Anthony,
Are you linking the file that contains main() as the
first object? It looks like the linker has put
sdcc_call_dptr() at the address of the reset vector
which makes it jump to whatever A+DPTR is after reset.
Maarten
> another strange observation. If I move the actual declaration of the
> sensors_event to a different file everything works. Unfortunately this
> is not a suitable long term solution.
>
> Anthony Asterisk wrote:
> > I hit a very frustrating problem yesterday and a solution is still
> > alluding me. Unfortunately the problem shows up when trying to
> > execute the linked ihx file on the target platform so it is not easy
> > for me to provide a testcase. I will give some code snippets, please
> > let me know any steps I can take to further debug it.
> >
> >
> > Here is the code that I am altering. A working version looks like this:
> >
> > printf("\n\npress button ");
> > etimer_set(&timer,CLOCK_CONF_SECOND/5);
> > while (1) {
> > PROCESS_WAIT_EVENT();
> > if (ev==PROCESS_EVENT_TIMER) {
> > etimer_reset(&timer);
> > lcd_putchar(0x08);
> > lcd_putchar(spin[spin_ptr]);
> > spin_ptr = (spin_ptr+1)%4;
> > }
> > else if (ev==PROCESS_EVENT_MSG) {
> > //else if (ev == sensors_event) {
> > exp_port.fields.leds++;
> > }
> > else {
> > printf("unknown event\n");
> > }
> > }
> >
> > With this code the message "press button" is displayed.
> >
> > If I switch the commented lines ONLY, press button is never displayed
> > and it seems like nothing is even loaded/executed on the target platform.
> >
> > printf("\n\npress button ");
> > etimer_set(&timer,CLOCK_CONF_SECOND/5);
> > while (1) {
> > PROCESS_WAIT_EVENT();
> > if (ev==PROCESS_EVENT_TIMER) {
> > etimer_reset(&timer);
> > lcd_putchar(0x08);
> > lcd_putchar(spin[spin_ptr]);
> > spin_ptr = (spin_ptr+1)%4;
> > }
> > //else if (ev==PROCESS_EVENT_MSG) {
> > else if (ev == sensors_event) {
> > exp_port.fields.leds++;
> > }
> > else {
> > printf("unknown event\n");
> > }
> > }
> >
> >
> > The extern declaration of sensors_event is in an included header
> > file. It looks like this:
> >
> > extern process_event_t sensors_event;
> >
> > And the actual declaration (in a code file) looks like this:
> >
> > process_event_t sensors_event;
> >
> >
> > Nothing surprising there.
> >
> >
> > I've been digging around in the *.sym and linker output *.map file for
> > some clue.
> >
> > In the *.sym file for the module with the code snippet above I see:
> >
> > _sensors_event
> > **** GX
> >
> >
> > In the aslink output *.map file, I see:
> >
> > Hexadecimal
> >
> > Area Addr Size Decimal Bytes
> > (Attributes)
> > -------------------------------- ---- ---- ------- -----
> > ------------
> > XSEG E000 0291 = 657. bytes
> > (REL,CON,XDATA)
> >
> > Value Global
> > -------- --------------------------------
> > 0D:E010 _exp_port
> > 0D:E016 _ddram_addr
> > 0D:E017 _sensors_event
> > 0D:E10D _p0ien
> > 0D:E10E _p2ien
> >
> >
> > If I diff the *.map from the working and non-working version, the
> > results are very similar. The order of several various changes but
> > they are all still present. One change that I did notice which has me
> > wondering:
> >
> >
> > 431,432c431,432
> > < 0C:0000 __sdcc_call_dptr
> > < 0C:0088 __sdcc_program_startup
> > ---
> > > 0C:0086 __sdcc_program_startup
> > > 0C:008B __sdcc_call_dptr
> >
> >
> > these differences are here:
> >
> > Area Addr Size Decimal Bytes
> > (Attributes)
> > -------------------------------- ---- ---- ------- -----
> > ------------
> > HOME 0000 008D = 141. bytes
> > (REL,CON,CODE)
> >
> > Value Global
> > -------- --------------------------------
> > 0C:0000 __sdcc_call_dptr
> > 0C:0088 __sdcc_program_startup
> >
> > Hexadecimal
> >
> >
> >
> >
> > The working version seems to have a non-null address for the
> > __sdcc_call_dptr code, but the broken version has NULL. 0000 seems to
> > me like it might indicate some sort of error.
>
>
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