start.s

来自「RTEMS (Real-Time Executive for Multiproc」· S 代码 · 共 152 行

/*
 *  $Id
 */

#include "mrm332.h"
#include "asm.h"
#include <sim.h>

BEGIN_CODE

  /* Put the header necessary for the modified CPU32bug to automatically
     start up rtems: */
#if 0
.long 0xbeefbeef ;
#endif
.long 0 ;
.long start ;

.global start
	start:

	oriw   #0x0700,sr
	movel  #end, d0
	addl   #_StackSize,d0
	movel  d0,sp
	movel  d0,a6


  /* include in ram_init.S */
  /*
   * Initalize the SIM module.
   * The stack pointer is not usable until the RAM chip select lines
   * are configured. The following code must remain inline.
   */

  /* Module Configuration Register */
  /*    see section(s) 3.1.3-3.1.6 of the SIM Reference Manual */
	lea	SIMCR, a0
	movew	#FRZSW,d0
	oriw	#SAM(0,8,SHEN),d0
	oriw	#(MM*SIM_MM),d0
	oriw	#SAM(SIM_IARB,0,IARB),d0
	movew	d0, a0@

	jsr	start_c /* Jump to the C startup code */

END_CODE

#if 0

  /* Synthesizer Control Register */
  /*    see section(s) 4.8 */
  /* end include in ram_init.S */
  *SYNCR = (unsigned short int)
    ( SAM(MRM_W,15,VCO) | SAM(0x0,14,PRESCALE) | SAM(MRM_Y,8,COUNTER) );
  while (! (*SYNCR & SLOCK));	/* protect from clock overshoot */
  /* include in ram_init.S */
  *SYNCR = (unsigned short int)
    ( SAM(MRM_W,15,VCO) | SAM(MRM_X,14,PRESCALE) | SAM(MRM_Y,8,COUNTER) );

  /* System Protection Control Register */
  /*    !!! can only write to once after reset !!! */
  /*    see section 3.8.4 of the SIM Reference Manual */
  *SYPCR = (unsigned char)( HME | BME );

  /* Periodic Interrupr Control Register */
  /*    see section 3.8.2 of the SIM Reference Manual */
  *PICR = (unsigned short int)
    ( SAM(0,8,PIRQL) | SAM(MRM_PIV,0,PIV) );
  /*     ^^^ zero disables interrupt, don't enable here or ram_init will
	 be wrong. It's enabled below. */

  /* Periodic Interrupt Timer Register */
  /*    see section 3.8.3 of the SIM Reference Manual */
  *PITR = (unsigned short int)( SAM(0x09,0,PITM) );
  /*    1.098mS interrupt, assuming 32.768 KHz input clock */

  /* Port C Data */
  /*    load values before enabled */
  *PORTC = (unsigned char) 0x0;

  /* Port E and F Data Register */
  /*    see section 9 of the SIM Reference Manual */
  *PORTE0 = (unsigned char) 0;
  *PORTF0 = (unsigned char) 0;

  /* Port E and F Data Direction Register */
  /*    see section 9 of the SIM Reference Manual */
  *DDRE = (unsigned char) 0xff;
  *DDRF = (unsigned char) 0xfd;
  
  /* Port E and F Pin Assignment Register */
  /*    see section 9 of the SIM Reference Manual */
  *PEPAR = (unsigned char) 0;
  *PFPAR = (unsigned char) 0;

  /* end of SIM initalization code */
  /* end include in ram_init.S */

  /*
   * Initialize RAM by copying the .data section out of ROM (if
   * needed) and "zero-ing" the .bss section.
   */
  {
    register char *src = _etext;
    register char *dst = _copy_start;

    if (_copy_data_from_rom)
      /* ROM has data at end of text; copy it. */
      while (dst < _edata)
	*dst++ = *src++;
    
    /* Zero bss */
    for (dst = _clear_start; dst< end; dst++)
      {
	*dst = 0;
      }
  }

  /*
   * Initialize vector table.
   */
  {
    m68k_isr_entry *monitors_vector_table;

    m68k_get_vbr(monitors_vector_table);

    M68Kvec[  4 ] = monitors_vector_table[  4 ];   /* breakpoints vector */
    M68Kvec[  9 ] = monitors_vector_table[  9 ];   /* trace vector */
    M68Kvec[ 31 ] = monitors_vector_table[ 31 ];   /* level 7 interrupt */
    M68Kvec[ 47 ] = monitors_vector_table[ 47 ];   /* system call vector */
    M68Kvec[ 66 ] = monitors_vector_table[ 66 ];   /* user defined */
    
    m68k_set_vbr(&M68Kvec);
  }

  /*
   * Initalize the board.
   */
  Spurious_Initialize();
  console_init();

  /*
   * Execute main with arguments argc and agrv.
   */
  boot_card(1,__argv);
  reboot();

}

#endif