source: trunk/libs/newlib/src/libgloss/epiphany/crt0.S @ 478

# C Startup for EPIPHANY

# Copyright (c) 2011, Adapteva, Inc.
# All rights reserved.

# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#  * Redistributions of source code must retain the above copyright notice,
#    this list of conditions and the following disclaimer.
#  * Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#  * Neither the name of Adapteva nor the names of its contributors may be
#    used to endorse or promote products derived from this software without
#    specific prior written permission.

# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.


.section IVT,"a",@progbits     ;
        .global _start;
        .type   _start, %function;
_start:
                .balign 4 ;
         b .normal_start

        .balign 4 ; 0x4
         b .sw_exception_v

                .balign 4 ; 0x8
         b .page_miss_v;

                .balign 4 ; 0xc
         b .timer0_expired_v

                .balign 4 ; 0x10
         b .timer1_expired_v

                .balign 4 ; 0x14
                b .message_v

                .balign 4 ; 0x18
                 b .dma0_v

                .balign 4 ; 0x1c
                 b .dma1_v

                .balign 4 ; 0x20
                 b .wand_v

                .balign 4 ; 0x24
                 b .soft_v

.size  _start, .-_start

.section RESERVED_CRT0,"a",@progbits     ;

.global .normal_start;
.balign 4
.type   .normal_start, %function
.normal_start:
        mov  r3,%low(_external_start)
        movt r3,%high(_external_start)
        jalr r3
.size  .normal_start, .-.normal_start




.section .text;
        .org    0x0000                  ; Relative to start of text section
        .global _external_start
        .type   _external_start, %function
_external_start:

        .align  4

        ;; Initialise the stack pointer and frame pointer. Hopefully __stack
        ;; is somewhere meaningful.
        mov     sp,%low(___stack)
        movt    sp,%high(___stack)
        mov     fp,sp

        ;; Zero the data space
        mov     r0,%low(___bss_start)
        movt    r0,%high(___bss_start)
        mov     r1,%low(_end)
        movt    r1,%high(_end)
        mov     r2,#0
        mov     r3,#0
.L0_init_:
        strd    r2,[r0],+#1
        sub     r5,r1,r0
        bne     .L0_init_

        ;;  Setup destructors to be called from exit if main never returns
#if 0
        mov     r0,%low(fini)
        movt    r0,%high(fini)
        mov r2,%low(_atexit)
        movt r2,%high(_atexit)
        jalr r2
#else
        ; calling atexit drags in malloc, so instead poke the function
        ; address directly into the reent structure
        mov     r2,%low(__impure_ptr)
        movt    r2,%high(__impure_ptr)
        ldr     r2,[r2]
        mov     r1,%low(fini)
        movt    r1,%high(fini)
#ifdef __STRUCT_ALIGN_64__
#error
        add     r2,r2,need_to_find_out; &_GLOBAL_REENT->atexit0
        str     r2, [r2,-1];??or -2?; _GLOBAL_REENT->atexit
        mov     r0, 1
        str     r0, [r2,1]      ; _GLOBAL_REENT->atexit0._ind
        str     r1, [r2,2]      ; _GLOBAL_REENT->atexit0._fns[0]
#else  /* !__STRUCT_ALIGN_64__ */
        add     r0,r2,0x14c     ; &_GLOBAL_REENT->atexit0
        str     r0, [r0,-1]     ; _GLOBAL_REENT->atexit
        mov     r0, 1
        strd    r0, [r2,0x2a]   ; _GLOBAL_REENT->atexit0._ind
#endif /* !__STRUCT_ALIGN_64__ */
#endif /* !0 */
        ;; Call global and static constructors
        mov r2,%low(init)
        movt r2,%high(init)
        jalr r2


        ;;return from reset ISR
        mov R0,%low(RDS)
        movt R0,%high(RDS)
        movts iret,r0
        rti
RDS:

        ;;  Initialise argc, argv and envp to empty and call main
        mov     r0,#0
        mov     r1,#0
        mov     r2,#0
        mov r3,%low(_main)
        movt r3,%high(_main)
        jalr r3
        ;;bl    _main

        ;; Call exit
        mov r3,%low(_exit)
        movt r3,%high(_exit)
        jalr r3
        ;;bl    _exit

        ;; Should never reach here
        idle

.size   _external_start, .-_external_start