[sdcc-devel] [ sdcc-Bugs-1383846 ] Variable initializers ignored

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Bugs item #1383846, was opened at 2005-12-17 19:47
Message generated for change (Comment added) made by tecodev
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Category: pic14 target
>Group: fixed
>Status: Closed
>Resolution: Fixed
Priority: 5
Private: No
Submitted By: Simon McAuliffe (smcauliffe)
Assigned to: Nobody/Anonymous (nobody)
Summary: Variable initializers ignored

Initial Comment:
Variables are not initialized to specified values in
some cases.  This occurs when multiple source files are
used (perhaps when there is no main() function in a
given file).

Sample code:
-------------bug6.c-------------
#define __16f627
#include <pic/pic16f627.h>

static char myotherval = 0xaa;  // Initialized
static char andanother;

extern char get();

void main()
{
  PORTB = get();
}
-------------bug6a.c-------------
#define __16f627
#include <pic/pic16f627.h>

static char myval = 0x55; // Not initialized

char get()
{
  return myval;
}
--------------------------------

Command used:
sdcc/bin/sdcc -c -mpic14 -p16f627 bug6.c &&
sdcc/bin/sdcc -c -mpic14 -p16f627 bug6a.c && gplink -m
-c -o bug.hex bug6.o bug6a.o

Version: 2.5.4 #1183

Symptoms:
The application will not output the correct value 0x55
to PORTB in this case.


Another possible (though very minor) problem:
If I recall correctly, while automatic variables are
not supposed to be implicitly initialized, I think
static and extern variables are supposed to be
initialized to 0 if no value is explicitly given.  This
suggests the variable "andanother" in the code above
should also be initialized to 0, which it isn't.


BTW, this is not the static bug I previously mentioned.
I'm still looking for that again :)


----------------------------------------------------------------------

>Comment By: Raphael Neider (tecodev)
Date: 2007-01-22 01:48

Message:
Logged In: YES 
user_id=1115835
Originator: NO

Fixed mostly in SDCC 2.6.4, r4592.

Variables in other modules than the one containing the main() function are
now properly initialized iff one links against __sdcc_gsinit_startup from
libsdcc.lib (default behaviour).
This adds 12 bytes of RAM usage, so for those not requiring initialized
data it is recommended to provide a substitute as follows:

void _sdcc_gsinit_startup(void) {
    __asm goto _main __endasm;
}

This will provide nearly the same functionality as before.

Concering uninitialized static variables; I have no idea whether the
compiler should do it or not. Closing this report despite this unresolved
issue.

Regards,
Raphael


----------------------------------------------------------------------

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