/* ------------------------------------------------------------------ */ /* Decimal Context module */ /* ------------------------------------------------------------------ */ /* Copyright (c) IBM Corporation, 2000, 2005. All rights reserved. */ /* */ /* This software is made available under the terms of the */ /* ICU License -- ICU 1.8.1 and later. */ /* */ /* The description and User's Guide ("The decNumber C Library") for */ /* this software is called decNumber.pdf. This document is */ /* available, together with arithmetic and format specifications, */ /* testcases, and Web links, at: http://www2.hursley.ibm.com/decimal */ /* */ /* Please send comments, suggestions, and corrections to the author: */ /* mfc@uk.ibm.com */ /* Mike Cowlishaw, IBM Fellow */ /* IBM UK, PO Box 31, Birmingham Road, Warwick CV34 5JL, UK */ /* ------------------------------------------------------------------ */ /* This module comprises the routines for handling arithmetic */ /* context structures. */ /* ------------------------------------------------------------------ */ #include // for strcmp #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