topic Re: how to allocate and declare const string messages in CodeWarrior for MCU

how to allocate and declare const string messages

admin — Thu, 12 May 2011 14:38:22 GMT

i need help,

i'm working on a project using microcontroler freescale MC9S12DT512 S12X familly

i need to put into the PAGE FE a big table of messages.

so inside my project i declare my table like it :

#pragma CONST_SEG MYCONSTANTS

#define mess_1_FRANCAIS "HELLO WORLD"

#define mess_1_FRANCAIS "I NEED HELP"

#define mess_1_FRANCAIS "FOR MY PROGRAMM"

#define mess_1_FRANCAIS "THANK YOU"

char* __far const texte_menu_FRANCAIS[] = {

    mess_1_FRANCAIS,
    mess_2_FRANCAIS,
    mess_3_FRANCAIS,
    mess_4_FRANCAIS

}

#pragma CONST_SEG DEFAULT

So my constant table of messages was created and i put it inside a segment named MYCONSTANTS

then i allocate this segment into the PAGE FE,

to do it i modify the PRM file of my project lije it :

PLACEMENT /* here all predefined and user segments are placed into the SEGMENTS defined above. */
    _PRESTART,
    STARTUP,
    ROM_VAR,
    NON_BANKED,
    COPY                            INTO   ROM_C000;
    DEFAULT_ROM             INTO   PAGE_E0, PAGE_E1, PAGE_E2, PAGE_E3, PAGE_E4, PAGE_E5, PAGE_E6, PAGE_E7,
                                                         PAGE_E8, PAGE_E9, PAGE_EA, PAGE_EB, PAGE_EC, PAGE_ED, PAGE_EE, PAGE_EF,
                                                          PAGE_F0, PAGE_F1, PAGE_F2, PAGE_F3, PAGE_F4, PAGE_F5, PAGE_F6, PAGE_F7,
                                                         PAGE_F8, PAGE_F9, PAGE_FA, PAGE_FB, PAGE_FC ;
    DEFAULT_RAM              INTO   RAM;
    DEFAULT_EEPROM      INTO   EEPROM1, EEPROM2;

    MYCONSTANTS, STRINGS        INTO PAGE_FE;
END

now, after compilation i obtain this in the MAP FILE :

- VARIABLES:
     STRING..20                                           FE89E1       1       1            2   .rodata1
     STRING.NG120.FRANCAIS.21           FE89E2       F      15            2   .rodata1
     STRING.V2.19.22                               FE89F1       6       6             2   .rodata1
     STRING.NIVEAU.23                              FE89F7       7       7              2   .rodata1

texte_menu_FRANCAIS FE8010 88E 2190 2 MYCONSTANTS

so we can see the const messages was inside the PAGE FE.

now i run my project with a debugger and i scope the texte_menu_FRANCAIS :

but when i expand my table texte_menu_français i can see the adress of each message

message 1 located at 0x7F89E1

message 2 located at 0x7F89E2

message 3 located at 0x7F89F1

message 4 located at 0x7F89F7

SO LOOK the begining of the address is not correct i obtain 0x7F for all messages instead of 0xFE

normally i must have oxFE because my map file indicate that messages are in the page FE.

SO i don't understand ????

to finish i have a function to access to messages with a classical pointer like it :

uint8 Find_String(uint8 lign, uint16 mes)
{
uint8 txt,curseur;

const char* __far ptr;

     ptr = texte_menu_FRANCAIS[mes];

     txt = 1;
while(txt)

{
txt = *ptr++;

}

so with my pointer i try to access to each letter of my messages but it doesn't work.

please could someone, an expert can help me i don't know what can i do now, i'm working on this proble since 3 days ..

fabrice

Re: how to allocate and declare const string messages

CrasyCat — Thu, 12 May 2011 16:49:19 GMT

Hello

The problem lies with definition of the table texte_menu_FRANCAIS. You need to inform the compiler that the table is allocated in a banked memory area.

You need to change your pragma as

#pragma CONST_SEG FAR MYCONSTANTS

address for texte_menu_FRANCAIS[0] shown 0x7F89E1, which is the global address encoding for logical address 0xFE89E1.

So your addresses are all correct.

CrasyCat

Re: how to allocate and declare const string messages

admin — Thu, 12 May 2011 17:12:57 GMT

it's WONDERFULL

MR CRAZYCAT you can't imagine the power of the help you just give me

i don't know how to tell you how i'm happy of your very necessary help

without you i probably don't find the solution

crazycat, receive my best thank's from a french programmer who lost a lot of hair with this problem.

crazy cat you are a god, guru of code.

fabrice

Re: how to allocate and declare const string messages

kef — Thu, 12 May 2011 17:17:30 GMT

fab48,

MC9S12DT512 is not from S12X family, though your PRM looks like you are working with MC9S12XDT512, not with MC9S12DT512.

You should not place default STRINGS into banked segment (PAGE_FE), unless you are using large memory model. Else other non far strings won't be accessible properly.

char* __far const texte_menu_FRANCAIS[] is an array of const far pointers to non-far strings. Array of pointers is usually small and could be non-far for better size and speed performance. I guess you need either far or non-far array of pointers to far strings:

const char __far * __far const texte_menu_FRANCAIS[];

But the problem is how to initialize this array with far strings. I don't know how to tell compiler to allocate "HELLO WORLD" initializer in non default STRINGS segment. You could replace defines with far strings

#pragma CONST_SEG __FAR_SEG MYCONSTANTS

const __far char mess_1_FRANCAIS[] "HELLO WORLD"; // now string should be allocated in MECONSTANTS

If you have up to 16k of strings, then why don't you allocate them in nonbanked segment 4000-7fff ? It would be much faster to access such strings.

Re: how to allocate and declare const string messages

admin — Thu, 12 May 2011 20:16:57 GMT

it's a mistake my processor is a X? LIKE S12X

currently i try to migrate my project from

MC9S12XDG128

MC9S12XDT512

now i have more memory i can put all languages in the same software.

JUST A QUESTION :

when i add the modifier FAR to my segment (see my first post) like crazycat said me :

#pragma CONST_SEG FAR MYCONSTANTS

the software work but the compiler cry me a warning :

Warning : C3803: Illegal segment attribute FAR supported for CODE segments only. Use DPAGE/EPAGE/GPAGE/RPAGE/PPAGE for DATA/CONST/STRING
segments

the memory model of my project is banked;

what i must do ?

I HAVE READ THE DOCUMENT ABOUT IT on freescale knowledge base but it's not very clear for me

if someone can tell me what to do witha little explanation

thank

fabrice

Re: how to allocate and declare const string messages

kef — Thu, 12 May 2011 21:06:31 GMT

#pragma CONST_SEG __GPAGE_SEG MYCONSTANTS

You should restore placement of defaultt near strings to ROM_C000 or to ROM_4000.

STRINGS INTO ROM_C000;

MYCONSTANTS INTO PAGE_FE;

Then:

#pragma CONST_SEG __GPAGE_SEG MYCONSTANTS

static const char __far mess_1_FRANCAIS[]=   "HELLO WORLD";
static const char __far mess_2_FRANCAIS[]=   "I NEED HELP";
static const char __far mess_3_FRANCAIS[]=   "FOR MY PROGRAMM";
static const char __far mess_4_FRANCAIS[]=   "THANK YOU";

const char __far * const __far texte_menu_FRANCAIS[] = {
    mess_1_FRANCAIS,
    mess_2_FRANCAIS,
    mess_3_FRANCAIS,
    mess_4_FRANCAIS
};

#pragma CONST_SEG DEFAULT

To optimize access times you can move quite small texte_menu_FRANCAIS to nonbanked ROM, kepping tons of strings in MYCONSTANTS segment:

#pragma CONST_SEG __GPAGE_SEG MYCONSTANTS

#pragma CONST_SEG DEFAULT

const char * const __far texte_menu_FRANCAIS[] = { // strings in MYCONSTSEG,

                                                                                        // but texte_menu_FRANCAIS in near seg
    mess_1_FRANCAIS,
    mess_2_FRANCAIS,
    mess_3_FRANCAIS,
    mess_4_FRANCAIS
};

Or even better allocate MYCONSTSEG in ROM_4000 and use fast and small nonbanked data accesses.

Re: how to allocate and declare const string messages

kef — Fri, 13 May 2011 12:47:32 GMT

Please disregard suggestion to give each far string the name. I forgot about STRING_SEG.

#pragma CONST_SEG __GPAGE_SEG MYCONSTANTS

#pragma STRING_SEG __GPAGE_SEG MYCONSTANTS

#define mess_1_FRANCAIS   "HELLO WORLD"
#define mess_2_FRANCAIS   "I NEED HELP"
#define mess_3_FRANCAIS   "FOR MY PROGRAMM"
#define mess_4_FRANCAIS   "THANK YOU"

const char __far * const __far texte_menu_FRANCAIS[] = {
    mess_1_FRANCAIS,
    mess_2_FRANCAIS,
    mess_3_FRANCAIS,
    mess_4_FRANCAIS
};

#pragma STRING_SEG DEFAULT

#pragma CONST_SEG DEFAULT

Re: how to allocate and declare const string messages

admin — Sat, 14 May 2011 12:51:48 GMT

Kef,

thank you for your help and the time you spend to help me.

can i ask you an other thing :

you seems to know very well all this near far gpage an relocatable problems,

i came from MICROCHIP world my society decide to work with frescale micro, as i said it's von-neuman architecture to compare with harvard of microchip, it's the reason why i'm so embarassed.

did you know where i can find a very good description with all keyword of this, like an application note for example or a tuturial or some other document well explained because the datasheet i have are difficult to understand.

perhaps you have a link for example ?

for me asking help for you is a good solution because what you said is right and works on my proket but i can't ask you each time i would like to know by mysefls if i can so if you know whre i can have information about all this banked unbanked, memrory model, far near etccc.

it will be better and necessary for me to study this.

once more KEF i don't know who you are and where you come from (probaly AMERICA) but receive my best thnk's for the help and the time you give me.

fabrice (from FRANCE)

Re: how to allocate and declare const string messages

kef — Sat, 14 May 2011 19:47:32 GMT

I don't know book to recommend.

CPU12X reference manual is important reading. You should read at least everything about available addressing modes (Chapter 3). Further, Appendix A Instruction Reference or Chapter 5 Instruction Glossary may tell you which addressing takes less code space and which takes less CPU cycless (see Access Deails - more letters means more CPU cycles).

http://cache.freescale.com/files/microcontrollers/doc/ref_manual/S12XCPUV2.pdf

You need of course to understand memory map of particular MCU.

The rest can be found in CW online help or in <CW install folder>\Help\PDF (which are more recent then CW help) and in <CW install folder>\Release Notes.