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/* ------------------------------------------------------------------ */
/* Decimal Context module header */
/* ------------------------------------------------------------------ */
/* 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 */
/* ------------------------------------------------------------------ */
/* */
/* Context must always be set correctly: */
/* */
/* digits -- must be in the range 1 through 999999999 */
/* emax -- must be in the range 0 through 999999999 */
/* emin -- must be in the range 0 through -999999999 */
/* round -- must be one of the enumerated rounding modes */
/* traps -- only defined bits may be set */
/* status -- [any bits may be cleared, but not set, by user] */
/* clamp -- must be either 0 or 1 */
/* extended -- must be either 0 or 1 [present only if DECSUBSET] */
/* */
/* ------------------------------------------------------------------ */
#if !defined(DECCONTEXT)
#define DECCONTEXT
#define DECCNAME "decContext" /* Short name */
#define DECCFULLNAME "Decimal Context Descriptor" /* Verbose name */
#define DECCAUTHOR "Mike Cowlishaw" /* Who to blame */
#if !defined(int32_t)
#include <hstdint.h> // C99 standard integers
#endif
#include <signal.h> // for traps
/* Conditional code flag -- set this to 0 for best performance */
#define DECSUBSET 0 // 1=enable subset arithmetic
/* Context for operations, with associated constants */
enum rounding {
DEC_ROUND_CEILING, // round towards +infinity
DEC_ROUND_UP, // round away from 0
DEC_ROUND_HALF_UP, // 0.5 rounds up
DEC_ROUND_HALF_EVEN, // 0.5 rounds to nearest even
DEC_ROUND_HALF_DOWN, // 0.5 rounds down
DEC_ROUND_DOWN, // round towards 0 (truncate)
DEC_ROUND_FLOOR, // round towards -infinity
DEC_ROUND_MAX // enum must be less than this
};
typedef struct {
int32_t digits; // working precision
int32_t emax; // maximum positive exponent
int32_t emin; // minimum negative exponent
enum rounding round; // rounding mode
uint32_t traps; // trap-enabler flags
uint32_t status; // status flags
uint8_t clamp; // flag: apply IEEE exponent clamp
#if DECSUBSET
uint8_t extended; // flag: special-values allowed
#endif
} decContext;
/* Maxima and Minima */
#define DEC_MAX_DIGITS 999999999
#define DEC_MIN_DIGITS 1
#define DEC_MAX_EMAX 999999999
#define DEC_MIN_EMAX 0
#define DEC_MAX_EMIN 0
#define DEC_MIN_EMIN -999999999
#define DEC_MAX_MATH 999999 // max emax, etc., for math functions
/* Trap-enabler and Status flags (exceptional conditions), and their names */
// Top byte is reserved for internal use
#define DEC_Conversion_syntax 0x00000001
#define DEC_Division_by_zero 0x00000002
#define DEC_Division_impossible 0x00000004
#define DEC_Division_undefined 0x00000008
#define DEC_Insufficient_storage 0x00000010 // [used if malloc fails]
#define DEC_Inexact 0x00000020
#define DEC_Invalid_context 0x00000040
#define DEC_Invalid_operation 0x00000080
#if DECSUBSET
#define DEC_Lost_digits 0x00000100
#endif
#define DEC_Overflow 0x00000200
#define DEC_Clamped 0x00000400
#define DEC_Rounded 0x00000800
#define DEC_Subnormal 0x00001000
#define DEC_Underflow 0x00002000
/* IEEE 854 groupings for the flags */
// [DEC_Clamped, DEC_Lost_digits, DEC_Rounded, and DEC_Subnormal are
// not in IEEE 854]
#define DEC_IEEE_854_Division_by_zero (DEC_Division_by_zero)
#if DECSUBSET
#define DEC_IEEE_854_Inexact (DEC_Inexact | DEC_Lost_digits)
#else
#define DEC_IEEE_854_Inexact (DEC_Inexact)
#endif
#define DEC_IEEE_854_Invalid_operation (DEC_Conversion_syntax | \
DEC_Division_impossible | \
DEC_Division_undefined | \
DEC_Insufficient_storage | \
DEC_Invalid_context | \
DEC_Invalid_operation)
#define DEC_IEEE_854_Overflow (DEC_Overflow)
#define DEC_IEEE_854_Underflow (DEC_Underflow)
// flags which are normally errors (results are qNaN, infinite, or 0)
#define DEC_Errors (DEC_IEEE_854_Division_by_zero | \
DEC_IEEE_854_Invalid_operation | \
DEC_IEEE_854_Overflow | DEC_IEEE_854_Underflow)
// flags which cause a result to become qNaN
#define DEC_NaNs DEC_IEEE_854_Invalid_operation
// flags which are normally for information only (have finite results)
#if DECSUBSET
#define DEC_Information (DEC_Clamped | DEC_Rounded | DEC_Inexact \
| DEC_Lost_digits)
#else
#define DEC_Information (DEC_Clamped | DEC_Rounded | DEC_Inexact)
#endif
// name strings for the exceptional conditions
#define DEC_Condition_CS "Conversion syntax"
#define DEC_Condition_DZ "Division by zero"
#define DEC_Condition_DI "Division impossible"
#define DEC_Condition_DU "Division undefined"
#define DEC_Condition_IE "Inexact"
#define DEC_Condition_IS "Insufficient storage"
#define DEC_Condition_IC "Invalid context"
#define DEC_Condition_IO "Invalid operation"
#if DECSUBSET
#define DEC_Condition_LD "Lost digits"
#endif
#define DEC_Condition_OV "Overflow"
#define DEC_Condition_PA "Clamped"
#define DEC_Condition_RO "Rounded"
#define DEC_Condition_SU "Subnormal"
#define DEC_Condition_UN "Underflow"
#define DEC_Condition_ZE "No status"
#define DEC_Condition_MU "Multiple status"
#define DEC_Condition_Length 21 // length of the longest string,
// including terminator
/* Initialization descriptors, used by decContextDefault */
#define DEC_INIT_BASE 0
#define DEC_INIT_DECIMAL32 32
#define DEC_INIT_DECIMAL64 64
#define DEC_INIT_DECIMAL128 128
/* decContext routines */
decContext * decContextDefault(decContext *, int32_t);
decContext * decContextSetStatus(decContext *, uint32_t);
const char * decContextStatusToString(const decContext *);
decContext * decContextSetStatusFromString(decContext *, const char *);
#endif
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