[sdcc-devel] [ sdcc-Bugs-1358533 ] Global variables do not work as loop operands

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Bugs item #1358533, was opened at 2005-11-17 00:02
Message generated for change (Comment added) made by vvillatora
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Category: z80 port
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Steven J Tucker (atarimax)
Assigned to: Nobody/Anonymous (nobody)
Summary: Global variables do not work as loop operands

Initial Comment:

unsigned char x;
unsigned char y;

void do_domething_else( unsigned char row )
{
   // whatever...  will be called once with row = 0 but
not again.
}

void do_something( void )
{
   unsigned char _tmp;

   for (_tmp = x; _tmp < y; _tmp++)
   {
      // being called only once, not y times!
      do_something_else(_tmp);
   }

void main( void )
{
   x = 0;
   y = 23;

   do_something();
}

Declaring x or y extern in functions does not help.  No
warnings or errors are produced, the code generated
just doesnt work properly.

Doing the following will force it to work:

Change:

   for (_tmp = x; _tmp < y; _tmp++)
 
To:

   for (_tmp = x; _tmp < 23; _tmp++)

or doing

y=23

just before the for statement

neither are work arounds to making a working program
that uses global variables.

SDCC :
mcs51/gbz80/z80/avr/ds390/pic16/pic14/TININative/xa51/ds400/hc08
2.5.0 #1020 (May  8 2005) (UNIX) 

email: cla...@at...


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Comment By: Virgilio Eng. Villatora (vvillatora)
Date: 2006-09-30 10:56

Message:
Logged In: YES 
user_id=1610032

It is very critical code if you use global variable for 
loops...

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

You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=100599&aid=1358533&group_id=599