Go to most recent revision | Details | Last modification | View Log | RSS feed
| Rev | Author | Line No. | Line |
|---|---|---|---|
| 359 | serge | 1 | ;***************************************************************************** |
| 2 | ;* |
||
| 3 | ;* Open Watcom Project |
||
| 4 | ;* |
||
| 5 | ;* Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved. |
||
| 6 | ;* |
||
| 7 | ;* ======================================================================== |
||
| 8 | ;* |
||
| 9 | ;* This file contains Original Code and/or Modifications of Original |
||
| 10 | ;* Code as defined in and that are subject to the Sybase Open Watcom |
||
| 11 | ;* Public License version 1.0 (the 'License'). You may not use this file |
||
| 12 | ;* except in compliance with the License. BY USING THIS FILE YOU AGREE TO |
||
| 13 | ;* ALL TERMS AND CONDITIONS OF THE LICENSE. A copy of the License is |
||
| 14 | ;* provided with the Original Code and Modifications, and is also |
||
| 15 | ;* available at www.sybase.com/developer/opensource. |
||
| 16 | ;* |
||
| 17 | ;* The Original Code and all software distributed under the License are |
||
| 18 | ;* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER |
||
| 19 | ;* EXPRESS OR IMPLIED, AND SYBASE AND ALL CONTRIBUTORS HEREBY DISCLAIM |
||
| 20 | ;* ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF |
||
| 21 | ;* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR |
||
| 22 | ;* NON-INFRINGEMENT. Please see the License for the specific language |
||
| 23 | ;* governing rights and limitations under the License. |
||
| 24 | ;* |
||
| 25 | ;* ======================================================================== |
||
| 26 | ;* |
||
| 27 | ;* Description: WHEN YOU FIGURE OUT WHAT THIS FILE DOES, PLEASE |
||
| 28 | ;* DESCRIBE IT HERE! |
||
| 29 | ;* |
||
| 30 | ;***************************************************************************** |
||
| 31 | |||
| 32 | |||
| 33 | ; This module converts a string to long_double |
||
| 34 | ; void __ZBuf2LD( char *buf, long_double *value ); |
||
| 35 | ; |
||
| 36 | include mdef.inc |
||
| 37 | include struct.inc |
||
| 38 | |||
| 39 | modstart bufld386 |
||
| 40 | |||
| 41 | xdefp __ZBuf2LD |
||
| 42 | |||
| 43 | ;<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><> |
||
| 44 | ;<> <> |
||
| 45 | ;<> __ZBuf2LD - convert buffer of significant digits into floating <> |
||
| 46 | ;<> void __ZBuf2LD( char *buf, long_double *value ) <> |
||
| 47 | ;<> <> |
||
| 48 | ;<> input: EAX - address of buffer of significant digits <> |
||
| 49 | ;<> EDX - place to store value <> |
||
| 50 | ;<> output: [EDX] - floating-point number <> |
||
| 51 | ;<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><> |
||
| 52 | |||
| 53 | defpe __ZBuf2LD |
||
| 54 | push EBP ; save EBP |
||
| 55 | push ESI ; save ESI |
||
| 56 | push EDI ; save EDI |
||
| 57 | push ECX ; save ECX |
||
| 58 | push EBX ; save EBX |
||
| 59 | push EDX ; save pointer to result |
||
| 60 | mov ESI,EAX ; get address of buffer |
||
| 61 | sub EDX,EDX ; set 96-bit integer to 0 |
||
| 62 | sub ECX,ECX ; ... |
||
| 63 | sub EBP,EBP ; ... |
||
| 64 | sub EAX,EAX ; zero out EAX |
||
| 65 | _loop ; loop (convert digits into 64-bit int) |
||
| 66 | mov AL,[ESI] ; - get next digit |
||
| 67 | cmp AL,0 ; - quit if at end of buffer |
||
| 68 | _quif e ; - . . . |
||
| 69 | |||
| 70 | ;[] multiply current value in EDX:ECX:EBP by 10 |
||
| 71 | |||
| 72 | mov EDI,EDX ; - save current value |
||
| 73 | mov EBX,ECX ; - ... |
||
| 74 | mov EAX,EBP ; - ... |
||
| 75 | _shl EBP,1 ; - multiply number by 4 |
||
| 76 | _rcl ECX,1 ; - by shifting left 2 places |
||
| 77 | _rcl EDX,1 ; - ... |
||
| 78 | _shl EBP,1 ; - ... |
||
| 79 | _rcl ECX,1 ; - ... |
||
| 80 | _rcl EDX,1 ; - ... |
||
| 81 | add EBP,EAX ; - add original value |
||
| 82 | adc ECX,EBX ; - (this will make it times 5) |
||
| 83 | adc EDX,EDI ; - ... |
||
| 84 | _shl EBP,1 ; - shift left to make it times 10 |
||
| 85 | _rcl ECX,1 ; - ... |
||
| 86 | _rcl EDX,1 ; - ... |
||
| 87 | sub EAX,EAX ; - zero eax |
||
| 88 | mov AL,[ESI] ; - get next digit |
||
| 89 | and AL,0Fh ; - isolate binary digit |
||
| 90 | add EBP,EAX ; - add in current digit |
||
| 91 | adc ECX,0 ; - ... |
||
| 92 | adc EDX,0 ; - ... |
||
| 93 | inc ESI ; - point to next digit in buffer |
||
| 94 | _endloop ; endloop |
||
| 95 | mov EAX,ECX ; get low order word into EAX |
||
| 96 | |||
| 97 | ;[] Turn the integer in EDX:EAX:EBP into a real number |
||
| 98 | |||
| 99 | mov EDI,3FFFh+63+32 ; set exponent |
||
| 100 | call Norm ; convert the 64 bit integer to a float |
||
| 101 | pop EBP ; restore pointer to result |
||
| 102 | mov 4[EBP],EDX ; store result |
||
| 103 | mov 0[EBP],EAX ; ... |
||
| 104 | mov 8[EBP],SI ; ... |
||
| 105 | pop EBX ; restore EBX |
||
| 106 | pop ECX ; restore ECX |
||
| 107 | pop EDI ; restore EDI |
||
| 108 | pop ESI ; restore ESI |
||
| 109 | pop EBP ; restore EBP |
||
| 110 | ret ; return to caller |
||
| 111 | endproc __ZBuf2LD |
||
| 112 | |||
| 113 | |||
| 114 | ;[] Norm normalizes an unsigned real in EDX:EAX:EBP i.e grab top 64 bits |
||
| 115 | ;[] expects the exponent to be in EDI. |
||
| 116 | ;[] SI contains the new exponent |
||
| 117 | |||
| 118 | Norm proc near ; normalize floating point number |
||
| 119 | sub ESI,ESI ; clear out SI |
||
| 120 | or ESI,EAX ; see if the integer is zero |
||
| 121 | or ESI,EDX ; ... |
||
| 122 | or ESI,EBP ; ... |
||
| 123 | _if ne ; if number is non-zero |
||
| 124 | or EDX,EDX ; - see if high word is 0 |
||
| 125 | _if e ; - if high word is 0 |
||
| 126 | mov EDX,EAX ; - - shift by 32-bits |
||
| 127 | mov EAX,EBP ; - - ... |
||
| 128 | sub EBP,EBP ; - - ... |
||
| 129 | sub EDI,32 ; - - adjust exponent by 32 |
||
| 130 | _endif ; - endif |
||
| 131 | or EDX,EDX ; - see if high word is 0 |
||
| 132 | _if e ; - if high word is 0 |
||
| 133 | mov EDX,EAX ; - - shift by 32-bits |
||
| 134 | mov EAX,EBP ; - - ... |
||
| 135 | sub EBP,EBP ; - - ... |
||
| 136 | sub EDI,32 ; - - adjust exponent by 32 |
||
| 137 | _endif ; - endif |
||
| 138 | _loop ; - loop |
||
| 139 | or EDX,EDX ; - - quit if high bit is on |
||
| 140 | _quif s ; - - ... |
||
| 141 | dec EDI ; - - decrement exponent |
||
| 142 | _shl EBP,1 ; - - shift integer left by 1 bit |
||
| 143 | _rcl EAX,1 ; - - ... |
||
| 144 | _rcl EDX,1 ; - - ... |
||
| 145 | _endloop ; - endloop |
||
| 146 | _shl EBP,1 ; - get top bit of extra word |
||
| 147 | adc EAX,0 ; - round up |
||
| 148 | adc EDX,0 ; - ... |
||
| 149 | _if c ; - if carry out the top |
||
| 150 | rcr EDX,1 ; - - shift fraction back 1 |
||
| 151 | inc EDI ; - - increment exponent |
||
| 152 | _endif ; - endif |
||
| 153 | mov ESI,EDI ; - get exponent |
||
| 154 | _endif ; endif |
||
| 155 | ret ; return |
||
| 156 | endproc Norm |
||
| 157 | |||
| 158 | endmod |
||
| 159 | end |