source: trunk/libs/newlib/src/libgloss/cr16/crt1.S @ 592

Last change on this file since 592 was 444, checked in by satin@…, 6 years ago

add newlib,libalmos-mkh, restructure shared_syscalls.h and mini-libc

File size: 4.0 KB
Line 
1 ##############################################################################
2 # crt0.s -- CR16 default start-up routine                                    #
3 #                                                                            #
4 # Copyright (c) 2004 National Semiconductor Corporation                      #
5 #                                                                            #
6 # The authors hereby grant permission to use, copy, modify, distribute,      #
7 # and license this software and its documentation for any purpose, provided  #
8 # that existing copyright notices are retained in all copies and that this   #
9 # notice is included verbatim in any distributions. No written agreement,    #
10 # license, or royalty fee is required for any of the authorized uses.        #
11 # Modifications to this software may be copyrighted by their authors         #
12 # and need not follow the licensing terms described here, provided that      #
13 # the new terms are clearly indicated on the first page of each file where   #
14 # they apply.                                                                #
15 #                                                                            #
16 # This is the  start routine of your CR16 program.                           #
17 # It is linked with your application automatically. You can use              #
18 # this routine as a template and modify it to your needs, yet this           #
19 # file must be supplied for the compiler.                                    #
20 # It is assumed that the following symbols are defined in your linker        #
21 # script: __STACK_START, __ISTACK_START                                      #
22 ##############################################################################
23
24        .text
25#ifdef __CR16CP__
26        .align 4
27#else
28        .align 2
29#endif
30        .global _main
31        .global _atexit
32        .global _exit
33        .global _start
34        .global __fini
35        .global __init
36        .global __STACK_START
37        .global __ISTACK_START
38
39_start:
40
41 #----------------------------------------------------------------------------#
42 # Initialize the stack pointers. The constants __STACK_START and             #
43 # __ISTACK_START should be defined in the linker script.                     #
44
45        movd    $__STACK_START, (sp)
46
47        movd    $__ISTACK_START, (r1,r0)
48        lprd    (r1,r0), isp
49
50 #----------------------------------------------------------------------------#
51 # Initialize the default sections according to the linker script.            #
52
53#       bal     (ra), __init_bss_data
54
55 #----------------------------------------------------------------------#
56 # Set the Extended Dispatch bit in the CFG register. This is the       #
57 # default configuration for CR16C.                                     #
58
59        spr     cfg, r0                 # Set dispatch table width
60        orw     $0x100, r0
61        lpr     r0, cfg
62
63 #----------------------------------------------------------------------------#
64
65
66 #----------------------------------------------------------------------------#
67 # Handle global and static constructurs execution and setup                  #
68 # destructors to be called from exit.                                        #
69
70        bal     (ra),__init
71        movd    $__fini@c, (r3,r2)
72        bal     (ra), _atexit
73
74 #----------------------------------------------------------------------------#
75 # Jump to the main function in your application.                             #
76
77#ifdef __INT32__
78        movd    $0, (r3,r2) # Number of arguments
79        movd    $0, (r5,r4) # conatins pointer to argument string.
80#else
81        movw    $0, r2      # Number of arguments
82        movd    $0, (r4,r3) # conatins pointer to argument string.
83#endif
84        bal             (ra), _main
85
86 #----------------------------------------------------------------------------#
87 # Upon returning from the main function (if it isn't an infinite loop),      #
88 # jump to the exit function. The exit function is located in the             #
89 # library 'libc.a'.                                                          #
90
91#ifdef __INT32__
92        movd    (r1,r0), (r3,r2) # _main return value gets forwarded.
93#else
94        movw    r0, r2          # _main return value gets forwarded.
95#endif
96        br              _exit           # returns control to the functional simulator.
97
98
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