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Diffstat (limited to 'libdecnumber/dpd/decimal64.c')
| -rw-r--r-- | libdecnumber/dpd/decimal64.c | 846 |
1 files changed, 846 insertions, 0 deletions
diff --git a/libdecnumber/dpd/decimal64.c b/libdecnumber/dpd/decimal64.c new file mode 100644 index 000000000..d5153a2b1 --- /dev/null +++ b/libdecnumber/dpd/decimal64.c @@ -0,0 +1,846 @@ +/* Decimal 64-bit format module for the decNumber C Library. + Copyright (C) 2005, 2007, 2009 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 */ |