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Diffstat (limited to 'libdecnumber/decContext.c')
| -rw-r--r-- | libdecnumber/decContext.c | 450 |
1 files changed, 450 insertions, 0 deletions
diff --git a/libdecnumber/decContext.c b/libdecnumber/decContext.c new file mode 100644 index 000000000..aa8195928 --- /dev/null +++ b/libdecnumber/decContext.c @@ -0,0 +1,450 @@ +/* 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 */ +#ifdef DECCHECK +#include <stdio.h> /* for printf if DECCHECK */ +#endif +#include "dconfig.h" /* for GCC definitions */ +#include "decContext.h" /* context and base types */ +#include "decNumberLocal.h" /* decNumber local types, etc. */ + +/* compile-time endian tester [assumes sizeof(Int)>1] */ +static const Int mfcone=1; /* constant 1 */ +static const Flag *mfctop=(const Flag *)&mfcone; /* -> top byte */ +#define LITEND *mfctop /* named flag; 1=little-endian */ + +/* ------------------------------------------------------------------ */ +/* 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 754 defaults, 32-bit */ +/* DEC_INIT_DECIMAL64 -- select IEEE 754 defaults, 64-bit */ +/* DEC_INIT_DECIMAL128 -- select IEEE 754 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 */ + +/* ------------------------------------------------------------------ */ +/* 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 */ + +/* ------------------------------------------------------------------ */ +/* decContextTestEndian -- test whether DECLITEND is set correctly */ +/* */ +/* quiet is 1 to suppress message; 0 otherwise */ +/* returns 0 if DECLITEND is correct */ +/* 1 if DECLITEND is incorrect and should be 1 */ +/* -1 if DECLITEND is incorrect and should be 0 */ +/* */ +/* A message is displayed if the return value is not 0 and quiet==0. */ +/* */ +/* No error is possible. */ +/* ------------------------------------------------------------------ */ +Int decContextTestEndian(Flag quiet) { + Int res=0; /* optimist */ + uInt dle=(uInt)DECLITEND; /* unsign */ + if (dle>1) dle=1; /* ensure 0 or 1 */ + + if (LITEND!=DECLITEND) { + if (!quiet) { +#if DECCHECK + 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 + } + res=(Int)LITEND-dle; + } + return res; + } /* decContextTestEndian */ + +/* ------------------------------------------------------------------ */ +/* 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 */ + |