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1a4a6eb445
Libbase should keep its RAM usage to a minimum as it is meant to be executed before the SDRAM is up and running. (Having lots of code is OK though as we XIP from the flash)
84 lines
1.6 KiB
C
84 lines
1.6 KiB
C
/* atof.c: converts an ASCII string to float
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Copyright (C) 2003 Jesus Calvino-Fraga, jesusc@ieee.org
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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#include <stdlib.h>
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#include <ctype.h>
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float atof(const char * s)
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{
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float value, fraction;
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char iexp;
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char sign;
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//Skip leading blanks
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while (isspace(*s)) s++;
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//Get the sign
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if (*s == '-')
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{
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sign=1;
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s++;
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}
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else
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{
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sign=0;
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if (*s == '+') s++;
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}
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//Get the integer part
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for (value=0.0f; isdigit(*s); s++)
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{
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value=10.0f*value+(*s-'0');
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}
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//Get the fraction
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if (*s == '.')
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{
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s++;
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for (fraction=0.1f; isdigit(*s); s++)
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{
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value+=(*s-'0')*fraction;
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fraction*=0.1f;
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}
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}
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//Finally, the exponent (not very efficient, but enough for now)
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if (toupper(*s)=='E')
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{
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s++;
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iexp=(char)atoi(s);
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{
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while(iexp!=0)
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{
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if(iexp<0)
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{
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value*=0.1f;
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iexp++;
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}
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else
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{
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value*=10.0f;
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iexp--;
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}
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}
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}
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}
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if(sign) value*=-1.0f;
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return (value);
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}
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