1/*  Special support for trampolines
2 *
3 *   Copyright (C) 1996, 1997, 2000, 2004, 2005 Free Software Foundation, Inc.
4 *   Written By Michael Meissner
5 * 
6 * This file is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the
8 * Free Software Foundation; either version 2, or (at your option) any
9 * later version.
10 * 
11 * In addition to the permissions in the GNU General Public License, the
12 * Free Software Foundation gives you unlimited permission to link the
13 * compiled version of this file with other programs, and to distribute
14 * those programs without any restriction coming from the use of this
15 * file.  (The General Public License restrictions do apply in other
16 * respects; for example, they cover modification of the file, and
17 * distribution when not linked into another program.)
18 * 
19 * This file is distributed in the hope that it will be useful, but
20 * WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
22 * General Public License for more details.
23 * 
24 * You should have received a copy of the GNU General Public License
25 * along with this program; see the file COPYING.  If not, write to
26 * the Free Software Foundation, 51 Franklin Street, Fifth Floor,
27 * Boston, MA 02110-1301, USA.
28 * 
29 *  As a special exception, if you link this library with files
30 *  compiled with GCC to produce an executable, this does not cause the
31 *  resulting executable to be covered by the GNU General Public License.
32 *  This exception does not however invalidate any other reasons why the
33 *  executable file might be covered by the GNU General Public License.
34 */ 
35
36#include "darwin-asm.h"
37
38/* Set up trampolines.  */
39
40.text
41	.align	LOG2_GPR_BYTES
42Ltrampoline_initial:
43	mflr	r0
44	bl	1f
45Lfunc = .-Ltrampoline_initial
46	.g_long	0		/* will be replaced with function address */
47Lchain = .-Ltrampoline_initial
48	.g_long	0		/* will be replaced with static chain */
491:	mflr	r11
50	lg	r12,0(r11)	/* function address */
51	mtlr	r0
52	mtctr	r12
53	lg	r11,GPR_BYTES(r11)	/* static chain */
54	bctr
55
56trampoline_size = .-Ltrampoline_initial
57
58/* R3 = stack address to store trampoline */
59/* R4 = length of trampoline area */
60/* R5 = function address */
61/* R6 = static chain */
62
63	.globl ___trampoline_setup
64___trampoline_setup:
65	mflr	r0		/* save return address */
66        bcl 20,31,LCF0		/* load up __trampoline_initial into r7 */
67LCF0:
68        mflr	r11
69        addis	r7,r11,ha16(LTRAMP-LCF0)
70	lg	r7,lo16(LTRAMP-LCF0)(r7)
71	subi	r7,r7,4
72	li	r8,trampoline_size	/* verify trampoline big enough */
73	cmpg	cr1,r8,r4
74	srwi	r4,r4,2			/* # words to move (insns always 4-byte) */
75	addi	r9,r3,-4	/* adjust pointer for lgu */
76	mtctr	r4
77	blt	cr1,Labort
78
79	mtlr	r0
80
81	/* Copy the instructions to the stack */
82Lmove:
83	lwzu	r10,4(r7)
84	stwu	r10,4(r9)
85	bdnz	Lmove
86
87	/* Store correct function and static chain */
88	stg	r5,Lfunc(r3)
89	stg	r6,Lchain(r3)
90
91	/* Now flush both caches */
92	mtctr	r4
93Lcache:
94	icbi	0,r3
95	dcbf	0,r3
96	addi	r3,r3,4
97	bdnz	Lcache
98
99	/* Ensure cache-flushing has finished.  */
100	sync
101	isync
102
103	/* Make stack writeable.  */
104	b	___enable_execute_stack
105
106Labort:
107#ifdef __DYNAMIC__
108	bl	L_abort$stub
109.data
110.section __TEXT,__picsymbolstub1,symbol_stubs,pure_instructions,32
111	.align 2
112L_abort$stub:
113        .indirect_symbol _abort
114        mflr r0
115        bcl 20,31,L0$_abort
116L0$_abort:
117        mflr r11
118        addis r11,r11,ha16(L_abort$lazy_ptr-L0$_abort)
119        mtlr r0
120	lgu r12,lo16(L_abort$lazy_ptr-L0$_abort)(r11)
121        mtctr r12
122        bctr
123.data
124.lazy_symbol_pointer
125L_abort$lazy_ptr:
126        .indirect_symbol _abort
127	.g_long	dyld_stub_binding_helper
128#else
129	bl	_abort
130#endif
131.data
132	.align LOG2_GPR_BYTES
133LTRAMP:
134	.g_long Ltrampoline_initial
135
136