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hi, Dear expert:

I follow the steps in https://openrisc.io/newlib/building.html to build my own or1k toolchains.
Now I am trying to use timerrelated functions in $OR1K_ELF/or1k-elf/include/or1k-support.h.

I first start with the example at line 446 in or1k-support.h

void tick_handler(void) {
// Make schedule decision
// and set new thread
or1k_timer_reset();
// End of exception, new thread will run
}
int main() {
// Configure operating system and start threads..
// Configure timer
or1k_timer_init(50);
or1k_timer_set_handler(&tick_handler);
or1k_timer_set_mode(SPR_TTMR_SR);
or1k_timer_enable();
// Schedule first thread and die..
}

But the example failed to pass compile because the define SPR_TTMR_SR is missed.
I try to get the answer from the define of or1k_timer_set_mode.
/*!

• Set timer mode
• The timer has different modes (see architecture manual). The default is to
• automatically restart counting (SPR_TTMR_RT), others are single run
• (SPR_TTMR_SR) and continuous run (SPR_TTMR_CR).
• \param mode a valid mode (use definitions from spr-defs.h as it is important
• that those are also at the correct position in the bit field!)
  */
  void or1k_timer_set_mode(uint32_t mode);

But I still not clear about the value of mode for simple run and continues run.

Please kindly help.

Thanks.

i did ./configure and make then make install its showing like this...>
make[1]: Entering directory '/home/mahadev/or1k/newlib'
/bin/bash ./mkinstalldirs /usr/local /usr/local
make[2]: Entering directory '/home/mahadev/or1k/newlib/etc'
make[2]: Nothing to be done for 'install'.
make[2]: Leaving directory '/home/mahadev/or1k/newlib/etc'
make[1]: Nothing to be done for 'install-target'.
make[1]: Leaving directory '/home/mahadev/or1k/newlib'

hi, Dear expert:
I am trying to use timer interrupt.
So first I need to set the timer period.
There are two functions for this purpose.
int or1k_timer_init (unsigned int hz) 
void or1k_timer_set_period (uint32_t hz)
My question is why this function does not need the input of clock cycles?
if my clock freq is 100Mhz, I think the value should different to clock freq 50Hz.

Thanks.

This is just a minor race condition, but should be fixed: https://github.com/openrisc/newlib/blob/or1k/newlib/libc/sys/or1k/mlock.c#L88

hi, Dear experts:

I am trying to use void or1k_interrupt_enable(int line) to enable just one interrupt.
But it does not work.
I have to use void or1k_interrupts_enable(void) to enable all interrupts.

Looking forward to your reply.

Thanks.

We should not use the SPR_NPC here: https://github.com/openrisc/newlib/blob/or1k/libgloss/or1k/crt0.S#L153

Software should instead always use l.jal and r9, but here it is even simpler: Use the id from the macro. Also needs change in the exception handler then (no address given anymore).

hi, Dear experts:

I tried to enable timer and interrupt at same time.
I add print in timer tick handler function. If I just enable the timer, I can see the print message.
But if I add or1k_interrupts_enable(); then the print message will not seen.

So is there any examples which support timer and interrupt at the same time?

Thanks.

Hi,

Following issue occurs on a mor1kx but I think it may be a toolchain problem.

When defining a byte array and casting parts of the byte array to a DWORD, the address of the first byte of the DWORD is probably not DWORD aligned (i.e. &byte_array[1] = 0x00000001 ). Normally, this is no problem and the DWORD pointer can be dereferenced correctly (i.e. p_u32 = (uint32_t *)&byte_array[1]; a=*p_u32;). When storing the DWORD pointer in a global structure, this does not work, the program simply hangs up when trying to dereference the pointer stored in the global struct. Please find below a program to show the problem. The program works fine compiled with standard gcc on a Linux machine but hangs up in Modelsim simulation when compiled with or1k-elf-gcc.

I am not sure to which branch of Openrisc development it belongs but it may be a toolchain problem as the dereferencing in general works when using the local struct. Also I am not sure if this is already fixed as I use an older (~1 year) version of mor1kx and toolchain.

Best regards,
Markus

#include <stdint.h>
#include <stdio.h>
  
//the structure contains a byte pointer and a DWORD pointer
typedef struct
{
  uint8_t  * p_struct_u8;
  uint32_t * p_struct_u32;
} struct_pointers;
  
//the structure itself as global variable; does not work!
struct_pointers sp;       //comment this line and uncomment the local struct definition to work correctly

int main(int argc, char *argv[])
{
  //10 byte array
  uint8_t v_array_u8 [10] = {1,2,3,4,5,6,7,8,9,10};
  
  //pointer to byte
  uint8_t * p_u8;
  //pointer to DWORD
  uint32_t * p_u32;

  // struct_pointers sp;  //the structure as local variable does work; uncomment this line and comment the global struct definition to work correctly

  //point to first byte (DWORD aligned pointer address)
  p_u8  = &v_array_u8[0];
  p_u32 = (uint32_t *)&v_array_u8[0];
  
  //store the pointers in the struct
  sp.p_struct_u8  = p_u8;
  sp.p_struct_u32 = p_u32;
      
  printf("Addresses of pointers without struct DWORD aligned \n\r");
  printf("p8:   %#010x \n\r", (unsigned int)p_u8);
  printf("p32:  %#010x \n\r", (unsigned int)p_u32);
  printf("Dereferenced pointers without struct \n\r");
  printf("*p8:  %#010x \n\r", (unsigned int)*p_u8);
  printf("*p32: %#010x \n\r", (unsigned int)*p_u32);
  
  printf("Addresses of pointers stored in struct DWORD aligned\n\r");
  printf("sp8:   %#010x \n\r", (unsigned int)sp.p_struct_u8);
  printf("sp32:  %#010x \n\r", (unsigned int)sp.p_struct_u32);
  printf("Dereferenced pointers from struct \n\r");
  printf("*sp8:  %#010x \n\r", (unsigned int)*sp.p_struct_u8);
  printf("*sp32: %#010x \n\r", (unsigned int)*sp.p_struct_u32);
  
  
  //point to second byte (not DWORD aligned pointer address)
  p_u8  = &v_array_u8[1];
  p_u32 = (uint32_t *)&v_array_u8[1];
  
  //store the pointers in the struct
  sp.p_struct_u8  = p_u8;
  sp.p_struct_u32 = p_u32;
    
  printf("Addresses of pointers without struct not DWORD aligned \n\r");
  printf("p8:   %#010x \n\r", (unsigned int)p_u8);
  printf("p32:  %#010x \n\r", (unsigned int)p_u32);
  printf("Dereferenced pointers without struct \n\r");
  printf("*p8:  %#010x \n\r", (unsigned int)*p_u8);
  printf("*p32: %#010x \n\r", (unsigned int)*p_u32);
  
  printf("Addresses of pointers stored in struct not DWORD aligned\n\r");
  printf("sp8:   %#010x \n\r", (unsigned int)sp.p_struct_u8);
  printf("sp32:  %#010x \n\r", (unsigned int)sp.p_struct_u32);
  printf("Dereferenced pointers from struct \n\r");
  printf("*sp8:  %#010x \n\r", (unsigned int)*sp.p_struct_u8);
  printf("*sp32: %#010x \n\r", (unsigned int)*sp.p_struct_u32);   //hangs up here when dereferencing non DWORD aligned address
  
  printf("Successfully finished! \n\r");
  
  while(1) {};
}