Subversion Repositories openrisc

/* Initial boot
 *
 * Copyright (c) 2006 CodeSourcery Inc
 *
 * The authors hereby grant permission to use, copy, modify, distribute,
 * and license this software and its documentation for any purpose, provided
 * that existing copyright notices are retained in all copies and that this
 * notice is included verbatim in any distributions. No written agreement,
 * license, or royalty fee is required for any of the authorized uses.
 * Modifications to this software may be copyrighted by their authors
 * and need not follow the licensing terms described here, provided that
 * the new terms are clearly indicated on the first page of each file where
 * they apply.
 */

        #include "asm.h"        
        .text

        .extern __stack
        .extern __heap_end
        .weak __heap_end
        .extern __start1

        /* __reset should cause a HALT in a hosted executable and
           fall into __start for an unhosted executable.  The user is
           free to override this with their own declaration.  */
        .globl __reset
        .weak __reset
__reset:        
#if HOSTED
        HALT
#endif
        
        .globl __start
__start:
        /* Initialize stack */
        move.l IMM(__stack), sp
        move.l IMM(0), fp
        move.l IMM(__heap_end), d1
#if HOSTED
        /* INIT_SIM syscall.  Allows changing sp & d1.  */
        move.l IMM(1),d0

        /* The semihosting sequence is 'nop; halt;sentinel' aligned to
           a 4 byte boundary.  The sentinel is an ill formed instruction
           (movec %sp,0).  The debugger will adjust the pc, so it is never
            executed.  */
        .balignw 4,0x4e71
        nop
        halt
        .long 0x4e7bf000
#endif
        move.l d1,sp@-
        move.l fp,sp@-  /* Dummy return address */
        jmp __start1