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#include <math.h>
#include <stdio.h>
/*Mini program för att få gå och lägga sig =(*/
void
main (void)
{
float i, a;

i=10;
a=-10;
atan2(i, a);
}

Kod: Markera allt

Clean: Deleting intermediary and output files.
Clean: Done.
Build C:\pic\test\test for device 18F4550
Using driver C:\Program Files (x86)\HI-TECH Software\PICC-18\9.80\bin\picc18.exe

Executing: "C:\Program Files (x86)\HI-TECH Software\PICC-18\9.80\bin\picc18.exe" --pass1 C:\pic\test\temp.c -q --chip=18F4550 -P --runtime=default,+clear,+init,-keep,-download,+stackwarn,-config,+clib,+plib --opt=default,+asm,-debug,-speed,+space,9 --warn=0 -D__DEBUG=1 --rom=default --ram=default -Blarge --double=24 --float=24 --cp=16 --addrqual=ignore -g --asmlist "--errformat=Error   [%n] %f; %l.%c %s" "--msgformat=Advisory[%n] %s" "--warnformat=Warning [%n] %f; %l.%c %s" 
Executing: "C:\Program Files (x86)\HI-TECH Software\PICC-18\9.80\bin\picc18.exe" -otest.cof -mtest.map --summary=default,-psect,-class,+mem,-hex --output=default,-inhx032 temp.p1 --chip=18F4550 -P --runtime=default,+clear,+init,-keep,-download,+stackwarn,-config,+clib,+plib --opt=default,+asm,-debug,-speed,+space,9 --warn=0 -D__DEBUG=1 --rom=default --ram=default -Blarge --double=24 --float=24 --cp=16 --addrqual=ignore -g --asmlist "--errformat=Error   [%n] %f; %l.%c %s" "--msgformat=Advisory[%n] %s" "--warnformat=Warning [%n] %f; %l.%c %s" 
Licensed for evaluation purposes only.
This licence will expire on Thu, 24 Nov 2011.
HI-TECH C Compiler for PIC18 MCUs (PRO Mode)  V9.80
Copyright (C) 2011 Microchip Technology Inc.
Advisory[1233] Employing 18F4550 errata work-arounds:
Advisory[1234]  * Corrupted fast interrupt shadow registers
Error   [1089] C:\Program Files (x86)\HI-TECH Software\PICC-18\9.80\sources\ftmul.c; 52. recursive function call to "___ftmul"
Error   [1089] C:\Program Files (x86)\HI-TECH Software\PICC-18\9.80\sources\float.c; 63. recursive function call to "___ftpack"
Error   [1089] C:\Program Files (x86)\HI-TECH Software\PICC-18\9.80\sources\ftneg.c; 16. recursive function call to "___ftneg"
Error   [1089] C:\Program Files (x86)\HI-TECH Software\PICC-18\9.80\sources\wmul.c; 3. recursive function call to "___wmul"

********** Build failed! **********

Kod: Markera allt

This does indeed seem to be a compiler problem, but it looks like it might only affect this function.

There could be a reentrancy issue here. A function is considered "called" as soon as its parameter area has started to be loaded. If a function, which has to be called to obtain the parameter for another call, clobbers any parameters already loaded for the other call, then data corruption has occurred, which is what the compiler is trying to detect. When an expression involves multiple calls (and remember that most floating point math operations like +, * and / become calls) then this situation can occur quite frequently. It is possible the atan2 code could be tweaked so that this is avoided. However, I tried copying the atan2.c source file (provided) into my test project and it then built okay. I am not sure why that is that case, but this might be a work-around for you.

I'll log a fault. 

Kod: Markera allt

#include	<math.h>
#include	<errno.h>

#define PI	3.14159265358979
#define HALF_PI	1.57079632679489

double
atan2(double y,double  x)
{
	double	v;

	if (x == 0) {
		if (y == 0) {
			errno = EDOM;
			return 0;
		}
		if (y > 0) {
			  return HALF_PI;
		}
		else {
			  return -HALF_PI;
		}
	}
	if (y == 0) {
		if (x > 0) {
			  return 0;
		}
		else {
			  return PI;
		}
	}
	if(fabs(x) >= fabs(y)) {
		v = atan(y/x);
		if( x < 0.0)
			if(y >= 0.0)
				v += PI;
			else
				v -= PI;
		return v;
	}
	v = -atan(x/y);
	if(y < 0.)
		v -= HALF_PI;
	else
		v += HALF_PI;
	return v;
}