This is a multi-part message in MIME format. ------=_NextPart_000_001F_01C2D10F.2DD40720 Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: 7bit > Here is what I did to make lookup tables easily... > > Using Excel I made a spreadsheet ... This topic has gotten a surprising amount of interest. To give the result explicitly and also show how easy it is to compute, I wrote a program to generate an MPASM table of logarithmic values. Here is the program: { Program BR * * Write a linear to logarithmic lookup table in PIC * assembler format. } program br; const max_in = 255; {max input value} max_out = 255; {max output value} m = {mult factor between table entries} max_out ** (1.0 / (max_in - 1)); var iv: sys_int_machine_t; {0-N table input value} ov: double; {table output value} begin writeln (' retlw 0 ; 0'); {first entry defined explicitly} ov := 1.0; {init output value for first entry} for iv := 1 to max_in do begin {once for each remaining entry} writeln ( {write this table entry} ' retlw ', round(ov):3, ' ;',iv:3); ov := ov * m {make value for next table entry} end; {back to do next table entry} end. The table generated by this program is attached. -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu ------=_NextPart_000_001F_01C2D10F.2DD40720 Content-Type: application/octet-stream; name="br.inc" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="br.inc" retlw 0 ; 0 retlw 1 ; 1 retlw 1 ; 2 retlw 1 ; 3 retlw 1 ; 4 retlw 1 ; 5 retlw 1 ; 6 retlw 1 ; 7 retlw 1 ; 8 retlw 1 ; 9 retlw 1 ; 10 retlw 1 ; 11 retlw 1 ; 12 retlw 1 ; 13 retlw 1 ; 14 retlw 1 ; 15 retlw 1 ; 16 retlw 1 ; 17 retlw 1 ; 18 retlw 1 ; 19 retlw 2 ; 20 retlw 2 ; 21 retlw 2 ; 22 retlw 2 ; 23 retlw 2 ; 24 retlw 2 ; 25 retlw 2 ; 26 retlw 2 ; 27 retlw 2 ; 28 retlw 2 ; 29 retlw 2 ; 30 retlw 2 ; 31 retlw 2 ; 32 retlw 2 ; 33 retlw 2 ; 34 retlw 2 ; 35 retlw 2 ; 36 retlw 2 ; 37 retlw 2 ; 38 retlw 2 ; 39 retlw 2 ; 40 retlw 2 ; 41 retlw 2 ; 42 retlw 2 ; 43 retlw 3 ; 44 retlw 3 ; 45 retlw 3 ; 46 retlw 3 ; 47 retlw 3 ; 48 retlw 3 ; 49 retlw 3 ; 50 retlw 3 ; 51 retlw 3 ; 52 retlw 3 ; 53 retlw 3 ; 54 retlw 3 ; 55 retlw 3 ; 56 retlw 3 ; 57 retlw 3 ; 58 retlw 4 ; 59 retlw 4 ; 60 retlw 4 ; 61 retlw 4 ; 62 retlw 4 ; 63 retlw 4 ; 64 retlw 4 ; 65 retlw 4 ; 66 retlw 4 ; 67 retlw 4 ; 68 retlw 4 ; 69 retlw 5 ; 70 retlw 5 ; 71 retlw 5 ; 72 retlw 5 ; 73 retlw 5 ; 74 retlw 5 ; 75 retlw 5 ; 76 retlw 5 ; 77 retlw 5 ; 78 retlw 5 ; 79 retlw 6 ; 80 retlw 6 ; 81 retlw 6 ; 82 retlw 6 ; 83 retlw 6 ; 84 retlw 6 ; 85 retlw 6 ; 86 retlw 7 ; 87 retlw 7 ; 88 retlw 7 ; 89 retlw 7 ; 90 retlw 7 ; 91 retlw 7 ; 92 retlw 7 ; 93 retlw 8 ; 94 retlw 8 ; 95 retlw 8 ; 96 retlw 8 ; 97 retlw 8 ; 98 retlw 8 ; 99 retlw 9 ;100 retlw 9 ;101 retlw 9 ;102 retlw 9 ;103 retlw 9 ;104 retlw 10 ;105 retlw 10 ;106 retlw 10 ;107 retlw 10 ;108 retlw 11 ;109 retlw 11 ;110 retlw 11 ;111 retlw 11 ;112 retlw 12 ;113 retlw 12 ;114 retlw 12 ;115 retlw 12 ;116 retlw 13 ;117 retlw 13 ;118 retlw 13 ;119 retlw 13 ;120 retlw 14 ;121 retlw 14 ;122 retlw 14 ;123 retlw 15 ;124 retlw 15 ;125 retlw 15 ;126 retlw 16 ;127 retlw 16 ;128 retlw 16 ;129 retlw 17 ;130 retlw 17 ;131 retlw 17 ;132 retlw 18 ;133 retlw 18 ;134 retlw 19 ;135 retlw 19 ;136 retlw 19 ;137 retlw 20 ;138 retlw 20 ;139 retlw 21 ;140 retlw 21 ;141 retlw 22 ;142 retlw 22 ;143 retlw 23 ;144 retlw 23 ;145 retlw 24 ;146 retlw 24 ;147 retlw 25 ;148 retlw 25 ;149 retlw 26 ;150 retlw 26 ;151 retlw 27 ;152 retlw 28 ;153 retlw 28 ;154 retlw 29 ;155 retlw 29 ;156 retlw 30 ;157 retlw 31 ;158 retlw 31 ;159 retlw 32 ;160 retlw 33 ;161 retlw 34 ;162 retlw 34 ;163 retlw 35 ;164 retlw 36 ;165 retlw 37 ;166 retlw 37 ;167 retlw 38 ;168 retlw 39 ;169 retlw 40 ;170 retlw 41 ;171 retlw 42 ;172 retlw 43 ;173 retlw 44 ;174 retlw 45 ;175 retlw 46 ;176 retlw 47 ;177 retlw 48 ;178 retlw 49 ;179 retlw 50 ;180 retlw 51 ;181 retlw 52 ;182 retlw 53 ;183 retlw 54 ;184 retlw 55 ;185 retlw 57 ;186 retlw 58 ;187 retlw 59 ;188 retlw 60 ;189 retlw 62 ;190 retlw 63 ;191 retlw 65 ;192 retlw 66 ;193 retlw 67 ;194 retlw 69 ;195 retlw 70 ;196 retlw 72 ;197 retlw 74 ;198 retlw 75 ;199 retlw 77 ;200 retlw 79 ;201 retlw 80 ;202 retlw 82 ;203 retlw 84 ;204 retlw 86 ;205 retlw 88 ;206 retlw 89 ;207 retlw 91 ;208 retlw 93 ;209 retlw 96 ;210 retlw 98 ;211 retlw 100 ;212 retlw 102 ;213 retlw 104 ;214 retlw 107 ;215 retlw 109 ;216 retlw 111 ;217 retlw 114 ;218 retlw 116 ;219 retlw 119 ;220 retlw 121 ;221 retlw 124 ;222 retlw 127 ;223 retlw 130 ;224 retlw 133 ;225 retlw 135 ;226 retlw 138 ;227 retlw 141 ;228 retlw 145 ;229 retlw 148 ;230 retlw 151 ;231 retlw 154 ;232 retlw 158 ;233 retlw 161 ;234 retlw 165 ;235 retlw 168 ;236 retlw 172 ;237 retlw 176 ;238 retlw 180 ;239 retlw 184 ;240 retlw 188 ;241 retlw 192 ;242 retlw 196 ;243 retlw 201 ;244 retlw 205 ;245 retlw 210 ;246 retlw 214 ;247 retlw 219 ;248 retlw 224 ;249 retlw 229 ;250 retlw 234 ;251 retlw 239 ;252 retlw 244 ;253 retlw 250 ;254 retlw 255 ;255 ------=_NextPart_000_001F_01C2D10F.2DD40720--