Dear sdcc community,
I am encountering a problem that is somehow connected to the cast
between float and int, and it is unclear to me whether I am using sdcc wrong or
whether there might be a bug somewhere. Please find below two pieces of code,
the first one works as expected, the value of debug is 6116. The second does
not work, I expect the value to be 6116, but I see a different number. It is
not clear to me whether this is always the same number and what influences its
value.
I compile for a PIC16F1938, using sdcc from svn (rev8435), configured with
--enable-new-pics (since pic16f1938 uses the "enhanced core") against gputils
r932.
$ sdcc -v
SDCC :
mcs51/gbz80/z80/z180/r2k/r3ka/ds390/pic16/pic14/TININative/ds400/hc08/s08 3.2.1
#8435 (Feb 17 2013) (Linux)
I compile using
$ sdcc -I/usr/local/share/sdcc/non-free/include/
-L/usr/local/share/^Ccc/non-free/lib/pic14/ -L/usr/local/share/^Ccc/lib/pic14
-mpic14 -p16f1938 problem.c
When comparing the asm outputs I see that the first example does not call
___fs2uint, why does it not need to do this to cast the value of x? What else
can I
do to narrow the problem down? Is there a debugger in which I can run these
programs on my computer and inspect the values after each step? Currently I use
a board with connected LED displays to inspect the value of debug (program
attached).
Thank you for any help.
//Daniel
$ cat problem_works.c
#define __16f1938
#include <float.h>
#include "pic14/pic16f1938.h"
static __code int __at(_CONFIG1) __CONFIG1 = _WDTE_OFF;
unsigned int debug = 1234;
void main(void) {
float x = 6116.0;
debug = x;
//debug is 6116.
}
$ cat problem.c
#define __16f1938
#include <float.h>
#include "pic14/pic16f1938.h"
/* Setup chip configuration */
static __code int __at(_CONFIG1) __CONFIG1 = _WDTE_OFF;
unsigned int debug = 1234;
float julianday = 6116.0;
void main(void) {
float x = 6116.0;
debug = julianday;
// expect 6116, obtain a vastly different (arbitrary?) number
}
#define __16f1938
#include <float.h>
#include "pic14/pic16f1938.h"
#include "ledd.h"
#define FOSC 8000000L
#define delayus(x) { unsigned char us; us = (x)/(12000000/FOSC)|1; while(--us != 0)continue; }
void delayms(unsigned int ms) { unsigned char i;
do { i = 4;
do {
delayus(164);
} while(--i);
} while(--ms);
}
/* Setup chip configuration */
static __code int __at(_CONFIG1) __CONFIG1 = _WDTE_OFF;
//_CLKOUTEN_ON & _BOREN_OFF & _PWRTE_OFF & _MCLRE_OFF & _WDTE_OFF & _FOSC_INTOSC;//_HS_OSC;// & _INTRC_OSC_NOCLKOUT;
//_INTRC_OSC_NOCLKOUT & _PWRTE_OFF; // &_BOR_OFF & _IESO_OFF & _FCMEN_OFF; // _CP_OFF
int debug = 1234;
float julianday = 6116.0f;
void transmit (int n, char dot) {
char databyte;
n %= 10;
n += '0';
switch(n){
case '0': databyte = ZERO; break;
case '1': databyte = ONE; break;
case '2': databyte = TWO; break;
case '3': databyte = THREE; break;
case '4': databyte = FOUR; break;
case '5': databyte = FIVE; break;
case '6': databyte = SIX; break;
case '7': databyte = SEVEN; break;
case '8': databyte = EIGHT; break;
case '9': databyte = NINE; break;
case ' ': databyte = SPACE;break;
default: databyte = DASH; break;
}
if(dot) {
databyte |= 0b00001000;
}
SSPBUF = databyte;
}
void main(void) {
float x = 6116;
ANSELA=0x00;
ANSELB=0x00;
PORTA = 0x00;
PORTB = 0x00;
LATA = 0x00;
LATB = 0x00;
// SSP communication to the LED displays
BOEN = 1;
SSPCON1 = 0b00110000; //Configures SSP for serial communication (SPI master mode, clock = FOSC/4)
TRISA = 0x00;
TRISB = 0b11011000; //RB4 & RB5 are digital inputs
WPUB = 0b11011000;
TRISC = 0x00;
debug = julianday; // some large number, unexpected
//debug = x; // 6116 as expected
while(1) {
LATC2 = 0;
transmit(debug, 1);
transmit(debug / 10, 1);
transmit(debug /100, 1);
transmit(debug /1000, 1);
LATC2 = 1;
delayms(10);
}
}
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