338 lines
13 KiB
C
338 lines
13 KiB
C
/* Decimal 32-bit format 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.
|
|
|
|
In addition to the permissions in the GNU General Public License,
|
|
the Free Software Foundation gives you unlimited permission to link
|
|
the compiled version of this file into combinations with other
|
|
programs, and to distribute those combinations without any
|
|
restriction coming from the use of this file. (The General Public
|
|
License restrictions do apply in other respects; for example, they
|
|
cover modification of the file, and distribution when not linked
|
|
into a combine executable.)
|
|
|
|
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 comprises the routines for decimal32 format numbers. */
|
|
/* Conversions are supplied to and from decNumber and String. */
|
|
/* */
|
|
/* No arithmetic routines are included; decNumber provides these. */
|
|
/* */
|
|
/* Error handling is the same as decNumber (qv.). */
|
|
/* ------------------------------------------------------------------ */
|
|
#include <string.h> /* [for memset/memcpy] */
|
|
#include <stdio.h> /* [for printf] */
|
|
|
|
#define DECNUMDIGITS 7 /* we need decNumbers with space for 7 */
|
|
#include "config.h"
|
|
#include "decNumber.h" /* base number library */
|
|
#include "decNumberLocal.h" /* decNumber local types, etc. */
|
|
#include "decimal32.h" /* our primary include */
|
|
#include "decUtility.h" /* utility routines */
|
|
|
|
#if DECTRACE || DECCHECK
|
|
void decimal32Show (const decimal32 *); /* for debug */
|
|
void decNumberShow (const decNumber *); /* .. */
|
|
#endif
|
|
|
|
/* Useful macro */
|
|
/* Clear a structure (e.g., a decNumber) */
|
|
#define DEC_clear(d) memset(d, 0, sizeof(*d))
|
|
|
|
/* ------------------------------------------------------------------ */
|
|
/* decimal32FromNumber -- convert decNumber to decimal32 */
|
|
/* */
|
|
/* ds is the target decimal32 */
|
|
/* dn is the source number (assumed valid) */
|
|
/* set is the context, used only for reporting errors */
|
|
/* */
|
|
/* The set argument is used only for status reporting and for the */
|
|
/* rounding mode (used if the coefficient is more than DECIMAL32_Pmax */
|
|
/* digits or an overflow is detected). If the exponent is out of the */
|
|
/* valid range then Overflow or Underflow will be raised. */
|
|
/* After Underflow a subnormal result is possible. */
|
|
/* */
|
|
/* DEC_Clamped is set if the number has to be 'folded down' to fit, */
|
|
/* by reducing its exponent and multiplying the coefficient by a */
|
|
/* power of ten, or if the exponent on a zero had to be clamped. */
|
|
/* ------------------------------------------------------------------ */
|
|
decimal32 *
|
|
decimal32FromNumber (decimal32 * d32, const decNumber * dn, decContext * set)
|
|
{
|
|
uInt status = 0; /* status accumulator */
|
|
Int pad = 0; /* coefficient pad digits */
|
|
decNumber dw; /* work */
|
|
decContext dc; /* .. */
|
|
uByte isneg = dn->bits & DECNEG; /* non-0 if original sign set */
|
|
uInt comb, exp; /* work */
|
|
|
|
/* If the number is finite, and has too many digits, or the exponent */
|
|
/* could be out of range then we reduce the number under the */
|
|
/* appropriate constraints */
|
|
if (!(dn->bits & DECSPECIAL))
|
|
{ /* not a special value */
|
|
Int ae = dn->exponent + dn->digits - 1; /* adjusted exponent */
|
|
if (dn->digits > DECIMAL32_Pmax /* too many digits */
|
|
|| ae > DECIMAL32_Emax /* likely overflow */
|
|
|| ae < DECIMAL32_Emin)
|
|
{ /* likely underflow */
|
|
decContextDefault (&dc, DEC_INIT_DECIMAL32); /* [no traps] */
|
|
dc.round = set->round; /* use supplied rounding */
|
|
decNumberPlus (&dw, dn, &dc); /* (round and check) */
|
|
/* [this changes -0 to 0, but it will be restored below] */
|
|
status |= dc.status; /* save status */
|
|
dn = &dw; /* use the work number */
|
|
}
|
|
/* [this could have pushed number to Infinity or zero, so this */
|
|
/* rounding must be done before we generate the decimal32] */
|
|
}
|
|
|
|
DEC_clear (d32); /* clean the target */
|
|
if (dn->bits & DECSPECIAL)
|
|
{ /* a special value */
|
|
uByte top; /* work */
|
|
if (dn->bits & DECINF)
|
|
top = DECIMAL_Inf;
|
|
else
|
|
{ /* sNaN or qNaN */
|
|
if ((*dn->lsu != 0 || dn->digits > 1) /* non-zero coefficient */
|
|
&& (dn->digits < DECIMAL32_Pmax))
|
|
{ /* coefficient fits */
|
|
decDensePackCoeff (dn, d32->bytes, sizeof (d32->bytes), 0);
|
|
}
|
|
if (dn->bits & DECNAN)
|
|
top = DECIMAL_NaN;
|
|
else
|
|
top = DECIMAL_sNaN;
|
|
}
|
|
d32->bytes[0] = top;
|
|
}
|
|
else if (decNumberIsZero (dn))
|
|
{ /* a zero */
|
|
/* set and clamp exponent */
|
|
if (dn->exponent < -DECIMAL32_Bias)
|
|
{
|
|
exp = 0;
|
|
status |= DEC_Clamped;
|
|
}
|
|
else
|
|
{
|
|
exp = dn->exponent + DECIMAL32_Bias; /* bias exponent */
|
|
if (exp > DECIMAL32_Ehigh)
|
|
{ /* top clamp */
|
|
exp = DECIMAL32_Ehigh;
|
|
status |= DEC_Clamped;
|
|
}
|
|
}
|
|
comb = (exp >> 3) & 0x18; /* combination field */
|
|
d32->bytes[0] = (uByte) (comb << 2);
|
|
exp &= 0x3f; /* remaining exponent bits */
|
|
decimal32SetExpCon (d32, exp);
|
|
}
|
|
else
|
|
{ /* non-zero finite number */
|
|
uInt msd; /* work */
|
|
|
|
/* we have a dn that fits, but it may need to be padded */
|
|
exp = (uInt) (dn->exponent + DECIMAL32_Bias); /* bias exponent */
|
|
|
|
if (exp > DECIMAL32_Ehigh)
|
|
{ /* fold-down case */
|
|
pad = exp - DECIMAL32_Ehigh;
|
|
exp = DECIMAL32_Ehigh; /* [to maximum] */
|
|
status |= DEC_Clamped;
|
|
}
|
|
|
|
decDensePackCoeff (dn, d32->bytes, sizeof (d32->bytes), pad);
|
|
|
|
/* save and clear the top digit */
|
|
msd = ((unsigned) d32->bytes[1] >> 4);
|
|
d32->bytes[1] &= 0x0f;
|
|
/* create the combination field */
|
|
if (msd >= 8)
|
|
comb = 0x18 | (msd & 0x01) | ((exp >> 5) & 0x06);
|
|
else
|
|
comb = (msd & 0x07) | ((exp >> 3) & 0x18);
|
|
d32->bytes[0] = (uByte) (comb << 2);
|
|
exp &= 0x3f; /* remaining exponent bits */
|
|
decimal32SetExpCon (d32, exp);
|
|
}
|
|
|
|
if (isneg)
|
|
decimal32SetSign (d32, 1);
|
|
if (status != 0)
|
|
decContextSetStatus (set, status); /* pass on status */
|
|
|
|
/*decimal32Show(d32); */
|
|
return d32;
|
|
}
|
|
|
|
/* ------------------------------------------------------------------ */
|
|
/* decimal32ToNumber -- convert decimal32 to decNumber */
|
|
/* d32 is the source decimal32 */
|
|
/* dn is the target number, with appropriate space */
|
|
/* No error is possible. */
|
|
/* ------------------------------------------------------------------ */
|
|
decNumber *
|
|
decimal32ToNumber (const decimal32 * d32, decNumber * dn)
|
|
{
|
|
uInt msd; /* coefficient MSD */
|
|
decimal32 wk; /* working copy, if needed */
|
|
uInt top = d32->bytes[0] & 0x7f; /* top byte, less sign bit */
|
|
decNumberZero (dn); /* clean target */
|
|
/* set the sign if negative */
|
|
if (decimal32Sign (d32))
|
|
dn->bits = DECNEG;
|
|
|
|
if (top >= 0x78)
|
|
{ /* is a special */
|
|
if ((top & 0x7c) == (DECIMAL_Inf & 0x7c))
|
|
dn->bits |= DECINF;
|
|
else if ((top & 0x7e) == (DECIMAL_NaN & 0x7e))
|
|
dn->bits |= DECNAN;
|
|
else
|
|
dn->bits |= DECSNAN;
|
|
msd = 0; /* no top digit */
|
|
}
|
|
else
|
|
{ /* have a finite number */
|
|
uInt comb = top >> 2; /* combination field */
|
|
uInt exp; /* working exponent */
|
|
|
|
if (comb >= 0x18)
|
|
{
|
|
msd = 8 + (comb & 0x01);
|
|
exp = (comb & 0x06) << 5; /* MSBs */
|
|
}
|
|
else
|
|
{
|
|
msd = comb & 0x07;
|
|
exp = (comb & 0x18) << 3;
|
|
}
|
|
dn->exponent = exp + decimal32ExpCon (d32) - DECIMAL32_Bias; /* remove bias */
|
|
}
|
|
|
|
/* get the coefficient, unless infinite */
|
|
if (!(dn->bits & DECINF))
|
|
{
|
|
Int bunches = DECIMAL32_Pmax / 3; /* coefficient full bunches to convert */
|
|
Int odd = 0; /* assume MSD is 0 (no odd bunch) */
|
|
if (msd != 0)
|
|
{ /* coefficient has leading non-0 digit */
|
|
/* make a copy of the decimal32, with an extra bunch which has */
|
|
/* the top digit ready for conversion */
|
|
wk = *d32; /* take a copy */
|
|
wk.bytes[0] = 0; /* clear all but coecon */
|
|
wk.bytes[1] &= 0x0f; /* .. */
|
|
wk.bytes[1] |= (msd << 4); /* and prefix MSD */
|
|
odd++; /* indicate the extra */
|
|
d32 = &wk; /* use the work copy */
|
|
}
|
|
decDenseUnpackCoeff (d32->bytes, sizeof (d32->bytes), dn, bunches, odd);
|
|
}
|
|
return dn;
|
|
}
|
|
|
|
/* ------------------------------------------------------------------ */
|
|
/* to-scientific-string -- conversion to numeric string */
|
|
/* to-engineering-string -- conversion to numeric string */
|
|
/* */
|
|
/* decimal32ToString(d32, string); */
|
|
/* decimal32ToEngString(d32, string); */
|
|
/* */
|
|
/* d32 is the decimal32 format number to convert */
|
|
/* string is the string where the result will be laid out */
|
|
/* */
|
|
/* string must be at least 24 characters */
|
|
/* */
|
|
/* No error is possible, and no status can be set. */
|
|
/* ------------------------------------------------------------------ */
|
|
char *
|
|
decimal32ToString (const decimal32 * d32, char *string)
|
|
{
|
|
decNumber dn; /* work */
|
|
decimal32ToNumber (d32, &dn);
|
|
decNumberToString (&dn, string);
|
|
return string;
|
|
}
|
|
|
|
char *
|
|
decimal32ToEngString (const decimal32 * d32, char *string)
|
|
{
|
|
decNumber dn; /* work */
|
|
decimal32ToNumber (d32, &dn);
|
|
decNumberToEngString (&dn, string);
|
|
return string;
|
|
}
|
|
|
|
/* ------------------------------------------------------------------ */
|
|
/* to-number -- conversion from numeric string */
|
|
/* */
|
|
/* decimal32FromString(result, string, set); */
|
|
/* */
|
|
/* result is the decimal32 format number which gets the result of */
|
|
/* the conversion */
|
|
/* *string is the character string which should contain a valid */
|
|
/* number (which may be a special value) */
|
|
/* set is the context */
|
|
/* */
|
|
/* The context is supplied to this routine is used for error handling */
|
|
/* (setting of status and traps) and for the rounding mode, only. */
|
|
/* If an error occurs, the result will be a valid decimal32 NaN. */
|
|
/* ------------------------------------------------------------------ */
|
|
decimal32 *
|
|
decimal32FromString (decimal32 * result, const char *string, decContext * set)
|
|
{
|
|
decContext dc; /* work */
|
|
decNumber dn; /* .. */
|
|
|
|
decContextDefault (&dc, DEC_INIT_DECIMAL32); /* no traps, please */
|
|
dc.round = set->round; /* use supplied rounding */
|
|
|
|
decNumberFromString (&dn, string, &dc); /* will round if needed */
|
|
decimal32FromNumber (result, &dn, &dc);
|
|
if (dc.status != 0)
|
|
{ /* something happened */
|
|
decContextSetStatus (set, dc.status); /* .. pass it on */
|
|
}
|
|
return result;
|
|
}
|
|
|
|
#if DECTRACE || DECCHECK
|
|
/* ------------------------------------------------------------------ */
|
|
/* decimal32Show -- display a single in hexadecimal [debug aid] */
|
|
/* d32 -- the number to show */
|
|
/* ------------------------------------------------------------------ */
|
|
/* Also shows sign/cob/expconfields extracted */
|
|
void
|
|
decimal32Show (const decimal32 * d32)
|
|
{
|
|
char buf[DECIMAL32_Bytes * 2 + 1];
|
|
Int i, j;
|
|
j = 0;
|
|
for (i = 0; i < DECIMAL32_Bytes; i++)
|
|
{
|
|
sprintf (&buf[j], "%02x", d32->bytes[i]);
|
|
j = j + 2;
|
|
}
|
|
printf (" D32> %s [S:%d Cb:%02x E:%d]\n", buf,
|
|
decimal32Sign (d32), decimal32Comb (d32), decimal32ExpCon (d32));
|
|
}
|
|
#endif
|