summaryrefslogtreecommitdiff
path: root/payloads/libpayload/arch/powerpc/head.S
blob: de6edadaff68c49f645824e972c45264523c833c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
/*
 * This file is part of the libpayload project.
 *
 * Copyright (C) 2008 Advanced Micro Devices, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of 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. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 */

	.globl _entry, _leave
	.text
	.align 4

/*
 * Our entry point - assume that the CPU is in 32 bit protected mode and
 * all segments are in a flat model. That's our operating mode, so we won't
 * change anything.
 */
_entry:
#if 0
	call _init

	/* We're back - go back to the bootloader. */
	ret
	.align 4


/*
 * This function saves off the previous stack and switches us to our
 * own execution environment.
 */
_init:
	/* No interrupts, please. */
	cli

	/* Store current stack pointer. */
	movl %esp, %esi

	/* Store EAX and EBX */

	movl %eax,loader_eax
	movl %ebx,loader_ebx

	/* Setup new stack. */
	movl $_stack, %ebx

	movl %ebx, %esp

	/* Save old stack pointer. */
	pushl %esi

	/* Let's rock. */
	call start_main

#endif
	/* %eax has the return value - pass it on unmolested */
_leave:
#if 0
	/* Get old stack pointer. */
	popl %ebx

	/* Restore old stack. */
	movl %ebx, %esp

	/* Return to the original context. */
	ret
#endif