source: rtems/c/src/lib/libbsp/powerpc/ppcn_60x/start/start.S @ bb7bef4e

4.104.114.84.95
Last change on this file since bb7bef4e was bb7bef4e, checked in by Eric Norum <WENorum@…>, on 10/26/04 at 14:12:06

Remove environ common declaration -- it broke newlib.
  • Property mode set to 100644
File size: 3.6 KB
Line 
1/*
2 * This is based on the mvme-crt0.S file from libgloss/rs6000.
3 * crt0.S -- startup file for PowerPC systems.
4 *
5 * (c) 1998, Radstone Technology plc.
6 *
7 *
8 * This is an unpublished work the copyright  in  which   vests
9 * in  Radstone Technology plc.  All rights reserved.
10 *
11 * The information contained herein is the property of Radstone
12 * Technology  plc.  and  is  supplied  without  liability  for
13 * errors or omissions and no part may be reproduced,  used  or
14 * disclosed except as authorized by contract or  other written
15 * permission.     The    copyright    and    the     foregoing
16 * restriction   on  reproduction, use and disclosure extend to
17 * all  the   media   in   which   this  information   may   be
18 * embodied.
19 *
20 * Copyright (c) 1995 Cygnus Support
21 *
22 * The authors hereby grant permission to use, copy, modify, distribute,
23 * and license this software and its documentation for any purpose, provided
24 * that existing copyright notices are retained in all copies and that this
25 * notice is included verbatim in any distributions. No written agreement,
26 * license, or royalty fee is required for any of the authorized uses.
27 * Modifications to this software may be copyrighted by their authors
28 * and need not follow the licensing terms described here, provided that
29 * the new terms are clearly indicated on the first page of each file where
30 * they apply.
31 *
32 *  $Id$
33 */
34
35#include <ppc-asm.h>
36#include <bsp.h>
37
38        .file   "start.s"
39
40        .extern FUNC_NAME(atexit)
41        .globl  FUNC_NAME(__atexit)
42        .section ".sdata","aw"
43        .align  2
44FUNC_NAME(__atexit):                    /* tell C's eabi-ctor's we have an atexit function */
45        .long   FUNC_NAME(atexit)@fixup /* and that it is to register __do_global_dtors */
46
47        .section ".fixup","aw"
48        .align  2
49        .long   FUNC_NAME(__atexit)
50
51        .text
52        .globl  _start
53        .type   _start,@function
54_start:
55        /* Set MSR */
56        /*
57         * Enable data and instruction address translation and floating point
58         */
59        li      r3,MSR_IR | MSR_DR | MSR_FP
60        mtmsr   r3
61
62        /*
63         * The caches are already flushed by the firmware so just enable
64         */
65        mfspr   r3,HID0
66#if PPC_USE_DATA_CACHE
67        /*
68         * Enable data and instruction cache
69         */
70        ori     r3,r3 ,H0_60X_ICE | H0_60X_DCE
71#else
72        /*
73         * Enable instruction cache only
74         */
75        ori     r3,r3 ,H0_60X_ICE
76#endif
77        mtspr   HID0,r3
78
79        /* clear bss */
80        lis     r6,__bss_start@h
81        ori     r6,r6,__bss_start@l
82        lis     r7,__bss_end@h
83        ori     r7,r7,__bss_end@l
84
85        cmplw   1,r6,r7
86        bc      4,4,.Lbss_done
87
88        subf    r8,r6,r7                /* number of bytes to zero */
89        srwi    r9,r8,2                 /* number of words to zero */
90        mtctr   r9
91        li      r0,0                    /* zero to clear memory */
92        addi    r6,r6,-4                /* adjust so we can use stwu */
93.Lbss_loop:
94        stwu    r0,4(r6)                /* zero bss */
95        bdnz    .Lbss_loop
96
97.Lbss_done:
98
99        /* clear sbss */
100        lis     r6,__sbss_start@h
101        ori     r6,r6,__sbss_start@l
102        lis     r7,__sbss_end@h
103        ori     r7,r7,__sbss_end@l
104
105        cmplw   1,r6,r7
106        bc      4,4,.Lsbss_done
107
108        subf    r8,r6,r7                /* number of bytes to zero */
109        srwi    r9,r8,2                 /* number of words to zero */
110        mtctr   r9
111        li      r0,0                    /* zero to clear memory */
112        addi    r6,r6,-4                /* adjust so we can use stwu */
113.Lsbss_loop:
114        stwu    r0,4(r6)                /* zero sbss */
115        bdnz    .Lsbss_loop
116
117.Lsbss_done:
118
119        lis     sp,__stack@h
120        ori     sp,sp,__stack@l
121
122        /* set up initial stack frame */
123        addi    sp,sp,-4                /* make sure we don't overwrite debug mem */
124        lis     r0,0
125        stw     r0,0(sp)                /* clear back chain */
126        stwu    sp,-56(sp)              /* push another stack frame */
127
128        lis     r5,environ@ha
129        la      r5,environ@l(r5)        /* environp */
130        li      r4, 0                   /* argv */
131        li      r3, 0                   /* argc */
132        /* Let her rip */
133        bl      FUNC_NAME(boot_card)
134
135        /*
136         * This should never get reached
137         */
138        /*
139         * Return MSR to its reset state
140         */
141        li      r3,0
142        mtmsr   r3
143        isync
144
145        /*
146         * Call reset entry point
147         */
148        lis     r3,0xfff0
149        ori     r3,r3,0x100
150        mtlr    r3
151        blr
152.Lstart:
153        .size   _start,.Lstart-_start
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