Lpc2000

Hi Guys,

I try to call the IAP-routines from ARM-mode with help of the code 
to enter THUMB-mode from the file section:

static void callIAP(void)
{
  // fast way to get the address of flashParams[] directly into r0
  register void *pFP asm("r0") = flashParams;

  asm volatile(" mov r1, r0\n"          // copy &flashParams[] into 
r1
               " bx  %[iapLocation]"    // 'bx' because IAP is Thumb 
mode
               :
               : "r" (pFP), [iapLocation] "r" (IAP_LOCATION)
               : "r1" );
}

The code runs fine, the IAP is entered in thumb mode and returns to 
ARM-mode again. Only nothing happens: when I try to read the Part Id 
(command 0x36) it returns 0. The same for the Boot Code (command 
0x37). R0 / R1 points to the (same) FlashParams. With help of the 
debugger I see the 0x36/0x37-commands in these parameters are 
overwritten by zero.

Who can help me please?

Thanks in advance,

Conrado

conrado wrote:

>Hi Guys,
>
>I try to call the IAP-routines from ARM-mode with help of the code 
>to enter THUMB-mode from the file section:
>
>static void callIAP(void)
>{
>  // fast way to get the address of flashParams[] directly into r0
>  register void *pFP asm("r0") = flashParams;
>
>  asm volatile(" mov r1, r0\n"          // copy &flashParams[] into 
>r1
>               " bx  %[iapLocation]"    // 'bx' because IAP is Thumb 
>mode
>               :
>               : "r" (pFP), [iapLocation] "r" (IAP_LOCATION)
>               : "r1" );
>}
>
>The code runs fine, the IAP is entered in thumb mode and returns to 
>ARM-mode again. Only nothing happens: when I try to read the Part Id 
>(command 0x36) it returns 0. The same for the Boot Code (command 
>0x37). R0 / R1 points to the (same) FlashParams. With help of the 
>debugger I see the 0x36/0x37-commands in these parameters are 
>overwritten by zero.
>
>  
>
I dunno, mine works and I didn't bother with ASM:

======== begin C call to ID ============

#define  IAP_LOCATION            0x7ffffff1

typedef void (*IAP)(unsigned int [],unsigned int[]);
unsigned int command_iap[5], result_iap[3];
IAP   iap_entry;


static int iapCommand (iap_calls_t command, int parm1, int parm2, int parm3)
{ // execute ISP similar command via IAP calls.
   iap_entry = (IAP) IAP_LOCATION;
   switch (command) {
...
...
      case IAP_READ_PART_ID:
         command_iap [0] = 54;
         disableIRQ(); iap_entry(command_iap,result_iap); enableIRQ();
         return result_iap[1];
...
...
    }
    return False;
}


=========== snip =================

Regards,

TomW

-- 
Tom Walsh - WN3L - Embedded Systems Consultant
http://openhardware.net, http://cyberiansoftware.com
"Windows? No thanks, I have work to do..."
----------------------------------------------------

At 11:36 PM 1/22/06 -0500, Tom Walsh wrote:
>I dunno, mine works and I didn't bother with ASM:
>
>======== begin C call to ID ============
>
>#define  IAP_LOCATION            0x7ffffff1
>
>typedef void (*IAP)(unsigned int [],unsigned int[]);
>unsigned int command_iap[5], result_iap[3];
>IAP   iap_entry;
>
>
>static int iapCommand (iap_calls_t command, int parm1, int parm2, int parm3)
>{ // execute ISP similar command via IAP calls.
>    iap_entry = (IAP) IAP_LOCATION;
>    switch (command) {
>....
>....
>       case IAP_READ_PART_ID:
>          command_iap [0] = 54;
>          disableIRQ(); iap_entry(command_iap,result_iap); enableIRQ();

That only works if the compiler uses a bx to call iap_entry.  Not all do 
and there is AFAIK nothing that would require a compiler to (keep) doing so.

Robert

" 'Freedom' has no meaning of itself.  There are always restrictions,   be 
they legal, genetic, or physical.  If you don't believe me, try to chew a 
radio signal. "  -- Kelvin Throop, III
http://www.aeolusdevelopment.com/

Robert Adsett wrote:

>At 11:36 PM 1/22/06 -0500, Tom Walsh wrote:
>  
>
>>I dunno, mine works and I didn't bother with ASM:
>>
>>======== begin C call to ID ============
>>
>>#define  IAP_LOCATION            0x7ffffff1
>>
>>typedef void (*IAP)(unsigned int [],unsigned int[]);
>>unsigned int command_iap[5], result_iap[3];
>>IAP   iap_entry;
>>
>>
>>static int iapCommand (iap_calls_t command, int parm1, int parm2, int parm3)
>>{ // execute ISP similar command via IAP calls.
>>   iap_entry = (IAP) IAP_LOCATION;
>>   switch (command) {
>>....
>>....
>>      case IAP_READ_PART_ID:
>>         command_iap [0] = 54;
>>         disableIRQ(); iap_entry(command_iap,result_iap); enableIRQ();
>>    
>>
>
>That only works if the compiler uses a bx to call iap_entry.  Not all do 
>and there is AFAIK nothing that would require a compiler to (keep) doing so.
>
>  
>
Yes, and having a JTAG unit is a good thing!  :-)

TomW

-- 
Tom Walsh - WN3L - Embedded Systems Consultant
http://openhardware.net, http://cyberiansoftware.com
"Windows? No thanks, I have work to do..."
----------------------------------------------------

Thanks guys,

I checked the BX-call several times and debugged even in the the 
THUMB-part. I overlooked however the result comes in Params[1].

Small step voor de ARM, large step for me...

Conrado


--- In lpc2000@yahoogroups.com, Tom Walsh <tom@o...> wrote:
>
> Robert Adsett wrote:
> 
> >At 11:36 PM 1/22/06 -0500, Tom Walsh wrote:
> >  
> >
> >>I dunno, mine works and I didn't bother with ASM:
> >>
> >>======== begin C call to ID ============
> >>
> >>#define  IAP_LOCATION            0x7ffffff1
> >>
> >>typedef void (*IAP)(unsigned int [],unsigned int[]);
> >>unsigned int command_iap[5], result_iap[3];
> >>IAP   iap_entry;
> >>
> >>
> >>static int iapCommand (iap_calls_t command, int parm1, int 
parm2, int parm3)
> >>{ // execute ISP similar command via IAP calls.
> >>   iap_entry = (IAP) IAP_LOCATION;
> >>   switch (command) {
> >>....
> >>....
> >>      case IAP_READ_PART_ID:
> >>         command_iap [0] = 54;
> >>         disableIRQ(); iap_entry(command_iap,result_iap); 
enableIRQ();
> >>    
> >>
> >
> >That only works if the compiler uses a bx to call iap_entry.  Not 
all do 
> >and there is AFAIK nothing that would require a compiler to 
(keep) doing so.

> >
> >  
> >
> Yes, and having a JTAG unit is a good thing!  :-)
> 
> TomW
> 
> -- 
> Tom Walsh - WN3L - Embedded Systems Consultant
> http://openhardware.net, http://cyberiansoftware.com
> "Windows? No thanks, I have work to do..."
> ----------------------------------------------------
>

Hi!
 
>>#define  IAP_LOCATION            0x7ffffff1
                                            ^
>>          disableIRQ(); iap_entry(command_iap,result_iap); enableIRQ();
> That only works if the compiler uses a bx to call iap_entry.  Not all do
> and there is AFAIK nothing that would require a compiler to (keep) doing so.

 Addres of function force compiler to call THUMB mode function.

 Alex