Mercurial > hg > CbC > CbC_gcc
annotate libdecnumber/decPacked.c @ 158:494b0b89df80 default tip
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| author | Shinji KONO <kono@ie.u-ryukyu.ac.jp> |
|---|---|
| date | Mon, 25 May 2020 18:13:55 +0900 |
| parents | 1830386684a0 |
| children |
| rev | line source |
|---|---|
| 0 | 1 /* Packed decimal conversion module for the decNumber C Library. |
| 145 | 2 Copyright (C) 2007-2020 Free Software Foundation, Inc. |
| 0 | 3 Contributed by IBM Corporation. Author Mike Cowlishaw. |
| 4 | |
| 5 This file is part of GCC. | |
| 6 | |
| 7 GCC is free software; you can redistribute it and/or modify it under | |
| 8 the terms of the GNU General Public License as published by the Free | |
| 9 Software Foundation; either version 3, or (at your option) any later | |
| 10 version. | |
| 11 | |
| 12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
| 13 WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 15 for more details. | |
| 16 | |
| 17 Under Section 7 of GPL version 3, you are granted additional | |
| 18 permissions described in the GCC Runtime Library Exception, version | |
| 19 3.1, as published by the Free Software Foundation. | |
| 20 | |
| 21 You should have received a copy of the GNU General Public License and | |
| 22 a copy of the GCC Runtime Library Exception along with this program; | |
| 23 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
| 24 <http://www.gnu.org/licenses/>. */ | |
| 25 | |
| 26 /* ------------------------------------------------------------------ */ | |
| 27 /* Packed Decimal conversion module */ | |
| 28 /* ------------------------------------------------------------------ */ | |
|
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29 /* This module comprises the routines for Packed Decimal format */ |
| 0 | 30 /* numbers. Conversions are supplied to and from decNumber, which in */ |
| 31 /* turn supports: */ | |
| 32 /* conversions to and from string */ | |
| 33 /* arithmetic routines */ | |
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34 /* utilities. */ |
| 0 | 35 /* Conversions from decNumber to and from densely packed decimal */ |
| 36 /* formats are provided by the decimal32 through decimal128 modules. */ | |
| 37 /* ------------------------------------------------------------------ */ | |
| 38 | |
| 39 #include <string.h> /* for NULL */ | |
| 40 #include "decNumber.h" /* base number library */ | |
| 41 #include "decPacked.h" /* packed decimal */ | |
| 42 #include "decNumberLocal.h" /* decNumber local types, etc. */ | |
| 43 | |
| 44 /* ------------------------------------------------------------------ */ | |
| 45 /* decPackedFromNumber -- convert decNumber to BCD Packed Decimal */ | |
| 46 /* */ | |
| 47 /* bcd is the BCD bytes */ | |
| 48 /* length is the length of the BCD array */ | |
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49 /* scale is the scale result */ |
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50 /* dn is the decNumber */ |
| 0 | 51 /* returns bcd, or NULL if error */ |
| 52 /* */ | |
| 53 /* The number is converted to a BCD packed decimal byte array, */ | |
| 54 /* right aligned in the bcd array, whose length is indicated by the */ | |
| 55 /* second parameter. The final 4-bit nibble in the array will be a */ | |
| 56 /* sign nibble, C (1100) for + and D (1101) for -. Unused bytes and */ | |
| 57 /* nibbles to the left of the number are set to 0. */ | |
| 58 /* */ | |
| 59 /* scale is set to the scale of the number (this is the exponent, */ | |
| 60 /* negated). To force the number to a specified scale, first use the */ | |
| 61 /* decNumberRescale routine, which will round and change the exponent */ | |
| 62 /* as necessary. */ | |
| 63 /* */ | |
| 64 /* If there is an error (that is, the decNumber has too many digits */ | |
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65 /* to fit in length bytes, or it is a NaN or Infinity), NULL is */ |
| 0 | 66 /* returned and the bcd and scale results are unchanged. Otherwise */ |
| 67 /* bcd is returned. */ | |
| 68 /* ------------------------------------------------------------------ */ | |
| 69 uByte * decPackedFromNumber(uByte *bcd, Int length, Int *scale, | |
| 70 const decNumber *dn) { | |
| 71 const Unit *up=dn->lsu; /* Unit array pointer */ | |
| 72 uByte obyte, *out; /* current output byte, and where it goes */ | |
| 73 Int indigs=dn->digits; /* digits processed */ | |
| 74 uInt cut=DECDPUN; /* downcounter per Unit */ | |
| 75 uInt u=*up; /* work */ | |
| 76 uInt nib; /* .. */ | |
| 77 #if DECDPUN<=4 | |
| 78 uInt temp; /* .. */ | |
| 79 #endif | |
| 80 | |
| 81 if (dn->digits>length*2-1 /* too long .. */ | |
| 82 ||(dn->bits & DECSPECIAL)) return NULL; /* .. or special -- hopeless */ | |
| 83 | |
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84 if (dn->bits&DECNEG) obyte=DECPMINUS; /* set the sign .. */ |
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85 else obyte=DECPPLUS; |
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86 *scale=-dn->exponent; /* .. and scale */ |
| 0 | 87 |
| 88 /* loop from lowest (rightmost) byte */ | |
| 89 out=bcd+length-1; /* -> final byte */ | |
| 90 for (; out>=bcd; out--) { | |
| 91 if (indigs>0) { | |
| 92 if (cut==0) { | |
| 93 up++; | |
| 94 u=*up; | |
| 95 cut=DECDPUN; | |
| 96 } | |
| 97 #if DECDPUN<=4 | |
| 98 temp=(u*6554)>>16; /* fast /10 */ | |
| 99 nib=u-X10(temp); | |
| 100 u=temp; | |
| 101 #else | |
| 102 nib=u%10; /* cannot use *6554 trick :-( */ | |
| 103 u=u/10; | |
| 104 #endif | |
| 105 obyte|=(nib<<4); | |
| 106 indigs--; | |
| 107 cut--; | |
| 108 } | |
| 109 *out=obyte; | |
| 110 obyte=0; /* assume 0 */ | |
| 111 if (indigs>0) { | |
| 112 if (cut==0) { | |
| 113 up++; | |
| 114 u=*up; | |
| 115 cut=DECDPUN; | |
| 116 } | |
| 117 #if DECDPUN<=4 | |
| 118 temp=(u*6554)>>16; /* as above */ | |
| 119 obyte=(uByte)(u-X10(temp)); | |
| 120 u=temp; | |
| 121 #else | |
| 122 obyte=(uByte)(u%10); | |
| 123 u=u/10; | |
| 124 #endif | |
| 125 indigs--; | |
| 126 cut--; | |
| 127 } | |
| 128 } /* loop */ | |
| 129 | |
| 130 return bcd; | |
| 131 } /* decPackedFromNumber */ | |
| 132 | |
| 133 /* ------------------------------------------------------------------ */ | |
| 134 /* decPackedToNumber -- convert BCD Packed Decimal to a decNumber */ | |
| 135 /* */ | |
| 136 /* bcd is the BCD bytes */ | |
| 137 /* length is the length of the BCD array */ | |
| 138 /* scale is the scale associated with the BCD integer */ | |
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139 /* dn is the decNumber [with space for length*2 digits] */ |
| 0 | 140 /* returns dn, or NULL if error */ |
| 141 /* */ | |
| 142 /* The BCD packed decimal byte array, together with an associated */ | |
| 143 /* scale, is converted to a decNumber. The BCD array is assumed full */ | |
| 144 /* of digits, and must be ended by a 4-bit sign nibble in the least */ | |
| 145 /* significant four bits of the final byte. */ | |
| 146 /* */ | |
| 147 /* The scale is used (negated) as the exponent of the decNumber. */ | |
| 148 /* Note that zeros may have a sign and/or a scale. */ | |
| 149 /* */ | |
| 150 /* The decNumber structure is assumed to have sufficient space to */ | |
| 151 /* hold the converted number (that is, up to length*2-1 digits), so */ | |
| 152 /* no error is possible unless the adjusted exponent is out of range, */ | |
| 153 /* no sign nibble was found, or a sign nibble was found before the */ | |
| 154 /* final nibble. In these error cases, NULL is returned and the */ | |
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155 /* decNumber will be 0. */ |
| 0 | 156 /* ------------------------------------------------------------------ */ |
| 157 decNumber * decPackedToNumber(const uByte *bcd, Int length, | |
| 158 const Int *scale, decNumber *dn) { | |
| 159 const uByte *last=bcd+length-1; /* -> last byte */ | |
| 160 const uByte *first; /* -> first non-zero byte */ | |
| 161 uInt nib; /* work nibble */ | |
| 162 Unit *up=dn->lsu; /* output pointer */ | |
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163 Int digits; /* digits count */ |
| 0 | 164 Int cut=0; /* phase of output */ |
| 165 | |
| 166 decNumberZero(dn); /* default result */ | |
| 167 last=&bcd[length-1]; | |
| 168 nib=*last & 0x0f; /* get the sign */ | |
| 169 if (nib==DECPMINUS || nib==DECPMINUSALT) dn->bits=DECNEG; | |
| 170 else if (nib<=9) return NULL; /* not a sign nibble */ | |
| 171 | |
| 172 /* skip leading zero bytes [final byte is always non-zero, due to sign] */ | |
| 173 for (first=bcd; *first==0;) first++; | |
| 174 digits=(last-first)*2+1; /* calculate digits .. */ | |
| 175 if ((*first & 0xf0)==0) digits--; /* adjust for leading zero nibble */ | |
| 176 if (digits!=0) dn->digits=digits; /* count of actual digits [if 0, */ | |
| 177 /* leave as 1] */ | |
| 178 | |
| 179 /* check the adjusted exponent; note that scale could be unbounded */ | |
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180 dn->exponent=-*scale; /* set the exponent */ |
| 0 | 181 if (*scale>=0) { /* usual case */ |
| 182 if ((dn->digits-*scale-1)<-DECNUMMAXE) { /* underflow */ | |
| 183 decNumberZero(dn); | |
| 184 return NULL;} | |
| 185 } | |
| 186 else { /* -ve scale; +ve exponent */ | |
| 187 /* need to be careful to avoid wrap, here, also BADINT case */ | |
| 188 if ((*scale<-DECNUMMAXE) /* overflow even without digits */ | |
| 189 || ((dn->digits-*scale-1)>DECNUMMAXE)) { /* overflow */ | |
| 190 decNumberZero(dn); | |
| 191 return NULL;} | |
| 192 } | |
| 193 if (digits==0) return dn; /* result was zero */ | |
| 194 | |
| 195 /* copy the digits to the number's units, starting at the lsu */ | |
| 196 /* [unrolled] */ | |
| 197 for (;;) { /* forever */ | |
| 198 /* left nibble first */ | |
| 199 nib=(unsigned)(*last & 0xf0)>>4; | |
| 200 /* got a digit, in nib */ | |
| 201 if (nib>9) {decNumberZero(dn); return NULL;} | |
| 202 | |
| 203 if (cut==0) *up=(Unit)nib; | |
| 204 else *up=(Unit)(*up+nib*DECPOWERS[cut]); | |
| 205 digits--; | |
| 206 if (digits==0) break; /* got them all */ | |
| 207 cut++; | |
| 208 if (cut==DECDPUN) { | |
| 209 up++; | |
| 210 cut=0; | |
| 211 } | |
| 212 last--; /* ready for next */ | |
| 213 nib=*last & 0x0f; /* get right nibble */ | |
| 214 if (nib>9) {decNumberZero(dn); return NULL;} | |
| 215 | |
| 216 /* got a digit, in nib */ | |
| 217 if (cut==0) *up=(Unit)nib; | |
| 218 else *up=(Unit)(*up+nib*DECPOWERS[cut]); | |
| 219 digits--; | |
| 220 if (digits==0) break; /* got them all */ | |
| 221 cut++; | |
| 222 if (cut==DECDPUN) { | |
| 223 up++; | |
| 224 cut=0; | |
| 225 } | |
| 226 } /* forever */ | |
| 227 | |
| 228 return dn; | |
| 229 } /* decPackedToNumber */ | |
| 230 |