1/* Copyright (C) 1991, 93, 96, 97, 98, 99, 2000 Free Software Foundation, Inc.
2   This file is part of the GNU C Library.
3
4   The GNU C Library is free software; you can redistribute it and/or
5   modify it under the terms of the GNU Lesser General Public
6   License as published by the Free Software Foundation; either
7   version 2.1 of the License, or (at your option) any later version.
8
9   The GNU C Library is distributed in the hope that it will be useful,
10   but WITHOUT ANY WARRANTY; without even the implied warranty of
11   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12   Lesser General Public License for more details.
13
14   You should have received a copy of the GNU Lesser General Public
15   License along with the GNU C Library; if not, see
16   <http://www.gnu.org/licenses/>.  */
17
18#include <jmpbuf-offsets.h>
19
20#define ENV(base,reg) [%base + (reg * 4)]
21#define ST_FLUSH_WINDOWS 3
22#define RW_FP [%fp + 0x48]
23
24.global __longjmp
25.type   __longjmp,%function
26.align 4
27__longjmp:
28	.register %g2, #scratch
29	.register %g3, #scratch
30	/* Store our arguments in global registers so we can still
31	 * use them while unwinding frames and their register windows.  */
32
33	ld ENV(o0,JB_FP), %g3	/* Cache target FP in register %g3.  */
34	mov %o0, %g1		/* ENV in %g1 */
35	orcc %o1, %g0, %g2	/* VAL in %g2 */
36	be,a 0f			/* Branch if zero; else skip delay slot.  */
37	mov 1, %g2		/* Delay slot only hit if zero: VAL = 1.  */
380:
39	xor %fp, %g3, %o0
40	add %fp, 512, %o1
41	andncc %o0, 4095, %o0
42	bne .Lthread
43	cmp %o1, %g3
44	bl .Lthread
45
46	/* Now we will loop, unwinding the register windows up the stack
47	 * until the restored %fp value matches the target value in %g3.  */
48
49.Lloop:
50	cmp %fp, %g3		/* Have we reached the target frame? */
51	bl,a .Lloop		/* Loop while current fp is below target.  */
52	 restore		/* Unwind register window in delay slot.  */
53	be,a .Lfound		/* Better have hit it exactly.  */
54	 ld ENV(g1,JB_SP), %o0	/* Delay slot: extract target SP.  */
55
56.Lthread:
57	/*
58	 * Do a "flush register windows trap".  The trap handler in the
59	 * kernel writes all the register windows to their stack slots, and
60	 * marks them all as invalid (needing to be sucked up from the
61	 * stack when used).  This ensures that all information needed to
62	 * unwind to these callers is in memory, not in the register
63	 * windows.
64	 */
65	ta	ST_FLUSH_WINDOWS
66	ld	ENV(g1,JB_PC), %o7 /* Set return PC. */
67	ld	ENV(g1,JB_SP), %fp /* Set saved SP on restore below. */
68	sub	%fp, 64, %sp	/* Allocate a register frame. */
69	st	%g3, RW_FP	/* Set saved FP on restore below. */
70	retl
71	restore %g2, 0, %o0	/* Restore values from above register frame. */
72
73.Lfound:
74	/* We have unwound register windows so %fp matches the target.  */
75	mov %o0, %sp		/* OK, install new SP.  */
76
77.Lsp_ok:
78	ld ENV(g1,JB_PC), %o0	/* Extract target return PC.  */
79	jmp %o0 + 8		/* Return there.  */
80	 mov %g2, %o0		/* Delay slot: set return value.  */
81
82.size __longjmp,.-__longjmp
83
84libc_hidden_def(__longjmp)
85