| ??? 10/27/11 18:33 Read: times |
#184398 - Still failing to recognize reason for hole in code map Responding to: ???'s previous message |
Richard Erlacher said:
That's only true if the evaluation compiler puts the code where it can actually run on the target. That is, after all, the issue that initiated this discussion. Doesn't matter if I have to use a processor with more code space when evaluating the compiler. The goal of evaluation is to find out if the compiler is good. It will be good whatever 8051 chip you use, since they all use the same instruction set. An evaluation version that allows the code to be placed at any location would mean that a user only making use of chips with 4kB of code space never needs to buy any commercial version of the compiler. So it really is important for the compiler vendor to give them an incentive to switch from the evaluation version to a bought version. Richard said:
Nobody's discussing "ARM-class" processors at this point. I know ARM would like to supplant the 805x's but there are places where they'll NEVER fit. But you missed the important note here, that I gave in the next paragraph (quoted below): lots of embedded code is more or less one-to-one between source lines and peripherial accesses. So not much need for any optimization. We do not want the compiler to remove writes to our UART transmit registers or reads from GPIO pins. And the compiler may not change the order. Richard said:
But even more importantly - the critical part of code is likely to contain lots if GPIO accesses, where there is a one-to-one between source lines and hardware accesses. Exactly how can a compiler fail when there isn't anything to optimize? I'm not sure optimization is the issue. Compilers from different vendors produce code that runs at different rates, uses differing volumes of code space, uses more or fewer resources ... But that can be evaluated within 4kB of code space for an 8051 compiler. Richard said:
After being repeatedly lied-to by the KEIL people, not to suggest they're the only ones, and probably as much out of ignorance as out of evil intent, I've nearly given up on trying to deal with software vendors. Strong claim from you. Care to back up that with some examples of how Keil staff have lied to you? |
