Subversion Repositories openrisc_2011-10-31

        
    .file   "crt0.S"
        
#define XGLUE(a,b) a##b
#define GLUE(a,b) XGLUE(a,b)
        
#ifdef __USER_LABEL_PREFIX__
#define SYM_NAME( name ) GLUE (__USER_LABEL_PREFIX__, name)
#else
#error __USER_LABEL_PREFIX is not defined
#endif

    .text
     /* Setup the assembly entry point.  */
#ifdef __thumb2__
.macro FUNC_START name
        .global \name
        .thumb_func
\name:
.endm
        .syntax unified
        .thumb
#else
.macro FUNC_START name
        .global \name
\name:
.endm
        .code 32
#endif
        FUNC_START SYM_NAME(start)
        FUNC_START SYM_NAME(_start)
        mov     fp, #0  /* Null frame pointer.  */
        mov     r7, #0  /* Null frame pointer for Thumb.  */

        /* Enable interrupts for gdb debugging.  */
#ifdef __thumb2__
        cpsie if
#else
        mrs    r0, cpsr
        bic    r0, r0, #0xC0
        msr    cpsr, r0
#endif
        
        mov     a2, #0                  /* Second arg: fill value.  */
        ldr     a1, .LC1                /* First arg: start of memory block.  */
        ldr     a3, .LC2        
        sub     a3, a3, a1              /* Third arg: length of block.  */

#ifdef  GCRT0
        /* Zero out the bss without using memset. 
           Using memset is bad because it may be instrumented for
           profiling, but at this point, the profiling data structures
           have not been set up. 
           FIXME: This loop could be a lot more efficient.  */
        subs    a3, a3, #0
        beq     2f
1:      strb    a2, [a1]
        subs    a3, a3, #1
        add     a1, a1, #1
        bne     1b
2:      
        /* Nothing to left to clear.  */
#endif

#if defined(__thumb__) && !defined(__thumb2__)  /* Enter Thumb mode. */
        add     a4, pc, #1      /* Get the address of the Thumb block.  */
        bx      a4              /* Go there and start Thumb decoding.   */

        .code 16
        .global __change_mode
        .thumb_func
__change_mode:  
#endif

#ifndef GCRT0
        bl      SYM_NAME(memset)
#endif
        bl      SYM_NAME(__get_memtop)
        sub     r0, r0, #32
        mov     sp, r0

#ifdef __USES_INITFINI__
        /* Some arm/elf targets use the .init and .fini sections
           to create constructors and destructors, and for these
           targets we need to call the _init function and arrange
           for _fini to be called at program exit.  */
        ldr     r0, .Lfini
        bl      SYM_NAME (atexit)
        bl      SYM_NAME (_init)
#endif  

        mov     a1, #0
        ldr     a2, .LC3
        mov     a3, a2
        bl      SYM_NAME(main)
    1:  bl      SYM_NAME(exit)
        b       1b
        .align  2
.LC1:
        .word   __bss_start__
.LC2:
        .word   __bss_end__
.LC3:
        .word   0
#ifdef __USES_INITFINI__
.Lfini:
        .word   SYM_NAME(_fini)
#endif
#if 0
#ifdef __thumb__
        .code 16
#endif
        .global SYM_NAME(__syscall)
#ifdef __thumb__
        .thumb_func
#else
        .align  4
#endif
SYM_NAME(__syscall):
        mov     r12, lr
#ifdef __thumb__
        swi     0x18
#else
        swi     0x180001
#endif
        mov     pc, r12
#endif