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- /* Decimal 64-bit format module for the decNumber C Library.
- Copyright (C) 2005-2022 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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