about summary refs log tree commit diff
path: root/sysdeps/unix/sysv/linux/ia64/getcontext.S
blob: 642ca358d975cb6fc76c5ff25b61d82cfb2ed927 (plain) (blame)
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
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
/* Copyright (C) 2001-2022 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#include <sysdep.h>
#include <features.h>

#include "ucontext_i.h"

/*  __getcontext (ucontext_t *ucp)

  Saves the machine context in UCP such that when it is activated,
  it appears as if __getcontext() returned again.  The only difference
  is that on a first return, r9 contains 1 and on a subsequent
  return, it contains 0.

  This implementation in intended to be used for *synchronous* context
  switches only.  Therefore, it does not have to save anything
  other than the PRESERVED state.  */

ENTRY(__getcontext)
	.prologue
	.body
	alloc r11 = ar.pfs, 1, 0, 4, 0

	// sigprocmask (SIG_BLOCK, NULL, &sc->sc_mask):

	mov r3 = SC_MASK
	mov out0 = SIG_BLOCK

	flushrs					// save dirty partition on rbs
	mov out1 = 0
	add out2 = r3, in0

	mov out3 = 8	// sizeof kernel sigset_t
	DO_CALL(__NR_rt_sigprocmask)

	mov.m rFPSR = ar.fpsr
	mov.m rRSC = ar.rsc
	add r2 = SC_GR+1*8, r32
	;;
	mov.m rBSP = ar.bsp
	.prologue
	.save ar.unat, rUNAT
	mov.m rUNAT = ar.unat
	.body
	add r3 = SC_GR+4*8, r32
	;;

.mem.offset 0,0; st8.spill [r2] = r1, (5*8 - 1*8)
.mem.offset 8,0; st8.spill [r3] = r4, 16
	mov rPFS = r11
	;;
.mem.offset 0,0; st8.spill [r2] = r5, 16
.mem.offset 8,0; st8.spill [r3] = r6, 48
	and rTMP = ~0x3, rRSC
	;;
.mem.offset 0,0; st8.spill [r2] = r7, (SC_FR+2*16-(SC_GR+7*8))
.mem.offset 8,0; st8.spill [r3] = sp, (SC_FR+3*16-(SC_GR+12*8))
	;;
	mov.m ar.rsc = rTMP 		// put RSE into enforced lazy mode
	mov.m rNAT = ar.unat
	mov.i rLC = ar.lc
	;;
	mov.m rRNAT = ar.rnat
	mov.m ar.rsc = rRSC 		// restore RSE mode
	mov rPR = pr

	/*
	 * Rotate NaT bits by rPOS positions to the right:
	 */
	stf.spill [r2] = f2, 32
	stf.spill [r3] = f3, 32
	add rPOS = SC_GR, r32			// rPOS <- &sc_gr[0]
	;;
	stf.spill [r2] = f4, (16*16-4*16)
	stf.spill [r3] = f5, (17*16-5*16)
	extr.u rPOS = rPOS, 3, 6		// get NaT bit number for r0
	;;
	stf.spill [r2] = f16, 32
	stf.spill [r3] = f17, 32
	sub rCPOS = 64, rPOS
	;;
	stf.spill [r2] = f18, 32
	stf.spill [r3] = f19, 32
	shr.u rTMP = rNAT, rPOS
	;;
	stf.spill [r2] = f20, 32
	stf.spill [r3] = f21, 32
	shl rNAT = rNAT, rCPOS
	;;
	stf.spill [r2] = f22, 32
	stf.spill [r3] = f23, 32
	or rNAT = rNAT, rTMP
	;;
	stf.spill [r2] = f24, 32
	stf.spill [r3] = f25, 32
	mov r8 = 0
	;;
	stf.spill [r2] = f26, 32
	stf.spill [r3] = f27, 32
	mov r9 = 1
	;;
	stf.spill [r2] = f28, 32
	stf.spill [r3] = f29, 32
	mov rB0 = b0
	;;
	stf.spill [r2] = f30, 32
	stf.spill [r3] = f31, 32
	mov rB1 = b1
	;;
	mov ar.unat = rUNAT	// we're done spilling integer regs; restore caller's UNaT
	add r2 = SC_NAT, r32
	add r3 = SC_BSP, r32
	;;
	st8 [r2] = rNAT, (SC_RNAT-SC_NAT)
	st8 [r3] = rBSP, (SC_UNAT-SC_BSP)
	mov rB2 = b2
	;;
	st8 [r2] = rRNAT, (SC_FPSR-SC_RNAT)
	st8 [r3] = rUNAT, (SC_PFS-SC_UNAT)
	mov rB3 = b3
	;;
	st8 [r2] = rFPSR, (SC_LC-SC_FPSR)
	st8 [r3] = rPFS, (SC_PR-SC_PFS)
	mov rB4 = b4
	;;
	st8 [r2] = rLC, (SC_BR+0*8-SC_LC)
	st8 [r3] = rPR, (SC_BR+1*8-SC_PR)
	mov rB5 = b5
	;;
	st8 [r2] = rB0, 16
	st8 [r3] = rB1, 16
	;;
	st8 [r2] = rB2, 16
	st8 [r3] = rB3, 16
	;;
	st8 [r2] = rB4
	st8 [r3] = rB5
	ret
END(__getcontext)

weak_alias (__getcontext, getcontext)