I'm doing a state machine to receive commands from the UASRT and this one case (code below) isn't working. Inspecting the lss output, it seems that GCC is optimizing out the buffer[Counter] = uart_tmp (check the output list after the code).
If I make buffer a global variable, GCC generates correct code. It doesn't need to be global, as it is only used inside the State_Machine function.
Any clues as why it is behaving like this?
Btw, I'm using WinAVR20100110 (dowloaded after 20/01/2010) and a m168 @ 18.432MHz.
void State_Machine (void)
{
uint8_t uart_tmp;
char buffer[33]; // 32 bytes + \0
...
case SM_VFD_STR:
uart_tmp = uart_getc();
if (uart_tmp != 0x0D) // 0x0D = Enter
{
buffer[Counter] = uart_tmp;
Counter++;
if (Counter > 32)
{
CurState = SM_ERROR;
TipoErro = VFD_ERROR_STR;
}
}
else
{
buffer[Counter] = 0;
uart_puts(buffer);
vfd_setstring(buffer);
CurState = SM_END;
}
break;
...
case SM_VFD_STR:
uart_tmp = uart_getc();
8f2: 9e dc rcall .-1732 ; 0x230
8f4: 90 91 5e 01 lds r25, 0x015E
if (uart_tmp != 0x0D) // 0x0D = Enter
8f8: 8d 30 cpi r24, 0x0D ; 13
8fa: 69 f0 breq .+26 ; 0x916 <__stack+0x417>
{
buffer[Counter] = uart_tmp; // <-- it's not generating code!
Counter++;
8fc: 89 2f mov r24, r25
8fe: 8f 5f subi r24, 0xFF ; 255
900: 80 93 5e 01 sts 0x015E, r24
if (Counter > 32)
904: 81 32 cpi r24, 0x21 ; 33
906: 20 f1 brcs .+72 ; 0x950 <__stack+0x451>
{
CurState = SM_ERROR;
908: 80 e1 ldi r24, 0x10 ; 16
90a: 80 93 40 01 sts 0x0140, r24
TipoErro = VFD_ERROR_STR;
90e: 89 e0 ldi r24, 0x09 ; 9
910: 80 93 5f 01 sts 0x015F, r24
914: 1d c0 rjmp .+58 ; 0x950 <__stack+0x451>
}
}
