strcmp (string, DEC_Condition_DI) == 0)
return decContextSetStatus (context, DEC_Division_impossible);
if (strcmp (string, DEC_Condition_DU) == 0)
return decContextSetStatus (context, DEC_Division_undefined);
if (strcmp (string, DEC_Condition_IE) == 0)
return decContextSetStatus (context, DEC_Inexact);
if (strcmp (string, DEC_Condition_IS) == 0)
return decContextSetStatus (context, DEC_Insufficient_storage);
if (strcmp (string, DEC_Condition_IC) == 0)
return decContextSetStatus (context, DEC_Invalid_context);
if (strcmp (string, DEC_Condition_IO) == 0)
return decContextSetStatus (context, DEC_Invalid_operation);
#if DECSUBSET
if (strcmp (string, DEC_Condition_LD) == 0)
return decContextSetStatus (context, DEC_Lost_digits);
#endif
if (strcmp (string, DEC_Condition_OV) == 0)
return decContextSetStatus (context, DEC_Overflow);
if (strcmp (string, DEC_Condition_PA) == 0)
return decContextSetStatus (context, DEC_Clamped);
if (strcmp (string, DEC_Condition_RO) == 0)
return decContextSetStatus (context, DEC_Rounded);
if (strcmp (string, DEC_Condition_SU) == 0)
return decContextSetStatus (context, DEC_Subnormal);
if (strcmp (string, DEC_Condition_UN) == 0)
return decContextSetStatus (context, DEC_Underflow);
if (strcmp (string, DEC_Condition_ZE) == 0)
return context;
return NULL; /* Multiple status, or unknown */
} /* decContextSetStatusFromString */
/* ------------------------------------------------------------------ */
/* decContextSetStatus -- set status and raise trap if appropriate */
/* */
/* context is the controlling context */
/* status is the DEC_ exception code */
/* returns the context structure */
/* */
/* Control may never return from this routine, if there is a signal */
/* handler and it takes a long jump. */
/* ------------------------------------------------------------------ */
decContext *
decContextSetStatus (decContext * context, uInt status)
{
context->status |= status;
if (status & context->traps)
raise (SIGFPE);
return context;
} /* decContextSetStatus */
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