mcf5249_lo.s

motorola 针对coldfire 5275 评估板的Dbug bootloader源程序

/*
 * File:    mcf5249_lo.s
 * Purpose: Lowest level routines for mcf5249.
 *
 * Notes:   This file assembles with both Diab and GNU tools
 *
 */

#ifdef _UNDERSCORE_
#define mcf5249_init        _mcf5249_init
#define main                _main
#endif
 
    .extern ___MBAR;
    .extern ___MBAR2;
    .extern ___SRAM0;
    .extern ___SRAM1;
    .extern ___SP_INIT
    .extern mcf5249_init
    .extern main
 
    .global asm_startmeup
    .global _asm_startmeup
 
    .global cpu_cache_flush
    .global _cpu_cache_flush

    .equ    SRAMsize,0x08000

    .text

/********************************************************************/
/*
 * This is the main entry point upon hard reset.
 */
asm_startmeup:
_asm_startmeup:

    /* Initialize RAMBARs: locate SRAM and validate it */
    move.l  #(___SRAM0 + 0x21),d0
    movec   d0,RAMBAR0
    move.l  #(___SRAM1 + 0x21),d0
    movec   d0,RAMBAR1

    /* Point Stack Pointer into SRAM temporarily */
    move.l  #(___SRAM0 + SRAMsize),sp

    /* Initalize MBARs */
    move.l  #(___MBAR + 1),d0
    movec   d0,MBAR
    move.l  #(___MBAR2 + 1),d0
    .long   0x4e7b0C0E      /* movec d0,MBAR2 */

    /* Initialize mcf5249 periphs, etc */
    jsr     mcf5249_init

    /* Relocate Stack Pointer */ 
    move.l  #___SP_INIT,sp

    /* Jump to the main process */
    jmp     main
    
    bra     .
    nop
    nop
    halt

/********************************************************************/
/*
 * The MCF5249 has Icache only 
 */
cpu_cache_flush:
_cpu_cache_flush:
    nop                     /* sync */
    move.l  #0x01000000,d0  /* Invalidate the I-Cache */
    movec d0,cacr
    rts

/********************************************************************/
    .end