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gcc/libdecnumber/dpd/decimal64.c
Richard Sandiford 8e322cb4b9 Update copyright in libdecnumber. 
From-SVN: r195821
2013-02-06 22:09:24 +00:00

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/* Decimal 64-bit format module for the decNumber C Library.
Copyright (C) 2005-2013 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 64-bit format module */
/* ------------------------------------------------------------------ */
/* This module comprises the routines for decimal64 format numbers. */
/* Conversions are supplied to and from decNumber and String. */
/* */
/* This is used when decNumber provides operations, either for all */
/* operations or as a proxy between decNumber and decSingle. */
/* */
/* Error handling is the same as decNumber (qv.). */
/* ------------------------------------------------------------------ */
#include <string.h> /* [for memset/memcpy] */
#include <stdio.h> /* [for printf] */
#include "dconfig.h" /* GCC definitions */
#define DECNUMDIGITS 16 /* make decNumbers with space for 16 */
#include "decNumber.h" /* base number library */
#include "decNumberLocal.h" /* decNumber local types, etc. */
#include "decimal64.h" /* our primary include */
/* Utility routines and tables [in decimal64.c]; externs for C++ */
extern const uInt COMBEXP[32], COMBMSD[32];
extern const uShort DPD2BIN[1024];
extern const uShort BIN2DPD[1000];
extern const uByte BIN2CHAR[4001];
extern void decDigitsFromDPD(decNumber *, const uInt *, Int);
extern void decDigitsToDPD(const decNumber *, uInt *, Int);
#if DECTRACE || DECCHECK
void decimal64Show(const decimal64 *); /* for debug */
extern void decNumberShow(const decNumber *); /* .. */
#endif
/* Useful macro */
/* Clear a structure (e.g., a decNumber) */
#define DEC_clear(d) memset(d, 0, sizeof(*d))
/* define and include the tables to use for conversions */
#define DEC_BIN2CHAR 1
#define DEC_DPD2BIN 1
#define DEC_BIN2DPD 1 /* used for all sizes */
#include "decDPD.h" /* lookup tables */
/* ------------------------------------------------------------------ */
/* decimal64FromNumber -- convert decNumber to decimal64 */
/* */
/* ds is the target decimal64 */
/* 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 DECIMAL64_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. */
/* ------------------------------------------------------------------ */
decimal64 * decimal64FromNumber(decimal64 *d64, const decNumber *dn,
decContext *set) {
uInt status=0; /* status accumulator */
Int ae; /* adjusted exponent */
decNumber dw; /* work */
decContext dc; /* .. */
uInt comb, exp; /* .. */
uInt uiwork; /* for macros */
uInt targar[2]={0, 0}; /* target 64-bit */
#define targhi targar[1] /* name the word with the sign */
#define targlo targar[0] /* and the other */
/* If the number has too many digits, or the exponent could be */
/* out of range then reduce the number under the appropriate */
/* constraints. This could push the number to Infinity or zero, */
/* so this check and rounding must be done before generating the */
/* decimal64] */
ae=dn->exponent+dn->digits-1; /* [0 if special] */
if (dn->digits>DECIMAL64_Pmax /* too many digits */
|| ae>DECIMAL64_Emax /* likely overflow */
|| ae<DECIMAL64_Emin) { /* likely underflow */
decContextDefault(&dc, DEC_INIT_DECIMAL64); /* [no traps] */
dc.round=set->round; /* use supplied rounding */
decNumberPlus(&dw, dn, &dc); /* (round and check) */
/* [this changes -0 to 0, so enforce the sign...] */
dw.bits|=dn->bits&DECNEG;
status=dc.status; /* save status */
dn=&dw; /* use the work number */
} /* maybe out of range */
if (dn->bits&DECSPECIAL) { /* a special value */
if (dn->bits&DECINF) targhi=DECIMAL_Inf<<24;
else { /* sNaN or qNaN */
if ((*dn->lsu!=0 || dn->digits>1) /* non-zero coefficient */
&& (dn->digits<DECIMAL64_Pmax)) { /* coefficient fits */
decDigitsToDPD(dn, targar, 0);
}
if (dn->bits&DECNAN) targhi|=DECIMAL_NaN<<24;
else targhi|=DECIMAL_sNaN<<24;
} /* a NaN */
} /* special */
else { /* is finite */
if (decNumberIsZero(dn)) { /* is a zero */
/* set and clamp exponent */
if (dn->exponent<-DECIMAL64_Bias) {
exp=0; /* low clamp */
status|=DEC_Clamped;
}
else {
exp=dn->exponent+DECIMAL64_Bias; /* bias exponent */
if (exp>DECIMAL64_Ehigh) { /* top clamp */
exp=DECIMAL64_Ehigh;
status|=DEC_Clamped;
}
}
comb=(exp>>5) & 0x18; /* msd=0, exp top 2 bits .. */
}
else { /* non-zero finite number */
uInt msd; /* work */
Int pad=0; /* coefficient pad digits */
/* the dn is known to fit, but it may need to be padded */
exp=(uInt)(dn->exponent+DECIMAL64_Bias); /* bias exponent */
if (exp>DECIMAL64_Ehigh) { /* fold-down case */
pad=exp-DECIMAL64_Ehigh;
exp=DECIMAL64_Ehigh; /* [to maximum] */
status|=DEC_Clamped;
}
/* fastpath common case */
if (DECDPUN==3 && pad==0) {
uInt dpd[6]={0,0,0,0,0,0};
uInt i;
Int d=dn->digits;
for (i=0; d>0; i++, d-=3) dpd[i]=BIN2DPD[dn->lsu[i]];
targlo =dpd[0];
targlo|=dpd[1]<<10;
targlo|=dpd[2]<<20;
if (dn->digits>6) {
targlo|=dpd[3]<<30;
targhi =dpd[3]>>2;
targhi|=dpd[4]<<8;
}
msd=dpd[5]; /* [did not really need conversion] */
}
else { /* general case */
decDigitsToDPD(dn, targar, pad);
/* save and clear the top digit */
msd=targhi>>18;
targhi&=0x0003ffff;
}
/* create the combination field */
if (msd>=8) comb=0x18 | ((exp>>7) & 0x06) | (msd & 0x01);
else comb=((exp>>5) & 0x18) | msd;
}
targhi|=comb<<26; /* add combination field .. */
targhi|=(exp&0xff)<<18; /* .. and exponent continuation */
} /* finite */
if (dn->bits&DECNEG) targhi|=0x80000000; /* add sign bit */
/* now write to storage; this is now always endian */
if (DECLITEND) {
/* lo int then hi */
UBFROMUI(d64->bytes, targar[0]);
UBFROMUI(d64->bytes+4, targar[1]);
}
else {
/* hi int then lo */
UBFROMUI(d64->bytes, targar[1]);
UBFROMUI(d64->bytes+4, targar[0]);
}
if (status!=0) decContextSetStatus(set, status); /* pass on status */
/* decimal64Show(d64); */
return d64;
} /* decimal64FromNumber */
/* ------------------------------------------------------------------ */
/* decimal64ToNumber -- convert decimal64 to decNumber */
/* d64 is the source decimal64 */
/* dn is the target number, with appropriate space */
/* No error is possible. */
/* ------------------------------------------------------------------ */
decNumber * decimal64ToNumber(const decimal64 *d64, decNumber *dn) {
uInt msd; /* coefficient MSD */
uInt exp; /* exponent top two bits */
uInt comb; /* combination field */
Int need; /* work */
uInt uiwork; /* for macros */
uInt sourar[2]; /* source 64-bit */
#define sourhi sourar[1] /* name the word with the sign */
#define sourlo sourar[0] /* and the lower word */
/* load source from storage; this is endian */
if (DECLITEND) {
sourlo=UBTOUI(d64->bytes ); /* directly load the low int */
sourhi=UBTOUI(d64->bytes+4); /* then the high int */
}
else {
sourhi=UBTOUI(d64->bytes ); /* directly load the high int */
sourlo=UBTOUI(d64->bytes+4); /* then the low int */
}
comb=(sourhi>>26)&0x1f; /* combination field */
decNumberZero(dn); /* clean number */
if (sourhi&0x80000000) dn->bits=DECNEG; /* set sign if negative */
msd=COMBMSD[comb]; /* decode the combination field */
exp=COMBEXP[comb]; /* .. */
if (exp==3) { /* is a special */
if (msd==0) {
dn->bits|=DECINF;
return dn; /* no coefficient needed */
}
else if (sourhi&0x02000000) dn->bits|=DECSNAN;
else dn->bits|=DECNAN;
msd=0; /* no top digit */
}
else { /* is a finite number */
dn->exponent=(exp<<8)+((sourhi>>18)&0xff)-DECIMAL64_Bias; /* unbiased */
}
/* get the coefficient */
sourhi&=0x0003ffff; /* clean coefficient continuation */
if (msd) { /* non-zero msd */
sourhi|=msd<<18; /* prefix to coefficient */
need=6; /* process 6 declets */
}
else { /* msd=0 */
if (!sourhi) { /* top word 0 */
if (!sourlo) return dn; /* easy: coefficient is 0 */
need=3; /* process at least 3 declets */
if (sourlo&0xc0000000) need++; /* process 4 declets */
/* [could reduce some more, here] */
}
else { /* some bits in top word, msd=0 */
need=4; /* process at least 4 declets */
if (sourhi&0x0003ff00) need++; /* top declet!=0, process 5 */
}
} /*msd=0 */
decDigitsFromDPD(dn, sourar, need); /* process declets */
return dn;
} /* decimal64ToNumber */
/* ------------------------------------------------------------------ */
/* to-scientific-string -- conversion to numeric string */
/* to-engineering-string -- conversion to numeric string */
/* */
/* decimal64ToString(d64, string); */
/* decimal64ToEngString(d64, string); */
/* */
/* d64 is the decimal64 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 * decimal64ToEngString(const decimal64 *d64, char *string){
decNumber dn; /* work */
decimal64ToNumber(d64, &dn);
decNumberToEngString(&dn, string);
return string;
} /* decimal64ToEngString */
char * decimal64ToString(const decimal64 *d64, char *string){
uInt msd; /* coefficient MSD */
Int exp; /* exponent top two bits or full */
uInt comb; /* combination field */
char *cstart; /* coefficient start */
char *c; /* output pointer in string */
const uByte *u; /* work */
char *s, *t; /* .. (source, target) */
Int dpd; /* .. */
Int pre, e; /* .. */
uInt uiwork; /* for macros */
uInt sourar[2]; /* source 64-bit */
#define sourhi sourar[1] /* name the word with the sign */
#define sourlo sourar[0] /* and the lower word */
/* load source from storage; this is endian */
if (DECLITEND) {
sourlo=UBTOUI(d64->bytes ); /* directly load the low int */
sourhi=UBTOUI(d64->bytes+4); /* then the high int */
}
else {
sourhi=UBTOUI(d64->bytes ); /* directly load the high int */
sourlo=UBTOUI(d64->bytes+4); /* then the low int */
}
c=string; /* where result will go */
if (((Int)sourhi)<0) *c++='-'; /* handle sign */
comb=(sourhi>>26)&0x1f; /* combination field */
msd=COMBMSD[comb]; /* decode the combination field */
exp=COMBEXP[comb]; /* .. */
if (exp==3) {
if (msd==0) { /* infinity */
strcpy(c, "Inf");
strcpy(c+3, "inity");
return string; /* easy */
}
if (sourhi&0x02000000) *c++='s'; /* sNaN */
strcpy(c, "NaN"); /* complete word */
c+=3; /* step past */
if (sourlo==0 && (sourhi&0x0003ffff)==0) return string; /* zero payload */
/* otherwise drop through to add integer; set correct exp */
exp=0; msd=0; /* setup for following code */
}
else exp=(exp<<8)+((sourhi>>18)&0xff)-DECIMAL64_Bias;
/* convert 16 digits of significand to characters */
cstart=c; /* save start of coefficient */
if (msd) *c++='0'+(char)msd; /* non-zero most significant digit */
/* Now decode the declets. After extracting each one, it is */
/* decoded to binary and then to a 4-char sequence by table lookup; */
/* the 4-chars are a 1-char length (significant digits, except 000 */
/* has length 0). This allows us to left-align the first declet */
/* with non-zero content, then remaining ones are full 3-char */
/* length. We use fixed-length memcpys because variable-length */
/* causes a subroutine call in GCC. (These are length 4 for speed */
/* and are safe because the array has an extra terminator byte.) */
#define dpd2char u=&BIN2CHAR[DPD2BIN[dpd]*4]; \
if (c!=cstart) {memcpy(c, u+1, 4); c+=3;} \
else if (*u) {memcpy(c, u+4-*u, 4); c+=*u;}
dpd=(sourhi>>8)&0x3ff; /* declet 1 */
dpd2char;
dpd=((sourhi&0xff)<<2) | (sourlo>>30); /* declet 2 */
dpd2char;
dpd=(sourlo>>20)&0x3ff; /* declet 3 */
dpd2char;
dpd=(sourlo>>10)&0x3ff; /* declet 4 */
dpd2char;
dpd=(sourlo)&0x3ff; /* declet 5 */
dpd2char;
if (c==cstart) *c++='0'; /* all zeros -- make 0 */
if (exp==0) { /* integer or NaN case -- easy */
*c='\0'; /* terminate */
return string;
}
/* non-0 exponent */
e=0; /* assume no E */
pre=c-cstart+exp;
/* [here, pre-exp is the digits count (==1 for zero)] */
if (exp>0 || pre<-5) { /* need exponential form */
e=pre-1; /* calculate E value */
pre=1; /* assume one digit before '.' */
} /* exponential form */
/* modify the coefficient, adding 0s, '.', and E+nn as needed */
s=c-1; /* source (LSD) */
if (pre>0) { /* ddd.ddd (plain), perhaps with E */
char *dotat=cstart+pre;
if (dotat<c) { /* if embedded dot needed... */
t=c; /* target */
for (; s>=dotat; s--, t--) *t=*s; /* open the gap; leave t at gap */
*t='.'; /* insert the dot */
c++; /* length increased by one */
}
/* finally add the E-part, if needed; it will never be 0, and has */
/* a maximum length of 3 digits */
if (e!=0) {
*c++='E'; /* starts with E */
*c++='+'; /* assume positive */
if (e<0) {
*(c-1)='-'; /* oops, need '-' */
e=-e; /* uInt, please */
}
u=&BIN2CHAR[e*4]; /* -> length byte */
memcpy(c, u+4-*u, 4); /* copy fixed 4 characters [is safe] */
c+=*u; /* bump pointer appropriately */
}
*c='\0'; /* add terminator */
/*printf("res %s\n", string); */
return string;
} /* pre>0 */
/* -5<=pre<=0: here for plain 0.ddd or 0.000ddd forms (can never have E) */
t=c+1-pre;
*(t+1)='\0'; /* can add terminator now */
for (; s>=cstart; s--, t--) *t=*s; /* shift whole coefficient right */
c=cstart;
*c++='0'; /* always starts with 0. */
*c++='.';
for (; pre<0; pre++) *c++='0'; /* add any 0's after '.' */
/*printf("res %s\n", string); */
return string;
} /* decimal64ToString */
/* ------------------------------------------------------------------ */
/* to-number -- conversion from numeric string */
/* */
/* decimal64FromString(result, string, set); */
/* */
/* result is the decimal64 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 decimal64 NaN. */
/* ------------------------------------------------------------------ */
decimal64 * decimal64FromString(decimal64 *result, const char *string,
decContext *set) {
decContext dc; /* work */
decNumber dn; /* .. */
decContextDefault(&dc, DEC_INIT_DECIMAL64); /* no traps, please */
dc.round=set->round; /* use supplied rounding */
decNumberFromString(&dn, string, &dc); /* will round if needed */
decimal64FromNumber(result, &dn, &dc);
if (dc.status!=0) { /* something happened */
decContextSetStatus(set, dc.status); /* .. pass it on */
}
return result;
} /* decimal64FromString */
/* ------------------------------------------------------------------ */
/* decimal64IsCanonical -- test whether encoding is canonical */
/* d64 is the source decimal64 */
/* returns 1 if the encoding of d64 is canonical, 0 otherwise */
/* No error is possible. */
/* ------------------------------------------------------------------ */
uInt decimal64IsCanonical(const decimal64 *d64) {
decNumber dn; /* work */
decimal64 canon; /* .. */
decContext dc; /* .. */
decContextDefault(&dc, DEC_INIT_DECIMAL64);
decimal64ToNumber(d64, &dn);
decimal64FromNumber(&canon, &dn, &dc);/* canon will now be canonical */
return memcmp(d64, &canon, DECIMAL64_Bytes)==0;
} /* decimal64IsCanonical */
/* ------------------------------------------------------------------ */
/* decimal64Canonical -- copy an encoding, ensuring it is canonical */
/* d64 is the source decimal64 */
/* result is the target (may be the same decimal64) */
/* returns result */
/* No error is possible. */
/* ------------------------------------------------------------------ */
decimal64 * decimal64Canonical(decimal64 *result, const decimal64 *d64) {
decNumber dn; /* work */
decContext dc; /* .. */
decContextDefault(&dc, DEC_INIT_DECIMAL64);
decimal64ToNumber(d64, &dn);
decimal64FromNumber(result, &dn, &dc);/* result will now be canonical */
return result;
} /* decimal64Canonical */
#if DECTRACE || DECCHECK
/* Macros for accessing decimal64 fields. These assume the
argument is a reference (pointer) to the decimal64 structure,
and the decimal64 is in network byte order (big-endian) */
/* Get sign */
#define decimal64Sign(d) ((unsigned)(d)->bytes[0]>>7)
/* Get combination field */
#define decimal64Comb(d) (((d)->bytes[0] & 0x7c)>>2)
/* Get exponent continuation [does not remove bias] */
#define decimal64ExpCon(d) ((((d)->bytes[0] & 0x03)<<6) \
| ((unsigned)(d)->bytes[1]>>2))
/* Set sign [this assumes sign previously 0] */
#define decimal64SetSign(d, b) { \
(d)->bytes[0]|=((unsigned)(b)<<7);}
/* Set exponent continuation [does not apply bias] */
/* This assumes range has been checked and exponent previously 0; */
/* type of exponent must be unsigned */
#define decimal64SetExpCon(d, e) { \
(d)->bytes[0]|=(uByte)((e)>>6); \
(d)->bytes[1]|=(uByte)(((e)&0x3F)<<2);}
/* ------------------------------------------------------------------ */
/* decimal64Show -- display a decimal64 in hexadecimal [debug aid] */
/* d64 -- the number to show */
/* ------------------------------------------------------------------ */
/* Also shows sign/cob/expconfields extracted */
void decimal64Show(const decimal64 *d64) {
char buf[DECIMAL64_Bytes*2+1];
Int i, j=0;
if (DECLITEND) {
for (i=0; i<DECIMAL64_Bytes; i++, j+=2) {
sprintf(&buf[j], "%02x", d64->bytes[7-i]);
}
printf(" D64> %s [S:%d Cb:%02x Ec:%02x] LittleEndian\n", buf,
d64->bytes[7]>>7, (d64->bytes[7]>>2)&0x1f,
((d64->bytes[7]&0x3)<<6)| (d64->bytes[6]>>2));
}
else { /* big-endian */
for (i=0; i<DECIMAL64_Bytes; i++, j+=2) {
sprintf(&buf[j], "%02x", d64->bytes[i]);
}
printf(" D64> %s [S:%d Cb:%02x Ec:%02x] BigEndian\n", buf,
decimal64Sign(d64), decimal64Comb(d64), decimal64ExpCon(d64));
}
} /* decimal64Show */
#endif
/* ================================================================== */
/* Shared utility routines and tables */
/* ================================================================== */
/* define and include the conversion tables to use for shared code */
#if DECDPUN==3
#define DEC_DPD2BIN 1
#else
#define DEC_DPD2BCD 1
#endif
#include "decDPD.h" /* lookup tables */
/* The maximum number of decNumberUnits needed for a working copy of */
/* the units array is the ceiling of digits/DECDPUN, where digits is */
/* the maximum number of digits in any of the formats for which this */
/* is used. decimal128.h must not be included in this module, so, as */
/* a very special case, that number is defined as a literal here. */
#define DECMAX754 34
#define DECMAXUNITS ((DECMAX754+DECDPUN-1)/DECDPUN)
/* ------------------------------------------------------------------ */
/* Combination field lookup tables (uInts to save measurable work) */
/* */
/* COMBEXP - 2-bit most-significant-bits of exponent */
/* [11 if an Infinity or NaN] */
/* COMBMSD - 4-bit most-significant-digit */
/* [0=Infinity, 1=NaN if COMBEXP=11] */
/* */
/* Both are indexed by the 5-bit combination field (0-31) */
/* ------------------------------------------------------------------ */
const uInt COMBEXP[32]={0, 0, 0, 0, 0, 0, 0, 0,
1, 1, 1, 1, 1, 1, 1, 1,
2, 2, 2, 2, 2, 2, 2, 2,
0, 0, 1, 1, 2, 2, 3, 3};
const uInt COMBMSD[32]={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, 1};
/* ------------------------------------------------------------------ */
/* decDigitsToDPD -- pack coefficient into DPD form */
/* */
/* dn is the source number (assumed valid, max DECMAX754 digits) */
/* targ is 1, 2, or 4-element uInt array, which the caller must */
/* have cleared to zeros */
/* shift is the number of 0 digits to add on the right (normally 0) */
/* */
/* The coefficient must be known small enough to fit. The full */
/* coefficient is copied, including the leading 'odd' digit. This */
/* digit is retrieved and packed into the combination field by the */
/* caller. */
/* */
/* The target uInts are altered only as necessary to receive the */
/* digits of the decNumber. When more than one uInt is needed, they */
/* are filled from left to right (that is, the uInt at offset 0 will */
/* end up with the least-significant digits). */
/* */
/* shift is used for 'fold-down' padding. */
/* */
/* No error is possible. */
/* ------------------------------------------------------------------ */
#if DECDPUN<=4
/* Constant multipliers for divide-by-power-of five using reciprocal */
/* multiply, after removing powers of 2 by shifting, and final shift */
/* of 17 [we only need up to **4] */
static const uInt multies[]={131073, 26215, 5243, 1049, 210};
/* QUOT10 -- macro to return the quotient of unit u divided by 10**n */
#define QUOT10(u, n) ((((uInt)(u)>>(n))*multies[n])>>17)
#endif
void decDigitsToDPD(const decNumber *dn, uInt *targ, Int shift) {
Int cut; /* work */
Int n; /* output bunch counter */
Int digits=dn->digits; /* digit countdown */
uInt dpd; /* densely packed decimal value */
uInt bin; /* binary value 0-999 */
uInt *uout=targ; /* -> current output uInt */
uInt uoff=0; /* -> current output offset [from right] */
const Unit *inu=dn->lsu; /* -> current input unit */
Unit uar[DECMAXUNITS]; /* working copy of units, iff shifted */
#if DECDPUN!=3 /* not fast path */
Unit in; /* current unit */
#endif
if (shift!=0) { /* shift towards most significant required */
/* shift the units array to the left by pad digits and copy */
/* [this code is a special case of decShiftToMost, which could */
/* be used instead if exposed and the array were copied first] */
const Unit *source; /* .. */
Unit *target, *first; /* .. */
uInt next=0; /* work */
source=dn->lsu+D2U(digits)-1; /* where msu comes from */
target=uar+D2U(digits)-1+D2U(shift);/* where upper part of first cut goes */
cut=DECDPUN-MSUDIGITS(shift); /* where to slice */
if (cut==0) { /* unit-boundary case */
for (; source>=dn->lsu; source--, target--) *target=*source;
}
else {
first=uar+D2U(digits+shift)-1; /* where msu will end up */
for (; source>=dn->lsu; source--, target--) {
/* split the source Unit and accumulate remainder for next */
#if DECDPUN<=4
uInt quot=QUOT10(*source, cut);
uInt rem=*source-quot*DECPOWERS[cut];
next+=quot;
#else
uInt rem=*source%DECPOWERS[cut];
next+=*source/DECPOWERS[cut];
#endif
if (target<=first) *target=(Unit)next; /* write to target iff valid */
next=rem*DECPOWERS[DECDPUN-cut]; /* save remainder for next Unit */
}
} /* shift-move */
/* propagate remainder to one below and clear the rest */
for (; target>=uar; target--) {
*target=(Unit)next;
next=0;
}
digits+=shift; /* add count (shift) of zeros added */
inu=uar; /* use units in working array */
}
/* now densely pack the coefficient into DPD declets */
#if DECDPUN!=3 /* not fast path */
in=*inu; /* current unit */
cut=0; /* at lowest digit */
bin=0; /* [keep compiler quiet] */
#endif
for(n=0; digits>0; n++) { /* each output bunch */
#if DECDPUN==3 /* fast path, 3-at-a-time */
bin=*inu; /* 3 digits ready for convert */
digits-=3; /* [may go negative] */
inu++; /* may need another */
#else /* must collect digit-by-digit */
Unit dig; /* current digit */
Int j; /* digit-in-declet count */
for (j=0; j<3; j++) {
#if DECDPUN<=4
Unit temp=(Unit)((uInt)(in*6554)>>16);
dig=(Unit)(in-X10(temp));
in=temp;
#else
dig=in%10;
in=in/10;
#endif
if (j==0) bin=dig;
else if (j==1) bin+=X10(dig);
else /* j==2 */ bin+=X100(dig);
digits--;
if (digits==0) break; /* [also protects *inu below] */
cut++;
if (cut==DECDPUN) {inu++; in=*inu; cut=0;}
}
#endif
/* here there are 3 digits in bin, or have used all input digits */
dpd=BIN2DPD[bin];
/* write declet to uInt array */
*uout|=dpd<<uoff;
uoff+=10;
if (uoff<32) continue; /* no uInt boundary cross */
uout++;
uoff-=32;
*uout|=dpd>>(10-uoff); /* collect top bits */
} /* n declets */
return;
} /* decDigitsToDPD */
/* ------------------------------------------------------------------ */
/* decDigitsFromDPD -- unpack a format's coefficient */
/* */
/* dn is the target number, with 7, 16, or 34-digit space. */
/* sour is a 1, 2, or 4-element uInt array containing only declets */
/* declets is the number of (right-aligned) declets in sour to */
/* be processed. This may be 1 more than the obvious number in */
/* a format, as any top digit is prefixed to the coefficient */
/* continuation field. It also may be as small as 1, as the */
/* caller may pre-process leading zero declets. */
/* */
/* When doing the 'extra declet' case care is taken to avoid writing */
/* extra digits when there are leading zeros, as these could overflow */
/* the units array when DECDPUN is not 3. */
/* */
/* The target uInts are used only as necessary to process declets */
/* declets into the decNumber. When more than one uInt is needed, */
/* they are used from left to right (that is, the uInt at offset 0 */
/* provides the least-significant digits). */
/* */
/* dn->digits is set, but not the sign or exponent. */
/* No error is possible [the redundant 888 codes are allowed]. */
/* ------------------------------------------------------------------ */
void decDigitsFromDPD(decNumber *dn, const uInt *sour, Int declets) {
uInt dpd; /* collector for 10 bits */
Int n; /* counter */
Unit *uout=dn->lsu; /* -> current output unit */
Unit *last=uout; /* will be unit containing msd */
const uInt *uin=sour; /* -> current input uInt */
uInt uoff=0; /* -> current input offset [from right] */
#if DECDPUN!=3
uInt bcd; /* BCD result */
uInt nibble; /* work */
Unit out=0; /* accumulator */
Int cut=0; /* power of ten in current unit */
#endif
#if DECDPUN>4
uInt const *pow; /* work */
#endif
/* Expand the densely-packed integer, right to left */
for (n=declets-1; n>=0; n--) { /* count down declets of 10 bits */
dpd=*uin>>uoff;
uoff+=10;
if (uoff>32) { /* crossed uInt boundary */
uin++;
uoff-=32;
dpd|=*uin<<(10-uoff); /* get waiting bits */
}
dpd&=0x3ff; /* clear uninteresting bits */
#if DECDPUN==3
if (dpd==0) *uout=0;
else {
*uout=DPD2BIN[dpd]; /* convert 10 bits to binary 0-999 */
last=uout; /* record most significant unit */
}
uout++;
} /* n */
#else /* DECDPUN!=3 */
if (dpd==0) { /* fastpath [e.g., leading zeros] */
/* write out three 0 digits (nibbles); out may have digit(s) */
cut++;
if (cut==DECDPUN) {*uout=out; if (out) {last=uout; out=0;} uout++; cut=0;}
if (n==0) break; /* [as below, works even if MSD=0] */
cut++;
if (cut==DECDPUN) {*uout=out; if (out) {last=uout; out=0;} uout++; cut=0;}
cut++;
if (cut==DECDPUN) {*uout=out; if (out) {last=uout; out=0;} uout++; cut=0;}
continue;
}
bcd=DPD2BCD[dpd]; /* convert 10 bits to 12 bits BCD */
/* now accumulate the 3 BCD nibbles into units */
nibble=bcd & 0x00f;
if (nibble) out=(Unit)(out+nibble*DECPOWERS[cut]);
cut++;
if (cut==DECDPUN) {*uout=out; if (out) {last=uout; out=0;} uout++; cut=0;}
bcd>>=4;
/* if this is the last declet and the remaining nibbles in bcd */
/* are 00 then process no more nibbles, because this could be */
/* the 'odd' MSD declet and writing any more Units would then */
/* overflow the unit array */
if (n==0 && !bcd) break;
nibble=bcd & 0x00f;
if (nibble) out=(Unit)(out+nibble*DECPOWERS[cut]);
cut++;
if (cut==DECDPUN) {*uout=out; if (out) {last=uout; out=0;} uout++; cut=0;}
bcd>>=4;
nibble=bcd & 0x00f;
if (nibble) out=(Unit)(out+nibble*DECPOWERS[cut]);
cut++;
if (cut==DECDPUN) {*uout=out; if (out) {last=uout; out=0;} uout++; cut=0;}
} /* n */
if (cut!=0) { /* some more left over */
*uout=out; /* write out final unit */
if (out) last=uout; /* and note if non-zero */
}
#endif
/* here, last points to the most significant unit with digits; */
/* inspect it to get the final digits count -- this is essentially */
/* the same code as decGetDigits in decNumber.c */
dn->digits=(last-dn->lsu)*DECDPUN+1; /* floor of digits, plus */
/* must be at least 1 digit */
#if DECDPUN>1
if (*last<10) return; /* common odd digit or 0 */
dn->digits++; /* must be 2 at least */
#if DECDPUN>2
if (*last<100) return; /* 10-99 */
dn->digits++; /* must be 3 at least */
#if DECDPUN>3
if (*last<1000) return; /* 100-999 */
dn->digits++; /* must be 4 at least */
#if DECDPUN>4
for (pow=&DECPOWERS[4]; *last>=*pow; pow++) dn->digits++;
#endif
#endif
#endif
#endif
return;
} /*decDigitsFromDPD */
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