--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libdecnumber/decContext.c	Fri Jul 17 14:47:48 2009 +0900
@@ -0,0 +1,427 @@
+/* Decimal context module for the decNumber C Library.
+   Copyright (C) 2005, 2007, 2009 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 3, 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.
+
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+<http://www.gnu.org/licenses/>.  */
+
+/* ------------------------------------------------------------------ */
+/* Decimal Context module					      */
+/* ------------------------------------------------------------------ */
+/* This module comprises the routines for handling arithmetic	      */
+/* context structures.						      */
+/* ------------------------------------------------------------------ */
+
+#include <string.h>	      /* for strcmp */
+#include <stdio.h>	      /* for printf if DECCHECK */
+#include "dconfig.h"	      /* for GCC definitions */
+#include "decContext.h"	      /* context and base types */
+#include "decNumberLocal.h"   /* decNumber local types, etc. */
+
+#if DECCHECK
+/* compile-time endian tester [assumes sizeof(Int)>1] */
+static	const  Int mfcone=1;		     /* constant 1 */
+static	const  Flag *mfctop=(Flag *)&mfcone; /* -> top byte */
+#define LITEND *mfctop		   /* named flag; 1=little-endian */
+#endif
+
+/* ------------------------------------------------------------------ */
+/* round-for-reround digits					      */
+/* ------------------------------------------------------------------ */
+const uByte DECSTICKYTAB[10]={1,1,2,3,4,6,6,7,8,9}; /* used if sticky */
+
+/* ------------------------------------------------------------------ */
+/* Powers of ten (powers[n]==10**n, 0<=n<=9)			      */
+/* ------------------------------------------------------------------ */
+const uInt DECPOWERS[10]={1, 10, 100, 1000, 10000, 100000, 1000000,
+			  10000000, 100000000, 1000000000};
+
+/* ------------------------------------------------------------------ */
+/* decContextClearStatus -- clear bits in current status	      */
+/*								      */
+/*  context is the context structure to be queried		      */
+/*  mask indicates the bits to be cleared (the status bit that	      */
+/*    corresponds to each 1 bit in the mask is cleared)		      */
+/*  returns context						      */
+/*								      */
+/* No error is possible.					      */
+/* ------------------------------------------------------------------ */
+decContext *decContextClearStatus(decContext *context, uInt mask) {
+  context->status&=~mask;
+  return context;
+  } /* decContextClearStatus */
+
+/* ------------------------------------------------------------------ */
+/* 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 */
+    }
+
+  #if DECCHECK
+  if (LITEND!=DECLITEND) {
+    const char *adj;
+    if (LITEND) adj="little";
+	   else adj="big";
+    printf("Warning: DECLITEND is set to %d, but this computer appears to be %s-endian\n",
+	   DECLITEND, adj);
+    }
+  #endif
+  return context;} /* decContextDefault */
+
+/* ------------------------------------------------------------------ */
+/* decContextGetRounding -- return current rounding mode	      */
+/*								      */
+/*  context is the context structure to be queried		      */
+/*  returns the rounding mode					      */
+/*								      */
+/* No error is possible.					      */
+/* ------------------------------------------------------------------ */
+enum rounding decContextGetRounding(decContext *context) {
+  return context->round;
+  } /* decContextGetRounding */
+
+/* ------------------------------------------------------------------ */
+/* decContextGetStatus -- return current status			      */
+/*								      */
+/*  context is the context structure to be queried		      */
+/*  returns status						      */
+/*								      */
+/* No error is possible.					      */
+/* ------------------------------------------------------------------ */
+uInt decContextGetStatus(decContext *context) {
+  return context->status;
+  } /* decContextGetStatus */
+
+/* ------------------------------------------------------------------ */
+/* decContextRestoreStatus -- restore bits in current status	      */
+/*								      */
+/*  context is the context structure to be updated		      */
+/*  newstatus is the source for the bits to be restored		      */
+/*  mask indicates the bits to be restored (the status bit that	      */
+/*    corresponds to each 1 bit in the mask is set to the value of    */
+/*    the correspnding bit in newstatus)			      */
+/*  returns context						      */
+/*								      */
+/* No error is possible.					      */
+/* ------------------------------------------------------------------ */
+decContext *decContextRestoreStatus(decContext *context,
+				    uInt newstatus, uInt mask) {
+  context->status&=~mask;		/* clear the selected bits */
+  context->status|=(mask&newstatus);	/* or in the new bits */
+  return context;
+  } /* decContextRestoreStatus */
+
+/* ------------------------------------------------------------------ */
+/* decContextSaveStatus -- save bits in current status		      */
+/*								      */
+/*  context is the context structure to be queried		      */
+/*  mask indicates the bits to be saved (the status bits that	      */
+/*    correspond to each 1 bit in the mask are saved)		      */
+/*  returns the AND of the mask and the current status		      */
+/*								      */
+/* No error is possible.					      */
+/* ------------------------------------------------------------------ */
+uInt decContextSaveStatus(decContext *context, uInt mask) {
+  return context->status&mask;
+  } /* decContextSaveStatus */
+
+/* ------------------------------------------------------------------ */
+/* decContextSetRounding -- set current rounding mode		      */
+/*								      */
+/*  context is the context structure to be updated		      */
+/*  newround is the value which will replace the current mode	      */
+/*  returns context						      */
+/*								      */
+/* No error is possible.					      */
+/* ------------------------------------------------------------------ */
+decContext *decContextSetRounding(decContext *context,
+				  enum rounding newround) {
+  context->round=newround;
+  return context;
+  } /* decContextSetRounding */
+
+/* ------------------------------------------------------------------ */
+/* decContextSetStatus -- set status and raise trap if appropriate    */
+/*								      */
+/*  context is the context structure to be updated		      */
+/*  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 */
+
+/* ------------------------------------------------------------------ */
+/* decContextSetStatusFromString -- set status from a string + trap   */
+/*								      */
+/*  context is the context structure to be updated		      */
+/*  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 */
+
+/* ------------------------------------------------------------------ */
+/* decContextSetStatusFromStringQuiet -- set status from a string     */
+/*								      */
+/*  context is the context structure to be updated		      */
+/*  string is a string exactly equal to one that might be returned    */
+/*	      by decContextStatusToString			      */
+/*								      */
+/*  The status bit corresponding to the string is set; no trap is     */
+/*  raised.							      */
+/*								      */
+/*  returns the context structure, unless the string is equal to      */
+/*    DEC_Condition_MU or is not recognized.  In these cases NULL is  */
+/*    returned.							      */
+/* ------------------------------------------------------------------ */
+decContext * decContextSetStatusFromStringQuiet(decContext *context,
+						const char *string) {
+  if (strcmp(string, DEC_Condition_CS)==0)
+    return decContextSetStatusQuiet(context, DEC_Conversion_syntax);
+  if (strcmp(string, DEC_Condition_DZ)==0)
+    return decContextSetStatusQuiet(context, DEC_Division_by_zero);
+  if (strcmp(string, DEC_Condition_DI)==0)
+    return decContextSetStatusQuiet(context, DEC_Division_impossible);
+  if (strcmp(string, DEC_Condition_DU)==0)
+    return decContextSetStatusQuiet(context, DEC_Division_undefined);
+  if (strcmp(string, DEC_Condition_IE)==0)
+    return decContextSetStatusQuiet(context, DEC_Inexact);
+  if (strcmp(string, DEC_Condition_IS)==0)
+    return decContextSetStatusQuiet(context, DEC_Insufficient_storage);
+  if (strcmp(string, DEC_Condition_IC)==0)
+    return decContextSetStatusQuiet(context, DEC_Invalid_context);
+  if (strcmp(string, DEC_Condition_IO)==0)
+    return decContextSetStatusQuiet(context, DEC_Invalid_operation);
+  #if DECSUBSET
+  if (strcmp(string, DEC_Condition_LD)==0)
+    return decContextSetStatusQuiet(context, DEC_Lost_digits);
+  #endif
+  if (strcmp(string, DEC_Condition_OV)==0)
+    return decContextSetStatusQuiet(context, DEC_Overflow);
+  if (strcmp(string, DEC_Condition_PA)==0)
+    return decContextSetStatusQuiet(context, DEC_Clamped);
+  if (strcmp(string, DEC_Condition_RO)==0)
+    return decContextSetStatusQuiet(context, DEC_Rounded);
+  if (strcmp(string, DEC_Condition_SU)==0)
+    return decContextSetStatusQuiet(context, DEC_Subnormal);
+  if (strcmp(string, DEC_Condition_UN)==0)
+    return decContextSetStatusQuiet(context, DEC_Underflow);
+  if (strcmp(string, DEC_Condition_ZE)==0)
+    return context;
+  return NULL;	/* Multiple status, or unknown */
+  } /* decContextSetStatusFromStringQuiet */
+
+/* ------------------------------------------------------------------ */
+/* decContextSetStatusQuiet -- set status without trap		      */
+/*								      */
+/*  context is the context structure to be updated		      */
+/*  status  is the DEC_ exception code				      */
+/*  returns the context structure				      */
+/*								      */
+/* No error is possible.					      */
+/* ------------------------------------------------------------------ */
+decContext * decContextSetStatusQuiet(decContext *context, uInt status) {
+  context->status|=status;
+  return context;} /* decContextSetStatusQuiet */
+
+/* ------------------------------------------------------------------ */
+/* 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;
+
+  /* test the five IEEE first, as some of the others are ambiguous when */
+  /* DECEXTFLAG=0 */
+  if (status==DEC_Invalid_operation    ) return DEC_Condition_IO;
+  if (status==DEC_Division_by_zero     ) return DEC_Condition_DZ;
+  if (status==DEC_Overflow	       ) return DEC_Condition_OV;
+  if (status==DEC_Underflow	       ) return DEC_Condition_UN;
+  if (status==DEC_Inexact	       ) return DEC_Condition_IE;
+
+  if (status==DEC_Division_impossible  ) return DEC_Condition_DI;
+  if (status==DEC_Division_undefined   ) return DEC_Condition_DU;
+  if (status==DEC_Rounded	       ) return DEC_Condition_RO;
+  if (status==DEC_Clamped	       ) return DEC_Condition_PA;
+  if (status==DEC_Subnormal	       ) return DEC_Condition_SU;
+  if (status==DEC_Conversion_syntax    ) return DEC_Condition_CS;
+  if (status==DEC_Insufficient_storage ) return DEC_Condition_IS;
+  if (status==DEC_Invalid_context      ) return DEC_Condition_IC;
+  #if DECSUBSET
+  if (status==DEC_Lost_digits	       ) return DEC_Condition_LD;
+  #endif
+  if (status==0			       ) return DEC_Condition_ZE;
+  return DEC_Condition_MU;  /* Multiple errors */
+  } /* decContextStatusToString */
+
+/* ------------------------------------------------------------------ */
+/* decContextTestSavedStatus -- test bits in saved status	      */
+/*								      */
+/*  oldstatus is the status word to be tested			      */
+/*  mask indicates the bits to be tested (the oldstatus bits that     */
+/*    correspond to each 1 bit in the mask are tested)		      */
+/*  returns 1 if any of the tested bits are 1, or 0 otherwise	      */
+/*								      */
+/* No error is possible.					      */
+/* ------------------------------------------------------------------ */
+uInt decContextTestSavedStatus(uInt oldstatus, uInt mask) {
+  return (oldstatus&mask)!=0;
+  } /* decContextTestSavedStatus */
+
+/* ------------------------------------------------------------------ */
+/* decContextTestStatus -- test bits in current status		      */
+/*								      */
+/*  context is the context structure to be updated		      */
+/*  mask indicates the bits to be tested (the status bits that	      */
+/*    correspond to each 1 bit in the mask are tested)		      */
+/*  returns 1 if any of the tested bits are 1, or 0 otherwise	      */
+/*								      */
+/* No error is possible.					      */
+/* ------------------------------------------------------------------ */
+uInt decContextTestStatus(decContext *context, uInt mask) {
+  return (context->status&mask)!=0;
+  } /* decContextTestStatus */
+
+/* ------------------------------------------------------------------ */
+/* decContextZeroStatus -- clear all status bits		      */
+/*								      */
+/*  context is the context structure to be updated		      */
+/*  returns context						      */
+/*								      */
+/* No error is possible.					      */
+/* ------------------------------------------------------------------ */
+decContext *decContextZeroStatus(decContext *context) {
+  context->status=0;
+  return context;
+  } /* decContextZeroStatus */
+