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/*
nuts_bolts.c - Shared functions
Part of Grbl v0.9
Copyright (c) 2012-2014 Sungeun K. Jeon
Grbl is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Grbl is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Grbl. If not, see <http://www.gnu.org/licenses/>.
*/
/*
This file is based on work from Grbl v0.8, distributed under the
terms of the MIT-license. See COPYING for more details.
Copyright (c) 2009-2011 Simen Svale Skogsrud
Copyright (c) 2011-2012 Sungeun K. Jeon
*/
#include "system.h"
#include "print.h"
#define MAX_INT_DIGITS 8 // Maximum number of digits in int32 (and float)
// Extracts a floating point value from a string. The following code is based loosely on
// the avr-libc strtod() function by Michael Stumpf and Dmitry Xmelkov and many freely
// available conversion method examples, but has been highly optimized for Grbl. For known
// CNC applications, the typical decimal value is expected to be in the range of E0 to E-4.
// Scientific notation is officially not supported by g-code, and the 'E' character may
// be a g-code word on some CNC systems. So, 'E' notation will not be recognized.
// NOTE: Thanks to Radu-Eosif Mihailescu for identifying the issues with using strtod().
uint8_t read_float(char *line, uint8_t *char_counter, float *float_ptr)
{
char *ptr = line + *char_counter;
unsigned char c;
// Grab first character and increment pointer. No spaces assumed in line.
c = *ptr++;
// Capture initial positive/minus character
bool isnegative = false;
if (c == '-') {
isnegative = true;
c = *ptr++;
} else if (c == '+') {
c = *ptr++;
}
// Extract number into fast integer. Track decimal in terms of exponent value.
uint32_t intval = 0;
int8_t exp = 0;
uint8_t ndigit = 0;
bool isdecimal = false;
while(1) {
c -= '0';
if (c <= 9) {
ndigit++;
if (ndigit <= MAX_INT_DIGITS) {
if (isdecimal) { exp--; }
intval = (((intval << 2) + intval) << 1) + c; // intval*10 + c
} else {
if (!(isdecimal)) { exp++; } // Drop overflow digits
}
} else if (c == (('.'-'0') & 0xff) && !(isdecimal)) {
isdecimal = true;
} else {
break;
}
c = *ptr++;
}
// Return if no digits have been read.
if (!ndigit) { return(false); };
// Convert integer into floating point.
float fval;
fval = (float)intval;
// Apply decimal. Should perform no more than two floating point multiplications for the
// expected range of E0 to E-4.
if (fval != 0) {
while (exp <= -2) {
fval *= 0.01;
exp += 2;
}
if (exp < 0) {
fval *= 0.1;
} else if (exp > 0) {
do {
fval *= 10.0;
} while (--exp > 0);
}
}
// Assign floating point value with correct sign.
if (isnegative) {
*float_ptr = -fval;
} else {
*float_ptr = fval;
}
*char_counter = ptr - line - 1; // Set char_counter to next statement
return(true);
}
// Delays variable defined milliseconds. Compiler compatibility fix for _delay_ms(),
// which only accepts constants in future compiler releases.
void delay_ms(uint16_t ms)
{
while ( ms-- ) { _delay_ms(1); }
}
// Delays variable defined microseconds. Compiler compatibility fix for _delay_us(),
// which only accepts constants in future compiler releases. Written to perform more
// efficiently with larger delays, as the counter adds parasitic time in each iteration.
void delay_us(uint32_t us)
{
while (us) {
if (us < 10) {
_delay_us(1);
us--;
} else if (us < 100) {
_delay_us(10);
us -= 10;
} else if (us < 1000) {
_delay_us(100);
us -= 100;
} else {
_delay_ms(1);
us -= 1000;
}
}
}
// Simple hypotenuse computation function.
float hypot_f(float x, float y) { return(sqrt(x*x + y*y)); }
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