sbf_boot_code.s

来自「Freescale MCF5445evb 参考测试代码」· S 代码 · 共 74 行

/*
 * File:    sbf_boot_code.s
 * Purpose: Sample image that is bootable from SBF
 *
 * Notes:   
 *
 */

#ifdef _UNDERSCORE_
#define __SRAM              ___SRAM
#define __SRAM_SIZE         ___SRAM_SIZE
#endif
 
    .extern __SRAM
    .extern __SRAM_SIZE
    .global _asm_startmeup

    .text

/********************************************************************
 *
 * Exception Vector Table
 */
VECTOR_TABLE:
_VECTOR_TABLE:
INITSP:     .long   __SRAM + 0x1000     /* Initial SP */
INITPC:     .long   asm_startmeup       /* Initial PC */

/********************************************************************
 * This is the main entry point upon hard reset.
 */
asm_startmeup:
_asm_startmeup:
    
    /* Initialize 32KByte SRAM */
//    move.l  #__SRAM,d0
//    add.l   #0x221,d0
//    movec   D0,RAMBAR1

    /* Initialize the system */
    move.l  #0x0A000000,d0    
    move.l  d0,0xFC008000   /* CSAR0 */
    move.l  #0x00000001,d0    
    move.l  d0,0xFC008004   /* CSMR0 */
    move.l  #0x08000000,d0    
    move.l  d0,0xFC008018   /* CSAR3 */
    move.l  #0x00000140,d0    
    move.l  d0,0xFC008020   /* CSCR3 */
    move.l  #0x00000001,d0    
    move.l  d0,0xFC00801C   /* CSMR3 */
    
loop1:
    nop
    move.l  #0x00200000,d0
    move.b  #0xFF,d1
    move.b  d1,0x08000005
wait1:
    nop
    subq.l  #1,d0
    bne     wait1
loop2:    
    move.l  #0x00200000,d0
    move.b  #0x00,d1
    move.b  d1,0x08000005
wait2:
    nop
    subq.l  #1,d0
    bne     wait2

    bra     loop1
    
/********************************************************************/
.end