Read: 668 times
|#163420 - Can you have a look at this?|
Responding to: ???'s previous message
Thanks for all your comments. I agree that finding another consultant or even buying Keil might well have been cheaper and quicker overall, but I just had to find out what was wrong. I expect everyone here knows that feeling! In terms of validation, of course we have a test protocol that we wrote when the original software was commissioned, and we'd follow that any time there was a change, however trivial.
On to more technical matters, I think I have found the problem. Does the following look odd to you?
Here's the source; it's setting a register in extended memory. At MCU reset, the register is zero so it should end up with 0x0c in that register.
#define bMODECNFG (* (unsigned char xdata *)0xFFFB) #define MODECNFG_CLKOUTEN 0x04 #define MODECNFG_CLKSLCT 0x08 ... bMODECNFG |= MODECNFG_CLKOUTEN; bMODECNFG |= MODECNFG_CLKSLCT; ...
(ignore the fact it's not the most concise way to do this!)
Code generated by SDCC:
444 ; bMODECNFG |= MODECNFG_CLKOUTEN; 004B 7A FB 445 mov r2,#0xFB 004D 7B FF 446 mov r3,#0xFF 004F 90 FF FB 447 mov dptr,#0xFFFB 0052 E0 448 movx a,@dptr 0053 FC 449 mov r4,a 0054 74 04 450 mov a,#0x04 0056 4C 451 orl a,r4 0057 8A 82 452 mov dpl,r2 0059 8B 83 453 mov dph,r3 005B F0 454 movx @dptr,a 455 ; bMODECNFG |= MODECNFG_CLKSLCT; 005C 90 FF FB 456 mov dptr,#0xFFFB 005F 43 04 08 457 orl ar4,#0x08 0062 EC 458 mov a,r4 0063 F0 459 movx @dptr,a
This (as far as I can see) results in 0x04 in the register.
Equivalent dissassembled from the Keil version:
X10be: mov dptr,#Xfffb movx a,@dptr orl a,#4 movx @dptr,a movx a,@dptr orl a,#8 movx @dptr,a
This looks a lot more sensible (and shorter!)
I changed the source to
bMODECNFG |= (MODECNFG_CLKOUTEN|MODECNFG_CLKSLCT);
and it now works perfectly on SDCC.
Do you agree this is a bug in SDCC's code generation?
|SDCC and Keil and I/O||James Best||03/10/09 06:29|
|No big changes for SDCC||David Prentice||03/10/09 08:51|
|Nothing obvious||Oliver Sedlacek||03/10/09 09:09|
|just curious||Erik Malund||03/10/09 09:41|
|Just what do you mean, Erik?||Richard Erlacher||03/10/09 10:22|
|even the SDCC 'friends' agree||Erik Malund||03/10/09 10:31|
|Answers to your quiz||David Prentice||03/10/09 10:39|
|5th||Jan Waclawek||03/10/09 11:27|
|But the really difficult question is...||Andy Neil||03/11/09 01:47|
|Thanks! and a bit of background||James Best||03/11/09 04:17|
|Am I going crazy?||James Best||03/11/09 07:32|
|Is the code large then 2K?||Chris Bertrand||03/11/09 09:52|
|Keil deserves a medal if it is using USB in less than 2kB||David Prentice||03/11/09 10:42|
|Keil probably has nothing to do with the USB?||Andy Neil||03/11/09 10:59|
|If only it where that simple||Neil Kurzman||03/11/09 21:57|
|TUSB3410||Andy Peters||03/12/09 12:01|
|Test costs?||Oliver Sedlacek||03/12/09 01:59|
|Initially maintain a compatible source||David Prentice||03/11/09 03:49|
|But||Neil Kurzman||03/12/09 22:42|
|Can you have a look at this?||James Best||03/13/09 07:13|
|use "__xdata volatile unsigned char __at(0xfffb) bMODECNF"||Frieder Ferlemann||03/13/09 08:04|
|Done!||James Best||03/13/09 08:32|
|thanks||Frieder Ferlemann||03/13/09 09:09|
|register bank, ar4?||Juergen Christoph||03/13/09 08:13|
|A free 3-month full Keil PK51 licence||Andy Neil||03/20/09 07:45|
|Thanks for the link!||James Best||03/25/09 03:27|