| ??? 06/09/11 10:21 Read: times |
#182549 - Exactly what you wrote Responding to: ???'s previous message |
Sandy B. Pal said:
if(up_pressed) // is up key pressed?
goto up1;
if(dn_pressed) // is down key pressed?
goto dn1;
}
dn1: if (dn_pressed)
First, please don't use TABs when pasting code and be sure to use the Preview before posting. Now look at the code: both when the first if(dn_pressed) is either true or false, the next statement is at label dn1:. So there is no need to evaluate the if statement. But since dn_pressed is an sbit it is inherently volatile and thus must be read when the code says so. That's why its value is sampled into the carry flag. The next statement is again if (dn_pressed) and is implemented with the jnb instruction. |
| Topic | Author | Date |
| Compiler variations?? | 01/01/70 00:00 | |
| Fundamental philosophy of High-Level Languges (HLL) | 01/01/70 00:00 | |
| C code | 01/01/70 00:00 | |
| and so what | 01/01/70 00:00 | |
| Stop wondering about the compiler output | 01/01/70 00:00 | |
| Very nice to learn this important matter | 01/01/70 00:00 | |
| Exactly what you wrote | 01/01/70 00:00 | |
| volatile sbit may be the problem | 01/01/70 00:00 | |
| read up on (not) volatile | 01/01/70 00:00 | |
| Look at my profile | 01/01/70 00:00 | |
| Not offence intended | 01/01/70 00:00 | |
| defining P0_6 so that compiler doesn't treat it as volatile | 01/01/70 00:00 | |
| Skip the goto - almost always exists beautiful rewrites | 01/01/70 00:00 | |
| Goto really is a bastard code construct | 01/01/70 00:00 | |
| and therefore ... | 01/01/70 00:00 | |
Will come back with modified code | 01/01/70 00:00 | |
| Wonderful as always! | 01/01/70 00:00 |