| /* ------------------------------------------------------------------ */ | |
| /* Decimal 32-bit format module */ | |
| /* ------------------------------------------------------------------ */ | |
| /* Copyright (c) IBM Corporation, 2000, 2008. All rights reserved. */ | |
| /* */ | |
| /* This software is made available under the terms of the */ | |
| /* ICU License -- ICU 1.8.1 and later. */ | |
| /* */ | |
| /* The description and User's Guide ("The decNumber C Library") for */ | |
| /* this software is called decNumber.pdf. This document is */ | |
| /* available, together with arithmetic and format specifications, */ | |
| /* testcases, and Web links, on the General Decimal Arithmetic page. */ | |
| /* */ | |
| /* Please send comments, suggestions, and corrections to the author: */ | |
| /* mfc@uk.ibm.com */ | |
| /* Mike Cowlishaw, IBM Fellow */ | |
| /* IBM UK, PO Box 31, Birmingham Road, Warwick CV34 5JL, UK */ | |
| /* ------------------------------------------------------------------ */ | |
| /* 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] | |
| #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] */ | |
| // DPD2BIN and the reverse are renamed to prevent link-time conflict | |
| // if decQuad is also built in the same executable | |
| #define DPD2BIN DPD2BINx | |
| #define BIN2DPD BIN2DPDx | |
| 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 |