| /* Decimal 32-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 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 "qemu/osdep.h" |
| |
| #include "libdecnumber/dconfig.h" |
| #define DECNUMDIGITS 7 /* make decNumbers with space for 7 */ |
| #include "libdecnumber/decNumber.h" |
| #include "libdecnumber/decNumberLocal.h" |
| #include "libdecnumber/dpd/decimal32.h" |
| |
| /* Utility tables and routines [in decimal64.c] */ |
| extern const uInt COMBEXP[32], COMBMSD[32]; |
| 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 *pu; /* .. */ |
| uInt comb, exp; /* .. */ |
| 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 */ |
| pu=(uInt *)d32->bytes; /* overlay */ |
| *pu=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 */ |
| const uInt *pu; /* work */ |
| |
| /* load source from storage; this is endian */ |
| pu=(const uInt *)d32->bytes; /* overlay */ |
| sour=*pu; /* 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 uInt *pu; /* work */ |
| const uByte *u; /* .. */ |
| char *s, *t; /* .. (source, target) */ |
| Int dpd; /* .. */ |
| Int pre, e; /* .. */ |
| uInt sour; /* source 32-bit */ |
| |
| /* load source from storage; this is endian */ |
| pu=(const uInt *)d32->bytes; /* overlay */ |
| sour=*pu; /* 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. */ |
| /* ------------------------------------------------------------------ */ |
| uint32_t 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]|=(uint8_t)((e)>>4); \ |
| (d)->bytes[1]|=(uint8_t)(((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 |
