| ??? 07/07/08 14:49 Read: times |
#156480 - A common side effect of optimisation Responding to: ???'s previous message |
One thing I got tripped up on many years ago and I've seen many references to it is shared variables between interrupt code and main code. Without these variables declared as 'volatile' the compiler may decide to keep copies of the variable in registers as part of it's optimisation strategy. Turn off the optimisation and the code works, turn it on and it dies. Declare the shared variables as 'volatile', turn optimisation on and it works again. Also, things like delay loops can get optimised out as the compiler figures out the variable is not used elsewhere. Again, coreect declaration of the variable tells the compiler what you want. |
| Topic | Author | Date |
| Why Is Debugging Optimized Code Such an Issue? | 01/01/70 00:00 | |
| Usually not | 01/01/70 00:00 | |
| False Assumptions | 01/01/70 00:00 | |
| "language specification" ?? | 01/01/70 00:00 | |
| Do not assume it is that easy | 01/01/70 00:00 | |
| Common Stuff Leading To Errors | 01/01/70 00:00 | |
| "common stuff" falling apart when optimized | 01/01/70 00:00 | |
| How broken things work | 01/01/70 00:00 | |
| It is not like that | 01/01/70 00:00 | |
| A bad workman blames his tools | 01/01/70 00:00 | |
| A common side effect of optimisation | 01/01/70 00:00 | |
| Newbies | 01/01/70 00:00 | |
| another good reason | 01/01/70 00:00 | |
| a rule of thumb | 01/01/70 00:00 | |
| excellent advice, however - and | 01/01/70 00:00 | |
| Defeatist? | 01/01/70 00:00 | |
| Or turn it down as needed | 01/01/70 00:00 | |
| Using Pragmas During Debugging | 01/01/70 00:00 | |
| Free lunch? | 01/01/70 00:00 | |
| a dream | 01/01/70 00:00 | |
| If it were easy everone would be doing it. | 01/01/70 00:00 | |
you can't | 01/01/70 00:00 |