source: trunk/libs/newlib/src/libgloss/mt/crt0-16-002.S @ 498

Last change on this file since 498 was 444, checked in by satin@…, 6 years ago

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

File size: 2.8 KB
Line 
1; crt0_2.s - Startup code for the mrisc1. This code initializes the C
2;              run-time model.
3;
4; Copyright 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
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
17        ; Create a label for the start of the eh_frame section.
18        .section .eh_frame
19__eh_frame_begin:
20
21        .text
22        .global _start
23_start:
24        ;; Initialize the stack pointer
25        ldui    sp, #%hi16(__stack)
26        addui   sp, sp, #%lo16(__stack)
27        or      fp, sp, sp
28        ;; Zero the bss space
29        ldui    r9, #%hi16(__bss_start)
30        addui   r9, r9, #%lo16(__bss_start)
31        ldui    r10, #%hi16(__bss_end)
32        addui   r10, r10, #%lo16(__bss_end)
33        or      r0, r0, r0
34        brle    r10, r9, .Lnext1
35        or      r0, r0, r0
36.Lcpy0:
37        stw     r0, r9, #0
38        addi    r9, r9, #4
39        or      r0, r0, r0      ; nop
40        brle    r9, r10, .Lcpy0
41        or      r0, r0, r0      ; nop
42
43.Lnext1:
44        ;; Copy data from ROM to Frame Buffer (on-chip memory)
45        ldui    r9, #%hi16(_fbdata_start)
46        ori     r9, r9, #%lo16(_fbdata_start)
47        ldui    r10, #%hi16(_fbdata_end)
48        ori     r10, r10, #%lo16(_fbdata_end)
49        ldui    r11, #%hi16(_fbdata_vma)
50        brle    r10, r9, .Lnext2
51        ori     r11, r11, #%lo16(_fbdata_vma)
52.Lcpy1:
53        ldw     r5, r9, #$0
54        addi    r9, r9, #$4
55        stw     r5, r11, #$0
56        brlt    r9, r10, .Lcpy1
57        addi    r11, r11, #$4
58
59.Lnext2:
60        ;; Zero the frame buffer bss section
61        ldui    r9, #%hi16(_fbbss_start)
62        ori     r9, r9, #%lo16(_fbbss_start)
63        ldui    r10, #%hi16(_fbbss_end)
64        ori     r10, r10, #%lo16(_fbbss_end)
65        or      r0, r0, r0
66        brle    r10, r9, .Lnext3
67        or      r0, r0, r0
68.Lcpy2:
69        stw     r0, r9, #$0
70        addi    r9, r9, #$4
71        or      r0, r0, r0
72        brle    r9, r10, .Lcpy2
73        or      r0, r0, r0
74
75.Lnext3:
76        ;; Call global and static constructors
77        ldui    r10, #%hi16(_init)
78        ori     r10, r10, #%lo16(_init)
79        or      r0, r0, r0      ; nop
80        jal     r14, r10
81        or      r0, r0, r0      ; nop
82
83        ;; Call main
84        ldui    r10, #%hi16(main)
85        ori     r10, r10, #%lo16(main)
86        or      r0, r0, r0      ; nop
87        jal     r14, r10
88        or      r0, r0, r0      ; nop
89
90        ;; DJK - Added 12Nov01. Pass main's return value to exit.
91        or      r1, r11, r0
92
93        ;; Jump to exit
94        ldui    r10, #%hi16(exit)
95        ori     r10, r10, #%lo16(exit)
96        or      r0, r0, r0      ; nop
97        jal     r14, r10
98        or      r0, r0, r0      ; nop
99
100        ;; Exit does not return, however, this code is to catch an
101        ;;   error if it does. Set the processor into sleep mode.
102        ori     r1, r0, #$1
103        stw     r1, r0, #%lo16(_DEBUG_HALT_REG)
104        or      r0, r0, r0
105        or      r0, r0, r0
106        or      r0, r0, r0
107        or      r0, r0, r0
108        or      r0, r0, r0
109.Lend:
110        jmp .Lend
111        or      r0, r0, r0
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