Hello,
I'm trying to display a menu on my device, with str710 mcu. To do that, I create use structs to hold the variables and display them later. My structs look like this:
typedef const struct mMenu_s { int type; char text[3][20]; struct command { int command; int argument; } commands; struct specialline { int een; int twee; int drie; } speciallines; } menutype; typedef struct sMenuTemp { menutype *mCurmenu[20]; int iCurmenu; int iCurmenupos; int iOldmenu; int iOldmenupos; int menuactive; } cmdMenu; extern cmdMenu sMenu;
And to place data in it I use:
cmdMenu sMenu; menutype Backlightmenu[] = { { 1, {"Rood", "Red", "Rot"}, {SET_BACKLIGHT,RED}, {NULL,NULL,NULL} }, { 2, {"Groen", "Green", "Grun"}, {SET_BACKLIGHT,GREEN}, {NULL,NULL,NULL} }, { 3, {"Wit", "White", "Weiss"}, {SET_BACKLIGHT,WHITE}, {NULL,NULL,NULL} }, { NULL } }; sMenu->mCurmenu[BACKLIGHTMENU] = Backlightmenu;
With this method I can let (other) programmers create/delete/edit a menu very easy. So far so good.. All the text, commands, arguments and the rest of variables are stored in the memory OK (checked the memory watch, all OK!). But then.. I wan't to display the texts. Selecting the menu, the menuline, the language and the text is no problem. But, with the displaying, the last line of my struct is getting destroyed.
I've debugged my program, and it seems that the LCD-library caused the problem. It does an integer division, and the assembly calls "__aeabi_idivmod", which is an divide-function. On the first instruction, which is: PUSH {R4-R6,LR}, the data of my struct get destroyed, and it very, very weird values on the place of the struct..
And, the stupid thing.. When I remove the graphic-function, it's all normal. And, it doesn't matter on what memory-location my struct is placed, it happens every time.. It looks like the divide haunts my struct =S.
I'm working with the MDK-Arm 3.70 toolchain, in uVision3. Does anybody have an idea why this happens? Or, even better, the solution? I've tried a lot of other things, but it would be so d*mn easy to build and display my menu like that...
Thank you so very much.
Jay.
Hi!
Thnx for your fast reply..
First; the data in the struct does not have to be modifiable.. It could be handy (to show a setting-from-flash in the menu for example) but it's not necessary. I've found something about the ROM-thing. Something with a "const"-definition. I tried, still same effect (on the divide-instruction).
I've already tripple-checked my pointers.. They look OK. When I search the memory-window with the adresses the variable-watch says, it shows me the data as it should be. But, when I keep an eye on the memory-watch, and I step trough the program (in the disassembler), the PUSH-instruction, with the registers I mentioned (the registers DOES hold data, but not from my struct) does mess up my struct..
But I don't get it.. I've tried to modify my struct and my code in many ways.. And whatever I tried, on what address my struct is stored.. It always get messed up by the PUSH-instruction.....
Maby I can try the ROM-thing again? Did I missed something? Do you have other suggestions? Thank you for your time!!