Subversion Repositories openrisc_2011-10-31

/*-----------------------------------------------------------------------------
//
// Copyright (c) 2004, 2009 Xilinx, 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:
// 
// 1.  Redistributions source code must retain the above copyright notice,
// this list of conditions and the following disclaimer. 
// 
// 2.  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. 
// 
// 3.  Neither the name of Xilinx 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 HOLDER 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.
//
//---------------------------------------------------------------------------*/

        .file   "xil-crt0.S"
        .section ".got2","aw"
        .align  2

.LCTOC1 = . + 32768

.Lsbss_start = .-.LCTOC1
        .long   __sbss_start

.Lsbss_end = .-.LCTOC1
        .long   __sbss_end

.Lbss_start = .-.LCTOC1
        .long   __bss_start

.Lbss_end = .-.LCTOC1
        .long   __bss_end

.Lstack = .-.LCTOC1
        .long   __stack

.Lsda = .-.LCTOC1
    .long   _SDA_BASE_                      /* address of the first small data area */

.Lsda2 = .-.LCTOC1
    .long   _SDA2_BASE_                     /* address of the second small data area */

    
        .text
        .globl  _start
_start:
        bl      __cpu_init              /* Initialize the CPU first (BSP provides this) */

        lis     5,.LCTOC1@h
        ori     5,5,.LCTOC1@l

        lwz     13,.Lsda(5)             /* load r13 with _SDA_BASE_ address */
        lwz     2,.Lsda2(5)             /* load r2 with _SDA2_BASE_ address */

#ifndef SIMULATOR
        /* clear sbss */
        lwz     6,.Lsbss_start(5)       /* calculate beginning of the SBSS */
        lwz     7,.Lsbss_end(5)         /* calculate end of the SBSS */

        cmplw   1,6,7
        bc      4,4,.Lenclsbss          /* If no SBSS, no clearing required */

        li      0,0                     /* zero to clear memory */
        subf    8,6,7                   /* number of bytes to zero */
        srwi.   9,8,2                   /* number of words to zero */
        beq     .Lstbyteloopsbss        /* Check if the number of bytes was less than 4 */
        mtctr   9        
        addi    6,6,-4                  /* adjust so we can use stwu */
.Lloopsbss:
        stwu    0,4(6)                  /* zero sbss */
        bdnz    .Lloopsbss

.Lstbyteloopsbss:
        andi.   9,8,3                   /* Calculate how many trailing bytes we have */
        beq     0,.Lenclsbss
        mtctr   9
        addi    6,6,-1                  /* adjust, so we can use stbu */

.Lbyteloopsbss:  
        stbu    0,1(6)
        bdnz    .Lbyteloopsbss
    
.Lenclsbss:  
.Lstclbss:
    
        /* clear bss */
        lwz     6,.Lbss_start(5)        /* calculate beginning of the BSS */
        lwz     7,.Lbss_end(5)          /* calculate end of the BSS */

        cmplw   1,6,7
        bc      4,4,.Lenclbss           /* If no BSS, no clearing required */

        li      0,0                     /* zero to clear memory */
        subf    8,6,7                   /* number of bytes to zero */
        srwi.   9,8,2                   /* number of words to zero */
        beq     .Lstbyteloopbss         /* Check if the number of bytes was less than 4 */
        mtctr   9
        addi    6,6,-4                  /* adjust so we can use stwu */
.Lloopbss:
        stwu    0,4(6)                  /* zero bss */
        bdnz    .Lloopbss

.Lstbyteloopbss:    
        andi.   9,8,3                   /* Calculate how many trailing bytes we have */
        beq     0,.Lenclbss             /* If zero, we are done */
        mtctr   9
        addi    6,6,-1                  /* adjust, so we can use stbu */

.Lbyteloopbss:  
        stbu    0,1(6)
        bdnz    .Lbyteloopbss
    
.Lenclbss:
#endif /* SIMULATOR */

        /* set stack pointer */
        lwz     1,.Lstack(5)            /* stack address */

        /* set up initial stack frame */
        addi    1,1,-8                  /* location of back chain */
        lis     0,0
        stw     0,0(1)                  /* set end of back chain */
        
        /* initialize base timer to zero */
        mtspr   0x11c,0
        mtspr   0x11d,0

#ifdef HAVE_XFPU    
        /* On the Xilinx PPC405 and PPC440, the MSR
           must be explicitly set to mark the prescence
           of an FPU */
        mfpvr   0
        rlwinm  0,0,0,12,15
        cmpwi   7,0,8192
        mfmsr   0
        ori     0,0,8192
        beq-    7,fpu_init_done
do_405:
        oris    0,0,512
fpu_init_done:
        mtmsr   0
#endif    
    
#ifdef PROFILING
        /* Setup profiling stuff */
        bl      _profile_init
#endif /* PROFILING */

        /* Call __init */
        bl      __init

        /* Let her rip */
        bl      main

        /* Invoke the language cleanup functions */        
        bl      __fini

#ifdef PROFILING
        /* Cleanup profiling stuff */
        bl      _profile_clean
#endif /* PROFILING */

        /* Call __init */
        /* All done */
        bl      exit
    
/* Trap has been removed for both simulation and hardware */
        .globl _exit
_exit:
        b _exit

.Lstart:
        .size   _start,.Lstart-_start