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Diffstat (limited to 'src/libdecnumber/dpd/decimal128.c')
| -rw-r--r-- | src/libdecnumber/dpd/decimal128.c | 564 |
1 files changed, 564 insertions, 0 deletions
diff --git a/src/libdecnumber/dpd/decimal128.c b/src/libdecnumber/dpd/decimal128.c new file mode 100644 index 0000000..7551b7c --- /dev/null +++ b/src/libdecnumber/dpd/decimal128.c @@ -0,0 +1,564 @@ +/* Decimal 128-bit format module for the decNumber C Library. + Copyright (C) 2005, 2007 Free Software Foundation, Inc. + Contributed by IBM Corporation. Author Mike Cowlishaw. + + This file is part of GCC. + + GCC is free software; you can redistribute it and/or modify it under + the terms of the GNU General Public License as published by the Free + Software Foundation; either version 2, or (at your option) any later + version. + + In addition to the permissions in the GNU General Public License, + the Free Software Foundation gives you unlimited permission to link + the compiled version of this file into combinations with other + programs, and to distribute those combinations without any + restriction coming from the use of this file. (The General Public + License restrictions do apply in other respects; for example, they + cover modification of the file, and distribution when not linked + into a combine executable.) + + GCC is distributed in the hope that it will be useful, but WITHOUT ANY + WARRANTY; without even the implied warranty of MERCHANTABILITY or + FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + for more details. + + You should have received a copy of the GNU General Public License + along with GCC; see the file COPYING. If not, write to the Free + Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA + 02110-1301, USA. */ + +/* ------------------------------------------------------------------ */ +/* Decimal 128-bit format module */ +/* ------------------------------------------------------------------ */ +/* This module comprises the routines for decimal128 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 "libdecnumber/dconfig.h" +#define DECNUMDIGITS 34 /* make decNumbers with space for 34 */ +#include "libdecnumber/decNumber.h" +#include "libdecnumber/decNumberLocal.h" +#include "libdecnumber/dpd/decimal128.h" + +/* Utility routines and tables [in decimal64.c] */ +extern const uInt COMBEXP[32], COMBMSD[32]; +extern const uByte BIN2CHAR[4001]; + +extern void decDigitsFromDPD(decNumber *, const uInt *, Int); +extern void decDigitsToDPD(const decNumber *, uInt *, Int); + +#if DECTRACE || DECCHECK +void decimal128Show(const decimal128 *); /* 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)) + +/* ------------------------------------------------------------------ */ +/* decimal128FromNumber -- convert decNumber to decimal128 */ +/* */ +/* ds is the target decimal128 */ +/* 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 DECIMAL128_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. */ +/* ------------------------------------------------------------------ */ +decimal128 * decimal128FromNumber(decimal128 *d128, const decNumber *dn, + decContext *set) { + uInt status=0; /* status accumulator */ + Int ae; /* adjusted exponent */ + decNumber dw; /* work */ + decContext dc; /* .. */ + uInt *pu; /* .. */ + uInt comb, exp; /* .. */ + uInt targar[4]={0,0,0,0}; /* target 128-bit */ + #define targhi targar[3] /* name the word with the sign */ + #define targmh targar[2] /* name the words */ + #define targml targar[1] /* .. */ + #define targlo targar[0] /* .. */ + + /* 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 */ + /* decimal128] */ + ae=dn->exponent+dn->digits-1; /* [0 if special] */ + if (dn->digits>DECIMAL128_Pmax /* too many digits */ + || ae>DECIMAL128_Emax /* likely overflow */ + || ae<DECIMAL128_Emin) { /* likely underflow */ + decContextDefault(&dc, DEC_INIT_DECIMAL128); /* [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<DECIMAL128_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<-DECIMAL128_Bias) { + exp=0; /* low clamp */ + status|=DEC_Clamped; + } + else { + exp=dn->exponent+DECIMAL128_Bias; /* bias exponent */ + if (exp>DECIMAL128_Ehigh) { /* top clamp */ + exp=DECIMAL128_Ehigh; + status|=DEC_Clamped; + } + } + comb=(exp>>9) & 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+DECIMAL128_Bias); /* bias exponent */ + if (exp>DECIMAL128_Ehigh) { /* fold-down case */ + pad=exp-DECIMAL128_Ehigh; + exp=DECIMAL128_Ehigh; /* [to maximum] */ + status|=DEC_Clamped; + } + + /* [fastpath for common case is not a win, here] */ + decDigitsToDPD(dn, targar, pad); + /* save and clear the top digit */ + msd=targhi>>14; + targhi&=0x00003fff; + + /* create the combination field */ + if (msd>=8) comb=0x18 | ((exp>>11) & 0x06) | (msd & 0x01); + else comb=((exp>>9) & 0x18) | msd; + } + targhi|=comb<<26; /* add combination field .. */ + targhi|=(exp&0xfff)<<14; /* .. and exponent continuation */ + } /* finite */ + + if (dn->bits&DECNEG) targhi|=0x80000000; /* add sign bit */ + + /* now write to storage; this is endian */ + pu=(uInt *)d128->bytes; /* overlay */ + if (DECLITEND) { + pu[0]=targlo; /* directly store the low int */ + pu[1]=targml; /* then the mid-low */ + pu[2]=targmh; /* then the mid-high */ + pu[3]=targhi; /* then the high int */ + } + else { + pu[0]=targhi; /* directly store the high int */ + pu[1]=targmh; /* then the mid-high */ + pu[2]=targml; /* then the mid-low */ + pu[3]=targlo; /* then the low int */ + } + + if (status!=0) decContextSetStatus(set, status); /* pass on status */ + /* decimal128Show(d128); */ + return d128; + } /* decimal128FromNumber */ + +/* ------------------------------------------------------------------ */ +/* decimal128ToNumber -- convert decimal128 to decNumber */ +/* d128 is the source decimal128 */ +/* dn is the target number, with appropriate space */ +/* No error is possible. */ +/* ------------------------------------------------------------------ */ +decNumber * decimal128ToNumber(const decimal128 *d128, decNumber *dn) { + uInt msd; /* coefficient MSD */ + uInt exp; /* exponent top two bits */ + uInt comb; /* combination field */ + const uInt *pu; /* work */ + Int need; /* .. */ + uInt sourar[4]; /* source 128-bit */ + #define sourhi sourar[3] /* name the word with the sign */ + #define sourmh sourar[2] /* and the mid-high word */ + #define sourml sourar[1] /* and the mod-low word */ + #define sourlo sourar[0] /* and the lowest word */ + + /* load source from storage; this is endian */ + pu=(const uInt *)d128->bytes; /* overlay */ + if (DECLITEND) { + sourlo=pu[0]; /* directly load the low int */ + sourml=pu[1]; /* then the mid-low */ + sourmh=pu[2]; /* then the mid-high */ + sourhi=pu[3]; /* then the high int */ + } + else { + sourhi=pu[0]; /* directly load the high int */ + sourmh=pu[1]; /* then the mid-high */ + sourml=pu[2]; /* then the mid-low */ + sourlo=pu[3]; /* 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<<12)+((sourhi>>14)&0xfff)-DECIMAL128_Bias; /* unbiased */ + } + + /* get the coefficient */ + sourhi&=0x00003fff; /* clean coefficient continuation */ + if (msd) { /* non-zero msd */ + sourhi|=msd<<14; /* prefix to coefficient */ + need=12; /* process 12 declets */ + } + else { /* msd=0 */ + if (sourhi) need=11; /* declets to process */ + else if (sourmh) need=10; + else if (sourml) need=7; + else if (sourlo) need=4; + else return dn; /* easy: coefficient is 0 */ + } /*msd=0 */ + + decDigitsFromDPD(dn, sourar, need); /* process declets */ + /* decNumberShow(dn); */ + return dn; + } /* decimal128ToNumber */ + +/* ------------------------------------------------------------------ */ +/* to-scientific-string -- conversion to numeric string */ +/* to-engineering-string -- conversion to numeric string */ +/* */ +/* decimal128ToString(d128, string); */ +/* decimal128ToEngString(d128, string); */ +/* */ +/* d128 is the decimal128 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 * decimal128ToEngString(const decimal128 *d128, char *string){ + decNumber dn; /* work */ + decimal128ToNumber(d128, &dn); + decNumberToEngString(&dn, string); + return string; + } /* decimal128ToEngString */ + +char * decimal128ToString(const decimal128 *d128, 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 uInt *pu; /* work */ + char *s, *t; /* .. (source, target) */ + Int dpd; /* .. */ + Int pre, e; /* .. */ + const uByte *u; /* .. */ + + uInt sourar[4]; /* source 128-bit */ + #define sourhi sourar[3] /* name the word with the sign */ + #define sourmh sourar[2] /* and the mid-high word */ + #define sourml sourar[1] /* and the mod-low word */ + #define sourlo sourar[0] /* and the lowest word */ + + /* load source from storage; this is endian */ + pu=(const uInt *)d128->bytes; /* overlay */ + if (DECLITEND) { + sourlo=pu[0]; /* directly load the low int */ + sourml=pu[1]; /* then the mid-low */ + sourmh=pu[2]; /* then the mid-high */ + sourhi=pu[3]; /* then the high int */ + } + else { + sourhi=pu[0]; /* directly load the high int */ + sourmh=pu[1]; /* then the mid-high */ + sourml=pu[2]; /* then the mid-low */ + sourlo=pu[3]; /* 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 && sourml==0 && sourmh==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<<12)+((sourhi>>14)&0xfff)-DECIMAL128_Bias; /* unbiased */ + + /* convert 34 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>>4)&0x3ff; /* declet 1 */ + dpd2char; + dpd=((sourhi&0xf)<<6) | (sourmh>>26); /* declet 2 */ + dpd2char; + dpd=(sourmh>>16)&0x3ff; /* declet 3 */ + dpd2char; + dpd=(sourmh>>6)&0x3ff; /* declet 4 */ + dpd2char; + dpd=((sourmh&0x3f)<<4) | (sourml>>28); /* declet 5 */ + dpd2char; + dpd=(sourml>>18)&0x3ff; /* declet 6 */ + dpd2char; + dpd=(sourml>>8)&0x3ff; /* declet 7 */ + dpd2char; + dpd=((sourml&0xff)<<2) | (sourlo>>30); /* declet 8 */ + dpd2char; + dpd=(sourlo>>20)&0x3ff; /* declet 9 */ + dpd2char; + dpd=(sourlo>>10)&0x3ff; /* declet 10 */ + dpd2char; + dpd=(sourlo)&0x3ff; /* declet 11 */ + 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 4 digits */ + if (e!=0) { + *c++='E'; /* starts with E */ + *c++='+'; /* assume positive */ + if (e<0) { + *(c-1)='-'; /* oops, need '-' */ + e=-e; /* uInt, please */ + } + if (e<1000) { /* 3 (or fewer) digits case */ + u=&BIN2CHAR[e*4]; /* -> length byte */ + memcpy(c, u+4-*u, 4); /* copy fixed 4 characters [is safe] */ + c+=*u; /* bump pointer appropriately */ + } + else { /* 4-digits */ + Int thou=((e>>3)*1049)>>17; /* e/1000 */ + Int rem=e-(1000*thou); /* e%1000 */ + *c++='0'+(char)thou; + u=&BIN2CHAR[rem*4]; /* -> length byte */ + memcpy(c, u+1, 4); /* copy fixed 3+1 characters [is safe] */ + c+=3; /* bump pointer, always 3 digits */ + } + } + *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; + } /* decimal128ToString */ + +/* ------------------------------------------------------------------ */ +/* to-number -- conversion from numeric string */ +/* */ +/* decimal128FromString(result, string, set); */ +/* */ +/* result is the decimal128 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 decimal128 NaN. */ +/* ------------------------------------------------------------------ */ +decimal128 * decimal128FromString(decimal128 *result, const char *string, + decContext *set) { + decContext dc; /* work */ + decNumber dn; /* .. */ + + decContextDefault(&dc, DEC_INIT_DECIMAL128); /* no traps, please */ + dc.round=set->round; /* use supplied rounding */ + + decNumberFromString(&dn, string, &dc); /* will round if needed */ + decimal128FromNumber(result, &dn, &dc); + if (dc.status!=0) { /* something happened */ + decContextSetStatus(set, dc.status); /* .. pass it on */ + } + return result; + } /* decimal128FromString */ + +/* ------------------------------------------------------------------ */ +/* decimal128IsCanonical -- test whether encoding is canonical */ +/* d128 is the source decimal128 */ +/* returns 1 if the encoding of d128 is canonical, 0 otherwise */ +/* No error is possible. */ +/* ------------------------------------------------------------------ */ +uint32_t decimal128IsCanonical(const decimal128 *d128) { + decNumber dn; /* work */ + decimal128 canon; /* .. */ + decContext dc; /* .. */ + decContextDefault(&dc, DEC_INIT_DECIMAL128); + decimal128ToNumber(d128, &dn); + decimal128FromNumber(&canon, &dn, &dc);/* canon will now be canonical */ + return memcmp(d128, &canon, DECIMAL128_Bytes)==0; + } /* decimal128IsCanonical */ + +/* ------------------------------------------------------------------ */ +/* decimal128Canonical -- copy an encoding, ensuring it is canonical */ +/* d128 is the source decimal128 */ +/* result is the target (may be the same decimal128) */ +/* returns result */ +/* No error is possible. */ +/* ------------------------------------------------------------------ */ +decimal128 * decimal128Canonical(decimal128 *result, const decimal128 *d128) { + decNumber dn; /* work */ + decContext dc; /* .. */ + decContextDefault(&dc, DEC_INIT_DECIMAL128); + decimal128ToNumber(d128, &dn); + decimal128FromNumber(result, &dn, &dc);/* result will now be canonical */ + return result; + } /* decimal128Canonical */ + +#if DECTRACE || DECCHECK +/* Macros for accessing decimal128 fields. These assume the argument + is a reference (pointer) to the decimal128 structure, and the + decimal128 is in network byte order (big-endian) */ +/* Get sign */ +#define decimal128Sign(d) ((unsigned)(d)->bytes[0]>>7) + +/* Get combination field */ +#define decimal128Comb(d) (((d)->bytes[0] & 0x7c)>>2) + +/* Get exponent continuation [does not remove bias] */ +#define decimal128ExpCon(d) ((((d)->bytes[0] & 0x03)<<10) \ + | ((unsigned)(d)->bytes[1]<<2) \ + | ((unsigned)(d)->bytes[2]>>6)) + +/* Set sign [this assumes sign previously 0] */ +#define decimal128SetSign(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 decimal128SetExpCon(d, e) { \ + (d)->bytes[0]|=(uint8_t)((e)>>10); \ + (d)->bytes[1] =(uint8_t)(((e)&0x3fc)>>2); \ + (d)->bytes[2]|=(uint8_t)(((e)&0x03)<<6);} + +/* ------------------------------------------------------------------ */ +/* decimal128Show -- display a decimal128 in hexadecimal [debug aid] */ +/* d128 -- the number to show */ +/* ------------------------------------------------------------------ */ +/* Also shows sign/cob/expconfields extracted */ +void decimal128Show(const decimal128 *d128) { + char buf[DECIMAL128_Bytes*2+1]; + Int i, j=0; + + if (DECLITEND) { + for (i=0; i<DECIMAL128_Bytes; i++, j+=2) { + sprintf(&buf[j], "%02x", d128->bytes[15-i]); + } + printf(" D128> %s [S:%d Cb:%02x Ec:%02x] LittleEndian\n", buf, + d128->bytes[15]>>7, (d128->bytes[15]>>2)&0x1f, + ((d128->bytes[15]&0x3)<<10)|(d128->bytes[14]<<2)| + (d128->bytes[13]>>6)); + } + else { + for (i=0; i<DECIMAL128_Bytes; i++, j+=2) { + sprintf(&buf[j], "%02x", d128->bytes[i]); + } + printf(" D128> %s [S:%d Cb:%02x Ec:%02x] BigEndian\n", buf, + decimal128Sign(d128), decimal128Comb(d128), + decimal128ExpCon(d128)); + } + } /* decimal128Show */ +#endif |
