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[/] [openrisc/] [trunk/] [gnu-src/] [gdb-7.2/] [libdecnumber/] [dpd/] [decimal32.c] - Rev 527
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/* Decimal 32-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 32-bit format module */ /* ------------------------------------------------------------------ */ /* This module comprises the routines for decimal32 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 7 /* make decNumbers with space for 7 */ #include "decNumber.h" /* base number library */ #include "decNumberLocal.h" /* decNumber local types, etc. */ #include "decimal32.h" /* our primary include */ /* Utility tables and routines [in decimal64.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 decDigitsToDPD(const decNumber *, uInt *, Int); extern void decDigitsFromDPD(decNumber *, const uInt *, Int); #if DECTRACE || DECCHECK void decimal32Show(const decimal32 *); /* 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)) /* ------------------------------------------------------------------ */ /* decimal32FromNumber -- convert decNumber to decimal32 */ /* */ /* ds is the target decimal32 */ /* 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 DECIMAL32_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. */ /* ------------------------------------------------------------------ */ decimal32 * decimal32FromNumber(decimal32 *d32, 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 targ=0; /* target 32-bit */ /* 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 */ /* decimal32] */ ae=dn->exponent+dn->digits-1; /* [0 if special] */ if (dn->digits>DECIMAL32_Pmax /* too many digits */ || ae>DECIMAL32_Emax /* likely overflow */ || ae<DECIMAL32_Emin) { /* likely underflow */ decContextDefault(&dc, DEC_INIT_DECIMAL32); /* [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) targ=DECIMAL_Inf<<24; else { /* sNaN or qNaN */ if ((*dn->lsu!=0 || dn->digits>1) /* non-zero coefficient */ && (dn->digits<DECIMAL32_Pmax)) { /* coefficient fits */ decDigitsToDPD(dn, &targ, 0); } if (dn->bits&DECNAN) targ|=DECIMAL_NaN<<24; else targ|=DECIMAL_sNaN<<24; } /* a NaN */ } /* special */ else { /* is finite */ if (decNumberIsZero(dn)) { /* is a zero */ /* set and clamp exponent */ if (dn->exponent<-DECIMAL32_Bias) { exp=0; /* low clamp */ status|=DEC_Clamped; } else { exp=dn->exponent+DECIMAL32_Bias; /* bias exponent */ if (exp>DECIMAL32_Ehigh) { /* top clamp */ exp=DECIMAL32_Ehigh; status|=DEC_Clamped; } } comb=(exp>>3) & 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+DECIMAL32_Bias); /* bias exponent */ if (exp>DECIMAL32_Ehigh) { /* fold-down case */ pad=exp-DECIMAL32_Ehigh; exp=DECIMAL32_Ehigh; /* [to maximum] */ status|=DEC_Clamped; } /* fastpath common case */ if (DECDPUN==3 && pad==0) { targ=BIN2DPD[dn->lsu[0]]; if (dn->digits>3) targ|=(uInt)(BIN2DPD[dn->lsu[1]])<<10; msd=(dn->digits==7 ? dn->lsu[2] : 0); } else { /* general case */ decDigitsToDPD(dn, &targ, pad); /* save and clear the top digit */ msd=targ>>20; targ&=0x000fffff; } /* create the combination field */ if (msd>=8) comb=0x18 | ((exp>>5) & 0x06) | (msd & 0x01); else comb=((exp>>3) & 0x18) | msd; } targ|=comb<<26; /* add combination field .. */ targ|=(exp&0x3f)<<20; /* .. and exponent continuation */ } /* finite */ if (dn->bits&DECNEG) targ|=0x80000000; /* add sign bit */ /* now write to storage; this is endian */ UBFROMUI(d32->bytes, targ); /* directly store the int */ if (status!=0) decContextSetStatus(set, status); /* pass on status */ /* decimal32Show(d32); */ return d32; } /* decimal32FromNumber */ /* ------------------------------------------------------------------ */ /* decimal32ToNumber -- convert decimal32 to decNumber */ /* d32 is the source decimal32 */ /* dn is the target number, with appropriate space */ /* No error is possible. */ /* ------------------------------------------------------------------ */ decNumber * decimal32ToNumber(const decimal32 *d32, decNumber *dn) { uInt msd; /* coefficient MSD */ uInt exp; /* exponent top two bits */ uInt comb; /* combination field */ uInt sour; /* source 32-bit */ uInt uiwork; /* for macros */ /* load source from storage; this is endian */ sour=UBTOUI(d32->bytes); /* directly load the int */ comb=(sour>>26)&0x1f; /* combination field */ decNumberZero(dn); /* clean number */ if (sour&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 (sour&0x02000000) dn->bits|=DECSNAN; else dn->bits|=DECNAN; msd=0; /* no top digit */ } else { /* is a finite number */ dn->exponent=(exp<<6)+((sour>>20)&0x3f)-DECIMAL32_Bias; /* unbiased */ } /* get the coefficient */ sour&=0x000fffff; /* clean coefficient continuation */ if (msd) { /* non-zero msd */ sour|=msd<<20; /* prefix to coefficient */ decDigitsFromDPD(dn, &sour, 3); /* process 3 declets */ return dn; } /* msd=0 */ if (!sour) return dn; /* easy: coefficient is 0 */ if (sour&0x000ffc00) /* need 2 declets? */ decDigitsFromDPD(dn, &sour, 2); /* process 2 declets */ else decDigitsFromDPD(dn, &sour, 1); /* process 1 declet */ return dn; } /* decimal32ToNumber */ /* ------------------------------------------------------------------ */ /* to-scientific-string -- conversion to numeric string */ /* to-engineering-string -- conversion to numeric string */ /* */ /* decimal32ToString(d32, string); */ /* decimal32ToEngString(d32, string); */ /* */ /* d32 is the decimal32 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 * decimal32ToEngString(const decimal32 *d32, char *string){ decNumber dn; /* work */ decimal32ToNumber(d32, &dn); decNumberToEngString(&dn, string); return string; } /* decimal32ToEngString */ char * decimal32ToString(const decimal32 *d32, 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 sour; /* source 32-bit */ /* load source from storage; this is endian */ sour=UBTOUI(d32->bytes); /* directly load the int */ c=string; /* where result will go */ if (((Int)sour)<0) *c++='-'; /* handle sign */ comb=(sour>>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 (sour&0x02000000) *c++='s'; /* sNaN */ strcpy(c, "NaN"); /* complete word */ c+=3; /* step past */ if ((sour&0x000fffff)==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<<6)+((sour>>20)&0x3f)-DECIMAL32_Bias; /* unbiased */ /* convert 7 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=(sour>>10)&0x3ff; /* declet 1 */ dpd2char; dpd=(sour)&0x3ff; /* declet 2 */ 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 (E-101 case) */ 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; } /* decimal32ToString */ /* ------------------------------------------------------------------ */ /* to-number -- conversion from numeric string */ /* */ /* decimal32FromString(result, string, set); */ /* */ /* result is the decimal32 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 decimal32 NaN. */ /* ------------------------------------------------------------------ */ decimal32 * decimal32FromString(decimal32 *result, const char *string, decContext *set) { decContext dc; /* work */ decNumber dn; /* .. */ decContextDefault(&dc, DEC_INIT_DECIMAL32); /* no traps, please */ dc.round=set->round; /* use supplied rounding */ decNumberFromString(&dn, string, &dc); /* will round if needed */ decimal32FromNumber(result, &dn, &dc); if (dc.status!=0) { /* something happened */ decContextSetStatus(set, dc.status); /* .. pass it on */ } return result; } /* decimal32FromString */ /* ------------------------------------------------------------------ */ /* decimal32IsCanonical -- test whether encoding is canonical */ /* d32 is the source decimal32 */ /* returns 1 if the encoding of d32 is canonical, 0 otherwise */ /* No error is possible. */ /* ------------------------------------------------------------------ */ uInt decimal32IsCanonical(const decimal32 *d32) { decNumber dn; /* work */ decimal32 canon; /* .. */ decContext dc; /* .. */ decContextDefault(&dc, DEC_INIT_DECIMAL32); decimal32ToNumber(d32, &dn); decimal32FromNumber(&canon, &dn, &dc);/* canon will now be canonical */ return memcmp(d32, &canon, DECIMAL32_Bytes)==0; } /* decimal32IsCanonical */ /* ------------------------------------------------------------------ */ /* decimal32Canonical -- copy an encoding, ensuring it is canonical */ /* d32 is the source decimal32 */ /* result is the target (may be the same decimal32) */ /* returns result */ /* No error is possible. */ /* ------------------------------------------------------------------ */ decimal32 * decimal32Canonical(decimal32 *result, const decimal32 *d32) { decNumber dn; /* work */ decContext dc; /* .. */ decContextDefault(&dc, DEC_INIT_DECIMAL32); decimal32ToNumber(d32, &dn); decimal32FromNumber(result, &dn, &dc);/* result will now be canonical */ return result; } /* decimal32Canonical */ #if DECTRACE || DECCHECK /* Macros for accessing decimal32 fields. These assume the argument is a reference (pointer) to the decimal32 structure, and the decimal32 is in network byte order (big-endian) */ /* Get sign */ #define decimal32Sign(d) ((unsigned)(d)->bytes[0]>>7) /* Get combination field */ #define decimal32Comb(d) (((d)->bytes[0] & 0x7c)>>2) /* Get exponent continuation [does not remove bias] */ #define decimal32ExpCon(d) ((((d)->bytes[0] & 0x03)<<4) \ | ((unsigned)(d)->bytes[1]>>4)) /* Set sign [this assumes sign previously 0] */ #define decimal32SetSign(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 decimal32SetExpCon(d, e) { \ (d)->bytes[0]|=(uByte)((e)>>4); \ (d)->bytes[1]|=(uByte)(((e)&0x0F)<<4);} /* ------------------------------------------------------------------ */ /* decimal32Show -- display a decimal32 in hexadecimal [debug aid] */ /* d32 -- the number to show */ /* ------------------------------------------------------------------ */ /* Also shows sign/cob/expconfields extracted - valid bigendian only */ void decimal32Show(const decimal32 *d32) { char buf[DECIMAL32_Bytes*2+1]; Int i, j=0; if (DECLITEND) { for (i=0; i<DECIMAL32_Bytes; i++, j+=2) { sprintf(&buf[j], "%02x", d32->bytes[3-i]); } printf(" D32> %s [S:%d Cb:%02x Ec:%02x] LittleEndian\n", buf, d32->bytes[3]>>7, (d32->bytes[3]>>2)&0x1f, ((d32->bytes[3]&0x3)<<4)| (d32->bytes[2]>>4)); } else { for (i=0; i<DECIMAL32_Bytes; i++, j+=2) { sprintf(&buf[j], "%02x", d32->bytes[i]); } printf(" D32> %s [S:%d Cb:%02x Ec:%02x] BigEndian\n", buf, decimal32Sign(d32), decimal32Comb(d32), decimal32ExpCon(d32)); } } /* decimal32Show */ #endif
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