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decCommon.c
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decCommon.c
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/* Common code for fixed-size types in the decNumber C Library.
Copyright (C) 2007-2024 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/>. */
/* ------------------------------------------------------------------ */
/* decCommon.c -- common code for all three fixed-size types */
/* ------------------------------------------------------------------ */
/* This module comprises code that is shared between all the formats */
/* (decSingle, decDouble, and decQuad); it includes set and extract */
/* of format components, widening, narrowing, and string conversions. */
/* */
/* Unlike decNumber, parameterization takes place at compile time */
/* rather than at runtime. The parameters are set in the decDouble.c */
/* (etc.) files, which then include this one to produce the compiled */
/* code. The functions here, therefore, are code shared between */
/* multiple formats. */
/* ------------------------------------------------------------------ */
/* Names here refer to decFloat rather than to decDouble, etc., and */
/* the functions are in strict alphabetical order. */
/* Constants, tables, and debug function(s) are included only for QUAD */
/* (which will always be compiled if DOUBLE or SINGLE are used). */
/* */
/* Whenever a decContext is used, only the status may be set (using */
/* OR) or the rounding mode read; all other fields are ignored and */
/* untouched. */
#include "decCommonSymbols.h"
/* names for simpler testing and default context */
#if DECPMAX==7
#define SINGLE 1
#define DOUBLE 0
#define QUAD 0
#define DEFCONTEXT DEC_INIT_DECIMAL32
#elif DECPMAX==16
#define SINGLE 0
#define DOUBLE 1
#define QUAD 0
#define DEFCONTEXT DEC_INIT_DECIMAL64
#elif DECPMAX==34
#define SINGLE 0
#define DOUBLE 0
#define QUAD 1
#define DEFCONTEXT DEC_INIT_DECIMAL128
#else
#error Unexpected DECPMAX value
#endif
/* Assertions */
#if DECPMAX!=7 && DECPMAX!=16 && DECPMAX!=34
#error Unexpected Pmax (DECPMAX) value for this module
#endif
/* Assert facts about digit characters, etc. */
#if ('9'&0x0f)!=9
#error This module assumes characters are of the form 0b....nnnn
/* where .... are don't care 4 bits and nnnn is 0000 through 1001 */
#endif
#if ('9'&0xf0)==('.'&0xf0)
#error This module assumes '.' has a different mask than a digit
#endif
/* Assert ToString lay-out conditions */
#if DECSTRING<DECPMAX+9
#error ToString needs at least 8 characters for lead-in and dot
#endif
#if DECPMAX+DECEMAXD+5 > DECSTRING
#error Exponent form can be too long for ToString to lay out safely
#endif
#if DECEMAXD > 4
#error Exponent form is too long for ToString to lay out
/* Note: code for up to 9 digits exists in archives [decOct] */
#endif
/* Private functions used here and possibly in decBasic.c, etc. */
static decFloat * decFinalize(decFloat *, bcdnum *, decContext *);
static Flag decBiStr(const char *, const char *, const char *);
/* Macros and private tables; those which are not format-dependent */
/* are only included if decQuad is being built. */
/* ------------------------------------------------------------------ */
/* Combination field lookup tables (uInts to save measurable work) */
/* */
/* DECCOMBEXP - 2 most-significant-bits of exponent (00, 01, or */
/* 10), shifted left for format, or DECFLOAT_Inf/NaN */
/* DECCOMBWEXP - The same, for the next-wider format (unless QUAD) */
/* DECCOMBMSD - 4-bit most-significant-digit */
/* [0 if the index is a special (Infinity or NaN)] */
/* DECCOMBFROM - 5-bit combination field from EXP top bits and MSD */
/* (placed in uInt so no shift is needed) */
/* */
/* DECCOMBEXP, DECCOMBWEXP, and DECCOMBMSD are indexed by the sign */
/* and 5-bit combination field (0-63, the second half of the table */
/* identical to the first half) */
/* DECCOMBFROM is indexed by expTopTwoBits*16 + msd */
/* */
/* DECCOMBMSD and DECCOMBFROM are not format-dependent and so are */
/* only included once, when QUAD is being built */
/* ------------------------------------------------------------------ */
static const uInt DECCOMBEXP[64]={
0, 0, 0, 0, 0, 0, 0, 0,
1<<DECECONL, 1<<DECECONL, 1<<DECECONL, 1<<DECECONL,
1<<DECECONL, 1<<DECECONL, 1<<DECECONL, 1<<DECECONL,
2<<DECECONL, 2<<DECECONL, 2<<DECECONL, 2<<DECECONL,
2<<DECECONL, 2<<DECECONL, 2<<DECECONL, 2<<DECECONL,
0, 0, 1<<DECECONL, 1<<DECECONL,
2<<DECECONL, 2<<DECECONL, DECFLOAT_Inf, DECFLOAT_NaN,
0, 0, 0, 0, 0, 0, 0, 0,
1<<DECECONL, 1<<DECECONL, 1<<DECECONL, 1<<DECECONL,
1<<DECECONL, 1<<DECECONL, 1<<DECECONL, 1<<DECECONL,
2<<DECECONL, 2<<DECECONL, 2<<DECECONL, 2<<DECECONL,
2<<DECECONL, 2<<DECECONL, 2<<DECECONL, 2<<DECECONL,
0, 0, 1<<DECECONL, 1<<DECECONL,
2<<DECECONL, 2<<DECECONL, DECFLOAT_Inf, DECFLOAT_NaN};
#if !QUAD
static const uInt DECCOMBWEXP[64]={
0, 0, 0, 0, 0, 0, 0, 0,
1<<DECWECONL, 1<<DECWECONL, 1<<DECWECONL, 1<<DECWECONL,
1<<DECWECONL, 1<<DECWECONL, 1<<DECWECONL, 1<<DECWECONL,
2<<DECWECONL, 2<<DECWECONL, 2<<DECWECONL, 2<<DECWECONL,
2<<DECWECONL, 2<<DECWECONL, 2<<DECWECONL, 2<<DECWECONL,
0, 0, 1<<DECWECONL, 1<<DECWECONL,
2<<DECWECONL, 2<<DECWECONL, DECFLOAT_Inf, DECFLOAT_NaN,
0, 0, 0, 0, 0, 0, 0, 0,
1<<DECWECONL, 1<<DECWECONL, 1<<DECWECONL, 1<<DECWECONL,
1<<DECWECONL, 1<<DECWECONL, 1<<DECWECONL, 1<<DECWECONL,
2<<DECWECONL, 2<<DECWECONL, 2<<DECWECONL, 2<<DECWECONL,
2<<DECWECONL, 2<<DECWECONL, 2<<DECWECONL, 2<<DECWECONL,
0, 0, 1<<DECWECONL, 1<<DECWECONL,
2<<DECWECONL, 2<<DECWECONL, DECFLOAT_Inf, DECFLOAT_NaN};
#endif
#if QUAD
const uInt DECCOMBMSD[64]={
0, 1, 2, 3, 4, 5, 6, 7, 0, 1, 2, 3, 4, 5, 6, 7,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 8, 9, 8, 9, 0, 0,
0, 1, 2, 3, 4, 5, 6, 7, 0, 1, 2, 3, 4, 5, 6, 7,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 8, 9, 8, 9, 0, 0};
const uInt DECCOMBFROM[48]={
0x00000000, 0x04000000, 0x08000000, 0x0C000000, 0x10000000, 0x14000000,
0x18000000, 0x1C000000, 0x60000000, 0x64000000, 0x00000000, 0x00000000,
0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x20000000, 0x24000000,
0x28000000, 0x2C000000, 0x30000000, 0x34000000, 0x38000000, 0x3C000000,
0x68000000, 0x6C000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
0x00000000, 0x00000000, 0x40000000, 0x44000000, 0x48000000, 0x4C000000,
0x50000000, 0x54000000, 0x58000000, 0x5C000000, 0x70000000, 0x74000000,
0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000};
/* ------------------------------------------------------------------ */
/* Request and include the tables to use for conversions */
/* ------------------------------------------------------------------ */
#define DEC_BCD2DPD 1 /* 0-0x999 -> DPD */
#define DEC_BIN2DPD 1 /* 0-999 -> DPD */
#define DEC_BIN2BCD8 1 /* 0-999 -> ddd, len */
#define DEC_DPD2BCD8 1 /* DPD -> ddd, len */
#define DEC_DPD2BIN 1 /* DPD -> 0-999 */
#define DEC_DPD2BINK 1 /* DPD -> 0-999000 */
#define DEC_DPD2BINM 1 /* DPD -> 0-999000000 */
#include "decDPD.h" /* source of the lookup tables */
#endif
/* ----------------------------------------------------------------- */
/* decBiStr -- compare string with pairwise options */
/* */
/* targ is the string to compare */
/* str1 is one of the strings to compare against (length may be 0) */
/* str2 is the other; it must be the same length as str1 */
/* */
/* returns 1 if strings compare equal, (that is, targ is the same */
/* length as str1 and str2, and each character of targ is in one */
/* of str1 or str2 in the corresponding position), or 0 otherwise */
/* */
/* This is used for generic caseless compare, including the awkward */
/* case of the Turkish dotted and dotless Is. Use as (for example): */
/* if (decBiStr(test, "mike", "MIKE")) ... */
/* ----------------------------------------------------------------- */
static Flag decBiStr(const char *targ, const char *str1, const char *str2) {
for (;;targ++, str1++, str2++) {
if (*targ!=*str1 && *targ!=*str2) return 0;
/* *targ has a match in one (or both, if terminator) */
if (*targ=='\0') break;
} /* forever */
return 1;
} /* decBiStr */
/* ------------------------------------------------------------------ */
/* decFinalize -- adjust and store a final result */
/* */
/* df is the decFloat format number which gets the final result */
/* num is the descriptor of the number to be checked and encoded */
/* [its values, including the coefficient, may be modified] */
/* set is the context to use */
/* returns df */
/* */
/* The num descriptor may point to a bcd8 string of any length; this */
/* string may have leading insignificant zeros. If it has more than */
/* DECPMAX digits then the final digit can be a round-for-reround */
/* digit (i.e., it may include a sticky bit residue). */
/* */
/* The exponent (q) may be one of the codes for a special value and */
/* can be up to 999999999 for conversion from string. */
/* */
/* No error is possible, but Inexact, Underflow, and/or Overflow may */
/* be set. */
/* ------------------------------------------------------------------ */
/* Constant whose size varies with format; also the check for surprises */
static uByte allnines[DECPMAX]=
#if SINGLE
{9, 9, 9, 9, 9, 9, 9};
#elif DOUBLE
{9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9};
#elif QUAD
{9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9};
#endif
static decFloat * decFinalize(decFloat *df, bcdnum *num,
decContext *set) {
uByte *ub; /* work */
uInt dpd; /* .. */
uInt uiwork; /* for macros */
uByte *umsd=num->msd; /* local copy */
uByte *ulsd=num->lsd; /* .. */
uInt encode; /* encoding accumulator */
Int length; /* coefficient length */
#if DECCHECK
Int clen=ulsd-umsd+1;
#if QUAD
#define COEXTRA 2 /* extra-long coefficent */
#else
#define COEXTRA 0
#endif
if (clen<1 || clen>DECPMAX*3+2+COEXTRA)
printf("decFinalize: suspect coefficient [length=%ld]\n", (LI)clen);
if (num->sign!=0 && num->sign!=DECFLOAT_Sign)
printf("decFinalize: bad sign [%08lx]\n", (LI)num->sign);
if (!EXPISSPECIAL(num->exponent)
&& (num->exponent>1999999999 || num->exponent<-1999999999))
printf("decFinalize: improbable exponent [%ld]\n", (LI)num->exponent);
/* decShowNum(num, "final"); */
#endif
/* A special will have an 'exponent' which is very positive and a */
/* coefficient < DECPMAX */
length=(uInt)(ulsd-umsd+1); /* coefficient length */
if (!NUMISSPECIAL(num)) {
Int drop; /* digits to be dropped */
/* skip leading insignificant zeros to calculate an exact length */
/* [this is quite expensive] */
if (*umsd==0) {
for (; umsd+3<ulsd && UBTOUI(umsd)==0;) umsd+=4;
for (; *umsd==0 && umsd<ulsd;) umsd++;
length=ulsd-umsd+1; /* recalculate */
}
drop=MAXI(length-DECPMAX, DECQTINY-num->exponent);
/* drop can now be > digits for bottom-clamp (subnormal) cases */
if (drop>0) { /* rounding needed */
/* (decFloatQuantize has very similar code to this, so any */
/* changes may need to be made there, too) */
uByte *roundat; /* -> re-round digit */
uByte reround; /* reround value */
/* printf("Rounding; drop=%ld\n", (LI)drop); */
num->exponent+=drop; /* always update exponent */
/* Three cases here: */
/* 1. new LSD is in coefficient (almost always) */
/* 2. new LSD is digit to left of coefficient (so MSD is */
/* round-for-reround digit) */
/* 3. new LSD is to left of case 2 (whole coefficient is sticky) */
/* [duplicate check-stickies code to save a test] */
/* [by-digit check for stickies as runs of zeros are rare] */
if (drop<length) { /* NB lengths not addresses */
roundat=umsd+length-drop;
reround=*roundat;
for (ub=roundat+1; ub<=ulsd; ub++) {
if (*ub!=0) { /* non-zero to be discarded */
reround=DECSTICKYTAB[reround]; /* apply sticky bit */
break; /* [remainder don't-care] */
}
} /* check stickies */
ulsd=roundat-1; /* new LSD */
}
else { /* edge case */
if (drop==length) {
roundat=umsd;
reround=*roundat;
}
else {
roundat=umsd-1;
reround=0;
}
for (ub=roundat+1; ub<=ulsd; ub++) {
if (*ub!=0) { /* non-zero to be discarded */
reround=DECSTICKYTAB[reround]; /* apply sticky bit */
break; /* [remainder don't-care] */
}
} /* check stickies */
*umsd=0; /* coefficient is a 0 */
ulsd=umsd; /* .. */
}
if (reround!=0) { /* discarding non-zero */
uInt bump=0;
set->status|=DEC_Inexact;
/* if adjusted exponent [exp+digits-1] is < EMIN then num is */
/* subnormal -- so raise Underflow */
if (num->exponent<DECEMIN && (num->exponent+(ulsd-umsd+1)-1)<DECEMIN)
set->status|=DEC_Underflow;
/* next decide whether increment of the coefficient is needed */
if (set->round==DEC_ROUND_HALF_EVEN) { /* fastpath slowest case */
if (reround>5) bump=1; /* >0.5 goes up */
else if (reround==5) /* exactly 0.5000 .. */
bump=*ulsd & 0x01; /* .. up iff [new] lsd is odd */
} /* r-h-e */
else switch (set->round) {
case DEC_ROUND_DOWN: {
/* no change */
break;} /* r-d */
case DEC_ROUND_HALF_DOWN: {
if (reround>5) bump=1;
break;} /* r-h-d */
case DEC_ROUND_HALF_UP: {
if (reround>=5) bump=1;
break;} /* r-h-u */
case DEC_ROUND_UP: {
if (reround>0) bump=1;
break;} /* r-u */
case DEC_ROUND_CEILING: {
/* same as _UP for positive numbers, and as _DOWN for negatives */
if (!num->sign && reround>0) bump=1;
break;} /* r-c */
case DEC_ROUND_FLOOR: {
/* same as _UP for negative numbers, and as _DOWN for positive */
/* [negative reround cannot occur on 0] */
if (num->sign && reround>0) bump=1;
break;} /* r-f */
case DEC_ROUND_05UP: {
if (reround>0) { /* anything out there is 'sticky' */
/* bump iff lsd=0 or 5; this cannot carry so it could be */
/* effected immediately with no bump -- but the code */
/* is clearer if this is done the same way as the others */
if (*ulsd==0 || *ulsd==5) bump=1;
}
break;} /* r-r */
default: { /* e.g., DEC_ROUND_MAX */
set->status|=DEC_Invalid_context;
#if DECCHECK
printf("Unknown rounding mode: %ld\n", (LI)set->round);
#endif
break;}
} /* switch (not r-h-e) */
/* printf("ReRound: %ld bump: %ld\n", (LI)reround, (LI)bump); */
if (bump!=0) { /* need increment */
/* increment the coefficient; this might end up with 1000... */
/* (after the all nines case) */
ub=ulsd;
for(; ub-3>=umsd && UBTOUI(ub-3)==0x09090909; ub-=4) {
UBFROMUI(ub-3, 0); /* to 00000000 */
}
/* [note ub could now be to left of msd, and it is not safe */
/* to write to the left of the msd] */
/* now at most 3 digits left to non-9 (usually just the one) */
for (; ub>=umsd; *ub=0, ub--) {
if (*ub==9) continue; /* carry */
*ub+=1;
break;
}
if (ub<umsd) { /* had all-nines */
*umsd=1; /* coefficient to 1000... */
/* usually the 1000... coefficient can be used as-is */
if ((ulsd-umsd+1)==DECPMAX) {
num->exponent++;
}
else {
/* if coefficient is shorter than Pmax then num is */
/* subnormal, so extend it; this is safe as drop>0 */
/* (or, if the coefficient was supplied above, it could */
/* not be 9); this may make the result normal. */
ulsd++;
*ulsd=0;
/* [exponent unchanged] */
#if DECCHECK
if (num->exponent!=DECQTINY) /* sanity check */
printf("decFinalize: bad all-nines extend [^%ld, %ld]\n",
(LI)num->exponent, (LI)(ulsd-umsd+1));
#endif
} /* subnormal extend */
} /* had all-nines */
} /* bump needed */
} /* inexact rounding */
length=ulsd-umsd+1; /* recalculate (may be <DECPMAX) */
} /* need round (drop>0) */
/* The coefficient will now fit and has final length unless overflow */
/* decShowNum(num, "rounded"); */
/* if exponent is >=emax may have to clamp, overflow, or fold-down */
if (num->exponent>DECEMAX-(DECPMAX-1)) { /* is edge case */
/* printf("overflow checks...\n"); */
if (*ulsd==0 && ulsd==umsd) { /* have zero */
num->exponent=DECEMAX-(DECPMAX-1); /* clamp to max */
}
else if ((num->exponent+length-1)>DECEMAX) { /* > Nmax */
/* Overflow -- these could go straight to encoding, here, but */
/* instead num is adjusted to keep the code cleaner */
Flag needmax=0; /* 1 for finite result */
set->status|=(DEC_Overflow | DEC_Inexact);
switch (set->round) {
case DEC_ROUND_DOWN: {
needmax=1; /* never Infinity */
break;} /* r-d */
case DEC_ROUND_05UP: {
needmax=1; /* never Infinity */
break;} /* r-05 */
case DEC_ROUND_CEILING: {
if (num->sign) needmax=1; /* Infinity iff non-negative */
break;} /* r-c */
case DEC_ROUND_FLOOR: {
if (!num->sign) needmax=1; /* Infinity iff negative */
break;} /* r-f */
default: break; /* Infinity in all other cases */
}
if (!needmax) { /* easy .. set Infinity */
num->exponent=DECFLOAT_Inf;
*umsd=0; /* be clean: coefficient to 0 */
ulsd=umsd; /* .. */
}
else { /* return Nmax */
umsd=allnines; /* use constant array */
ulsd=allnines+DECPMAX-1;
num->exponent=DECEMAX-(DECPMAX-1);
}
}
else { /* no overflow but non-zero and may have to fold-down */
Int shift=num->exponent-(DECEMAX-(DECPMAX-1));
if (shift>0) { /* fold-down needed */
/* fold down needed; must copy to buffer in order to pad */
/* with zeros safely; fortunately this is not the worst case */
/* path because cannot have had a round */
uByte buffer[ROUNDUP(DECPMAX+3, 4)]; /* [+3 allows uInt padding] */
uByte *s=umsd; /* source */
uByte *t=buffer; /* safe target */
uByte *tlsd=buffer+(ulsd-umsd)+shift; /* target LSD */
/* printf("folddown shift=%ld\n", (LI)shift); */
for (; s<=ulsd; s+=4, t+=4) UBFROMUI(t, UBTOUI(s));
for (t=tlsd-shift+1; t<=tlsd; t+=4) UBFROMUI(t, 0); /* pad 0s */
num->exponent-=shift;
umsd=buffer;
ulsd=tlsd;
}
} /* fold-down? */
length=ulsd-umsd+1; /* recalculate length */
} /* high-end edge case */
} /* finite number */
/*------------------------------------------------------------------*/
/* At this point the result will properly fit the decFloat */
/* encoding, and it can be encoded with no possibility of error */
/*------------------------------------------------------------------*/
/* Following code does not alter coefficient (could be allnines array) */
/* fast path possible when DECPMAX digits */
if (length==DECPMAX) {
return decFloatFromBCD(df, num->exponent, umsd, num->sign);
} /* full-length */
/* slower path when not a full-length number; must care about length */
/* [coefficient length here will be < DECPMAX] */
if (!NUMISSPECIAL(num)) { /* is still finite */
/* encode the combination field and exponent continuation */
uInt uexp=(uInt)(num->exponent+DECBIAS); /* biased exponent */
uInt code=(uexp>>DECECONL)<<4; /* top two bits of exp */
/* [msd==0] */
/* look up the combination field and make high word */
encode=DECCOMBFROM[code]; /* indexed by (0-2)*16+msd */
encode|=(uexp<<(32-6-DECECONL)) & 0x03ffffff; /* exponent continuation */
}
else encode=num->exponent; /* special [already in word] */
encode|=num->sign; /* add sign */
/* private macro to extract a declet, n (where 0<=n<DECLETS and 0 */
/* refers to the declet from the least significant three digits) */
/* and put the corresponding DPD code into dpd. Access to umsd and */
/* ulsd (pointers to the most and least significant digit of the */
/* variable-length coefficient) is assumed, along with use of a */
/* working pointer, uInt *ub. */
/* As not full-length then chances are there are many leading zeros */
/* [and there may be a partial triad] */
#define getDPDt(dpd, n) ub=ulsd-(3*(n))-2; \
if (ub<umsd-2) dpd=0; \
else if (ub>=umsd) dpd=BCD2DPD[(*ub*256)+(*(ub+1)*16)+*(ub+2)]; \
else {dpd=*(ub+2); if (ub+1==umsd) dpd+=*(ub+1)*16; dpd=BCD2DPD[dpd];}
/* place the declets in the encoding words and copy to result (df), */
/* according to endianness; in all cases complete the sign word */
/* first */
#if DECPMAX==7
getDPDt(dpd, 1);
encode|=dpd<<10;
getDPDt(dpd, 0);
encode|=dpd;
DFWORD(df, 0)=encode; /* just the one word */
#elif DECPMAX==16
getDPDt(dpd, 4); encode|=dpd<<8;
getDPDt(dpd, 3); encode|=dpd>>2;
DFWORD(df, 0)=encode;
encode=dpd<<30;
getDPDt(dpd, 2); encode|=dpd<<20;
getDPDt(dpd, 1); encode|=dpd<<10;
getDPDt(dpd, 0); encode|=dpd;
DFWORD(df, 1)=encode;
#elif DECPMAX==34
getDPDt(dpd,10); encode|=dpd<<4;
getDPDt(dpd, 9); encode|=dpd>>6;
DFWORD(df, 0)=encode;
encode=dpd<<26;
getDPDt(dpd, 8); encode|=dpd<<16;
getDPDt(dpd, 7); encode|=dpd<<6;
getDPDt(dpd, 6); encode|=dpd>>4;
DFWORD(df, 1)=encode;
encode=dpd<<28;
getDPDt(dpd, 5); encode|=dpd<<18;
getDPDt(dpd, 4); encode|=dpd<<8;
getDPDt(dpd, 3); encode|=dpd>>2;
DFWORD(df, 2)=encode;
encode=dpd<<30;
getDPDt(dpd, 2); encode|=dpd<<20;
getDPDt(dpd, 1); encode|=dpd<<10;
getDPDt(dpd, 0); encode|=dpd;
DFWORD(df, 3)=encode;
#endif
/* printf("Status: %08lx\n", (LI)set->status); */
/* decFloatShow(df, "final2"); */
return df;
} /* decFinalize */
/* ------------------------------------------------------------------ */
/* decFloatFromBCD -- set decFloat from exponent, BCD8, and sign */
/* */
/* df is the target decFloat */
/* exp is the in-range unbiased exponent, q, or a special value in */
/* the form returned by decFloatGetExponent */
/* bcdar holds DECPMAX digits to set the coefficient from, one */
/* digit in each byte (BCD8 encoding); the first (MSD) is ignored */
/* if df is a NaN; all are ignored if df is infinite. */
/* All bytes must be in 0-9; results are undefined otherwise. */
/* sig is DECFLOAT_Sign to set the sign bit, 0 otherwise */
/* returns df, which will be canonical */
/* */
/* No error is possible, and no status will be set. */
/* ------------------------------------------------------------------ */
decFloat * decFloatFromBCD(decFloat *df, Int exp, const uByte *bcdar,
Int sig) {
uInt encode, dpd; /* work */
const uByte *ub; /* .. */
if (EXPISSPECIAL(exp)) encode=exp|sig;/* specials already encoded */
else { /* is finite */
/* encode the combination field and exponent continuation */
uInt uexp=(uInt)(exp+DECBIAS); /* biased exponent */
uInt code=(uexp>>DECECONL)<<4; /* top two bits of exp */
code+=bcdar[0]; /* add msd */
/* look up the combination field and make high word */
encode=DECCOMBFROM[code]|sig; /* indexed by (0-2)*16+msd */
encode|=(uexp<<(32-6-DECECONL)) & 0x03ffffff; /* exponent continuation */
}
/* private macro to extract a declet, n (where 0<=n<DECLETS and 0 */
/* refers to the declet from the least significant three digits) */
/* and put the corresponding DPD code into dpd. */
/* Use of a working pointer, uInt *ub, is assumed. */
#define getDPDb(dpd, n) ub=bcdar+DECPMAX-1-(3*(n))-2; \
dpd=BCD2DPD[(*ub*256)+(*(ub+1)*16)+*(ub+2)];
/* place the declets in the encoding words and copy to result (df), */
/* according to endianness; in all cases complete the sign word */
/* first */
#if DECPMAX==7
getDPDb(dpd, 1);
encode|=dpd<<10;
getDPDb(dpd, 0);
encode|=dpd;
DFWORD(df, 0)=encode; /* just the one word */
#elif DECPMAX==16
getDPDb(dpd, 4); encode|=dpd<<8;
getDPDb(dpd, 3); encode|=dpd>>2;
DFWORD(df, 0)=encode;
encode=dpd<<30;
getDPDb(dpd, 2); encode|=dpd<<20;
getDPDb(dpd, 1); encode|=dpd<<10;
getDPDb(dpd, 0); encode|=dpd;
DFWORD(df, 1)=encode;
#elif DECPMAX==34
getDPDb(dpd,10); encode|=dpd<<4;
getDPDb(dpd, 9); encode|=dpd>>6;
DFWORD(df, 0)=encode;
encode=dpd<<26;
getDPDb(dpd, 8); encode|=dpd<<16;
getDPDb(dpd, 7); encode|=dpd<<6;
getDPDb(dpd, 6); encode|=dpd>>4;
DFWORD(df, 1)=encode;
encode=dpd<<28;
getDPDb(dpd, 5); encode|=dpd<<18;
getDPDb(dpd, 4); encode|=dpd<<8;
getDPDb(dpd, 3); encode|=dpd>>2;
DFWORD(df, 2)=encode;
encode=dpd<<30;
getDPDb(dpd, 2); encode|=dpd<<20;
getDPDb(dpd, 1); encode|=dpd<<10;
getDPDb(dpd, 0); encode|=dpd;
DFWORD(df, 3)=encode;
#endif
/* decFloatShow(df, "fromB"); */
return df;
} /* decFloatFromBCD */
/* ------------------------------------------------------------------ */
/* decFloatFromPacked -- set decFloat from exponent and packed BCD */
/* */
/* df is the target decFloat */
/* exp is the in-range unbiased exponent, q, or a special value in */
/* the form returned by decFloatGetExponent */
/* packed holds DECPMAX packed decimal digits plus a sign nibble */
/* (all 6 codes are OK); the first (MSD) is ignored if df is a NaN */
/* and all except sign are ignored if df is infinite. For DOUBLE */
/* and QUAD the first (pad) nibble is also ignored in all cases. */
/* All coefficient nibbles must be in 0-9 and sign in A-F; results */
/* are undefined otherwise. */
/* returns df, which will be canonical */
/* */
/* No error is possible, and no status will be set. */
/* ------------------------------------------------------------------ */
decFloat * decFloatFromPacked(decFloat *df, Int exp, const uByte *packed) {
uByte bcdar[DECPMAX+2]; /* work [+1 for pad, +1 for sign] */
const uByte *ip; /* .. */
uByte *op; /* .. */
Int sig=0; /* sign */
/* expand coefficient and sign to BCDAR */
#if SINGLE
op=bcdar+1; /* no pad digit */
#else
op=bcdar; /* first (pad) digit ignored */
#endif
for (ip=packed; ip<packed+((DECPMAX+2)/2); ip++) {
*op++=*ip>>4;
*op++=(uByte)(*ip&0x0f); /* [final nibble is sign] */
}
op--; /* -> sign byte */
if (*op==DECPMINUS || *op==DECPMINUSALT) sig=DECFLOAT_Sign;
if (EXPISSPECIAL(exp)) { /* Infinity or NaN */
if (!EXPISINF(exp)) bcdar[1]=0; /* a NaN: ignore MSD */
else memset(bcdar+1, 0, DECPMAX); /* Infinite: coefficient to 0 */
}
return decFloatFromBCD(df, exp, bcdar+1, sig);
} /* decFloatFromPacked */
/* ------------------------------------------------------------------ */
/* decFloatFromPackedChecked -- set from exponent and packed; checked */
/* */
/* df is the target decFloat */
/* exp is the in-range unbiased exponent, q, or a special value in */
/* the form returned by decFloatGetExponent */
/* packed holds DECPMAX packed decimal digits plus a sign nibble */
/* (all 6 codes are OK); the first (MSD) must be 0 if df is a NaN */
/* and all digits must be 0 if df is infinite. For DOUBLE and */
/* QUAD the first (pad) nibble must be 0. */
/* All coefficient nibbles must be in 0-9 and sign in A-F. */
/* returns df, which will be canonical or NULL if any of the */
/* requirements are not met (if this case df is unchanged); that */
/* is, the input data must be as returned by decFloatToPacked, */
/* except that all six sign codes are accepted. */
/* */
/* No status will be set. */
/* ------------------------------------------------------------------ */
decFloat * decFloatFromPackedChecked(decFloat *df, Int exp,
const uByte *packed) {
uByte bcdar[DECPMAX+2]; /* work [+1 for pad, +1 for sign] */
const uByte *ip; /* .. */
uByte *op; /* .. */
Int sig=0; /* sign */
/* expand coefficient and sign to BCDAR */
#if SINGLE
op=bcdar+1; /* no pad digit */
#else
op=bcdar; /* first (pad) digit here */
#endif
for (ip=packed; ip<packed+((DECPMAX+2)/2); ip++) {
*op=*ip>>4;
if (*op>9) return NULL;
op++;
*op=(uByte)(*ip&0x0f); /* [final nibble is sign] */
if (*op>9 && ip<packed+((DECPMAX+2)/2)-1) return NULL;
op++;
}
op--; /* -> sign byte */
if (*op<=9) return NULL; /* bad sign */
if (*op==DECPMINUS || *op==DECPMINUSALT) sig=DECFLOAT_Sign;
#if !SINGLE
if (bcdar[0]!=0) return NULL; /* bad pad nibble */
#endif
if (EXPISNAN(exp)) { /* a NaN */
if (bcdar[1]!=0) return NULL; /* bad msd */
} /* NaN */
else if (EXPISINF(exp)) { /* is infinite */
Int i;
for (i=0; i<DECPMAX; i++) {
if (bcdar[i+1]!=0) return NULL; /* should be all zeros */
}
} /* infinity */
else { /* finite */
/* check the exponent is in range */
if (exp>DECEMAX-DECPMAX+1) return NULL;
if (exp<DECEMIN-DECPMAX+1) return NULL;
}
return decFloatFromBCD(df, exp, bcdar+1, sig);
} /* decFloatFromPacked */
/* ------------------------------------------------------------------ */
/* decFloatFromString -- conversion from numeric string */
/* */
/* result is the decFloat 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), \0-terminated */
/* If there are too many significant digits in the */
/* coefficient it will be rounded. */
/* set is the context */
/* returns result */
/* */
/* The length of the coefficient and the size of the exponent are */
/* checked by this routine, so the correct error (Underflow or */
/* Overflow) can be reported or rounding applied, as necessary. */
/* */
/* There is no limit to the coefficient length for finite inputs; */
/* NaN payloads must be integers with no more than DECPMAX-1 digits. */
/* Exponents may have up to nine significant digits. */
/* */
/* If bad syntax is detected, the result will be a quiet NaN. */
/* ------------------------------------------------------------------ */
decFloat * decFloatFromString(decFloat *result, const char *string,
decContext *set) {
Int digits; /* count of digits in coefficient */
const char *dotchar=NULL; /* where dot was found [NULL if none] */
const char *cfirst=string; /* -> first character of decimal part */
const char *c; /* work */
uByte *ub; /* .. */
uInt uiwork; /* for macros */
bcdnum num; /* collects data for finishing */
uInt error=DEC_Conversion_syntax; /* assume the worst */
uByte buffer[ROUNDUP(DECSTRING+11, 8)]; /* room for most coefficents, */
/* some common rounding, +3, & pad */
#if DECTRACE
/* printf("FromString %s ...\n", string); */
#endif
for(;;) { /* once-only 'loop' */
num.sign=0; /* assume non-negative */
num.msd=buffer; /* MSD is here always */
/* detect and validate the coefficient, including any leading, */
/* trailing, or embedded '.' */
/* [could test four-at-a-time here (saving 10% for decQuads), */
/* but that risks storage violation because the position of the */
/* terminator is unknown] */
for (c=string;; c++) { /* -> input character */
if (((unsigned)(*c-'0'))<=9) continue; /* '0' through '9' is good */
if (*c=='\0') break; /* most common non-digit */
if (*c=='.') {
if (dotchar!=NULL) break; /* not first '.' */
dotchar=c; /* record offset into decimal part */
continue;}
if (c==string) { /* first in string... */
if (*c=='-') { /* valid - sign */
cfirst++;
num.sign=DECFLOAT_Sign;
continue;}
if (*c=='+') { /* valid + sign */
cfirst++;
continue;}
}
/* *c is not a digit, terminator, or a valid +, -, or '.' */
break;
} /* c loop */
digits=(uInt)(c-cfirst); /* digits (+1 if a dot) */
if (digits>0) { /* had digits and/or dot */
const char *clast=c-1; /* note last coefficient char position */
Int exp=0; /* exponent accumulator */
if (*c!='\0') { /* something follows the coefficient */
uInt edig; /* unsigned work */
/* had some digits and more to come; expect E[+|-]nnn now */
const char *firstexp; /* exponent first non-zero */
if (*c!='E' && *c!='e') break;
c++; /* to (optional) sign */
if (*c=='-' || *c=='+') c++; /* step over sign (c=clast+2) */
if (*c=='\0') break; /* no digits! (e.g., '1.2E') */
for (; *c=='0';) c++; /* skip leading zeros [even last] */
firstexp=c; /* remember start [maybe '\0'] */
/* gather exponent digits */
edig=(uInt)*c-(uInt)'0';
if (edig<=9) { /* [check not bad or terminator] */
exp+=edig; /* avoid initial X10 */
c++;
for (;; c++) {
edig=(uInt)*c-(uInt)'0';
if (edig>9) break;
exp=exp*10+edig;
}
}
/* if not now on the '\0', *c must not be a digit */
if (*c!='\0') break;
/* (this next test must be after the syntax checks) */
/* if definitely more than the possible digits for format then */
/* the exponent may have wrapped, so simply set it to a certain */
/* over/underflow value */
if (c>firstexp+DECEMAXD) exp=DECEMAX*2;
if (*(clast+2)=='-') exp=-exp; /* was negative */
} /* digits>0 */
if (dotchar!=NULL) { /* had a '.' */
digits--; /* remove from digits count */
if (digits==0) break; /* was dot alone: bad syntax */
exp-=(Int)(clast-dotchar); /* adjust exponent */
/* [the '.' can now be ignored] */
}
num.exponent=exp; /* exponent is good; store it */
/* Here when whole string has been inspected and syntax is good */
/* cfirst->first digit or dot, clast->last digit or dot */
error=0; /* no error possible now */
/* if the number of digits in the coefficient will fit in buffer */
/* then it can simply be converted to bcd8 and copied -- decFinalize */
/* will take care of leading zeros and rounding; the buffer is big */
/* enough for all canonical coefficients, including 0.00000nn... */
ub=buffer;
if (digits<=(Int)(sizeof(buffer)-3)) { /* [-3 allows by-4s copy] */
c=cfirst;
if (dotchar!=NULL) { /* a dot to worry about */
if (*(c+1)=='.') { /* common canonical case */
*ub++=(uByte)(*c-'0'); /* copy leading digit */
c+=2; /* prepare to handle rest */
}
else for (; c<=clast;) { /* '.' could be anywhere */
/* as usual, go by fours when safe; NB it has been asserted */
/* that a '.' does not have the same mask as a digit */
if (c<=clast-3 /* safe for four */
&& (UBTOUI(c)&0xf0f0f0f0)==CHARMASK) { /* test four */
UBFROMUI(ub, UBTOUI(c)&0x0f0f0f0f); /* to BCD8 */
ub+=4;
c+=4;
continue;
}
if (*c=='.') { /* found the dot */
c++; /* step over it .. */
break; /* .. and handle the rest */
}
*ub++=(uByte)(*c++-'0');
}
} /* had dot */
/* Now no dot; do this by fours (where safe) */
for (; c<=clast-3; c+=4, ub+=4) UBFROMUI(ub, UBTOUI(c)&0x0f0f0f0f);
for (; c<=clast; c++, ub++) *ub=(uByte)(*c-'0');
num.lsd=buffer+digits-1; /* record new LSD */
} /* fits */
else { /* too long for buffer */
/* [This is a rare and unusual case; arbitrary-length input] */
/* strip leading zeros [but leave final 0 if all 0's] */
if (*cfirst=='.') cfirst++; /* step past dot at start */
if (*cfirst=='0') { /* [cfirst always -> digit] */
for (; cfirst<clast; cfirst++) {
if (*cfirst!='0') { /* non-zero found */
if (*cfirst=='.') continue; /* [ignore] */
break; /* done */
}
digits--; /* 0 stripped */
} /* cfirst */
} /* at least one leading 0 */
/* the coefficient is now as short as possible, but may still */
/* be too long; copy up to Pmax+1 digits to the buffer, then */
/* just record any non-zeros (set round-for-reround digit) */
for (c=cfirst; c<=clast && ub<=buffer+DECPMAX; c++) {
/* (see commentary just above) */
if (c<=clast-3 /* safe for four */
&& (UBTOUI(c)&0xf0f0f0f0)==CHARMASK) { /* four digits */
UBFROMUI(ub, UBTOUI(c)&0x0f0f0f0f); /* to BCD8 */
ub+=4;
c+=3; /* [will become 4] */
continue;
}
if (*c=='.') continue; /* [ignore] */
*ub++=(uByte)(*c-'0');
}
ub--; /* -> LSD */
for (; c<=clast; c++) { /* inspect remaining chars */
if (*c!='0') { /* sticky bit needed */
if (*c=='.') continue; /* [ignore] */
*ub=DECSTICKYTAB[*ub]; /* update round-for-reround */
break; /* no need to look at more */
}
}
num.lsd=ub; /* record LSD */
/* adjust exponent for dropped digits */
num.exponent+=digits-(Int)(ub-buffer+1);
} /* too long for buffer */
} /* digits or dot */
else { /* no digits or dot were found */
if (*c=='\0') break; /* nothing to come is bad */
/* only Infinities and NaNs are allowed, here */
buffer[0]=0; /* default a coefficient of 0 */
num.lsd=buffer; /* .. */
if (decBiStr(c, "infinity", "INFINITY")
|| decBiStr(c, "inf", "INF")) num.exponent=DECFLOAT_Inf;
else { /* should be a NaN */
num.exponent=DECFLOAT_qNaN; /* assume quiet NaN */
if (*c=='s' || *c=='S') { /* probably an sNaN */
c++;
num.exponent=DECFLOAT_sNaN; /* assume is in fact sNaN */
}
if (*c!='N' && *c!='n') break; /* check caseless "NaN" */
c++;
if (*c!='a' && *c!='A') break; /* .. */
c++;
if (*c!='N' && *c!='n') break; /* .. */
c++;
/* now either nothing, or nnnn payload (no dots), expected */
/* -> start of integer, and skip leading 0s [including plain 0] */
for (cfirst=c; *cfirst=='0';) cfirst++;
if (*cfirst!='\0') { /* not empty or all-0, payload */
/* payload found; check all valid digits and copy to buffer as bcd8 */
ub=buffer;
for (c=cfirst;; c++, ub++) {
if ((unsigned)(*c-'0')>9) break; /* quit if not 0-9 */
if (c-cfirst==DECPMAX-1) break; /* too many digits */
*ub=(uByte)(*c-'0'); /* good bcd8 */
}
if (*c!='\0') break; /* not all digits, or too many */
num.lsd=ub-1; /* record new LSD */
}
} /* NaN or sNaN */
error=0; /* syntax is OK */
break; /* done with specials */
} /* digits=0 (special expected) */
break;
} /* [for(;;) break] */
/* decShowNum(&num, "fromStr"); */