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e81d98ec | 1 | /* Copyright (C) 1995,1996,1998,2000,2001 Free Software Foundation, Inc. |
0f2d19dd JB |
2 | * |
3 | * This program is free software; you can redistribute it and/or modify | |
4 | * it under the terms of the GNU General Public License as published by | |
5 | * the Free Software Foundation; either version 2, or (at your option) | |
6 | * any later version. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, | |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
11 | * GNU General Public License for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public License | |
14 | * along with this software; see the file COPYING. If not, write to | |
82892bed JB |
15 | * the Free Software Foundation, Inc., 59 Temple Place, Suite 330, |
16 | * Boston, MA 02111-1307 USA | |
0f2d19dd JB |
17 | * |
18 | * As a special exception, the Free Software Foundation gives permission | |
19 | * for additional uses of the text contained in its release of GUILE. | |
20 | * | |
21 | * The exception is that, if you link the GUILE library with other files | |
22 | * to produce an executable, this does not by itself cause the | |
23 | * resulting executable to be covered by the GNU General Public License. | |
24 | * Your use of that executable is in no way restricted on account of | |
25 | * linking the GUILE library code into it. | |
26 | * | |
27 | * This exception does not however invalidate any other reasons why | |
28 | * the executable file might be covered by the GNU General Public License. | |
29 | * | |
30 | * This exception applies only to the code released by the | |
31 | * Free Software Foundation under the name GUILE. If you copy | |
32 | * code from other Free Software Foundation releases into a copy of | |
33 | * GUILE, as the General Public License permits, the exception does | |
34 | * not apply to the code that you add in this way. To avoid misleading | |
35 | * anyone as to the status of such modified files, you must delete | |
36 | * this exception notice from them. | |
37 | * | |
38 | * If you write modifications of your own for GUILE, it is your choice | |
39 | * whether to permit this exception to apply to your modifications. | |
82892bed | 40 | * If you do not wish that, delete this exception notice. */ |
1bbd0b84 | 41 | |
1bbd0b84 | 42 | |
0f2d19dd JB |
43 | \f |
44 | ||
13070bd3 DH |
45 | #include <string.h> |
46 | ||
a0599745 MD |
47 | #include "libguile/_scm.h" |
48 | #include "libguile/root.h" | |
49 | #include "libguile/stackchk.h" | |
5f144b10 GH |
50 | #include "libguile/smob.h" |
51 | #include "libguile/ports.h" | |
52 | #include "libguile/dynwind.h" | |
ce212434 | 53 | #include "libguile/values.h" |
5f144b10 | 54 | |
311df4f0 | 55 | #ifdef DEBUG_EXTENSIONS |
a0599745 | 56 | #include "libguile/debug.h" |
311df4f0 | 57 | #endif |
0f2d19dd | 58 | |
db4b4ca6 | 59 | #include "libguile/validate.h" |
a0599745 | 60 | #include "libguile/continuations.h" |
01c8a3dd | 61 | |
0f2d19dd JB |
62 | \f |
63 | ||
64 | /* {Continuations} | |
65 | */ | |
66 | ||
92c2555f | 67 | scm_t_bits scm_tc16_continuation; |
0f2d19dd | 68 | |
e841c3e0 KN |
69 | static SCM |
70 | continuation_mark (SCM obj) | |
5f144b10 | 71 | { |
92c2555f | 72 | scm_t_contregs *continuation = SCM_CONTREGS (obj); |
01c8a3dd | 73 | |
5f144b10 GH |
74 | scm_gc_mark (continuation->throw_value); |
75 | scm_mark_locations (continuation->stack, continuation->num_stack_items); | |
76 | return continuation->dynenv; | |
77 | } | |
01c8a3dd | 78 | |
1be6b49c | 79 | static size_t |
e841c3e0 | 80 | continuation_free (SCM obj) |
5f144b10 | 81 | { |
92c2555f | 82 | scm_t_contregs *continuation = SCM_CONTREGS (obj); |
5f144b10 | 83 | /* stack array size is 1 if num_stack_items is 0 (rootcont). */ |
1be6b49c | 84 | size_t extra_items = (continuation->num_stack_items > 0) |
5f144b10 GH |
85 | ? (continuation->num_stack_items - 1) |
86 | : 0; | |
92c2555f | 87 | size_t bytes_free = sizeof (scm_t_contregs) |
5f144b10 GH |
88 | + extra_items * sizeof (SCM_STACKITEM); |
89 | ||
90 | scm_must_free (continuation); | |
91 | return bytes_free; | |
92 | } | |
01c8a3dd | 93 | |
e841c3e0 | 94 | static int |
e81d98ec | 95 | continuation_print (SCM obj, SCM port, scm_print_state *state SCM_UNUSED) |
5f144b10 | 96 | { |
92c2555f | 97 | scm_t_contregs *continuation = SCM_CONTREGS (obj); |
5f144b10 GH |
98 | |
99 | scm_puts ("#<continuation ", port); | |
100 | scm_intprint (continuation->num_stack_items, 10, port); | |
101 | scm_puts (" @ ", port); | |
102 | scm_intprint (SCM_CELL_WORD_1 (obj), 16, port); | |
103 | scm_putc ('>', port); | |
104 | return 1; | |
105 | } | |
1cc91f1b | 106 | |
5f144b10 GH |
107 | /* this may return more than once: the first time with the escape |
108 | procedure, then subsequently with the value to be passed to the | |
109 | continuation. */ | |
110 | #define FUNC_NAME "scm_make_continuation" | |
0f2d19dd | 111 | SCM |
5f144b10 | 112 | scm_make_continuation (int *first) |
0f2d19dd | 113 | { |
fcba9b58 | 114 | volatile SCM cont; |
92c2555f MV |
115 | scm_t_contregs *continuation; |
116 | scm_t_contregs *rootcont = SCM_CONTREGS (scm_rootcont); | |
c014a02e | 117 | long stack_size; |
01c8a3dd | 118 | SCM_STACKITEM * src; |
0f2d19dd | 119 | |
f83e2737 | 120 | SCM_ENTER_A_SECTION; |
0f2d19dd | 121 | SCM_FLUSH_REGISTER_WINDOWS; |
5f144b10 | 122 | stack_size = scm_stack_size (rootcont->base); |
92c2555f | 123 | continuation = scm_must_malloc (sizeof (scm_t_contregs) |
5f144b10 GH |
124 | + (stack_size - 1) * sizeof (SCM_STACKITEM), |
125 | FUNC_NAME); | |
126 | continuation->num_stack_items = stack_size; | |
127 | continuation->dynenv = scm_dynwinds; | |
128 | continuation->throw_value = SCM_EOL; | |
129 | continuation->base = src = rootcont->base; | |
130 | continuation->seq = rootcont->seq; | |
0f2d19dd | 131 | #ifdef DEBUG_EXTENSIONS |
5f144b10 | 132 | continuation->dframe = scm_last_debug_frame; |
0f2d19dd | 133 | #endif |
5f144b10 GH |
134 | SCM_NEWSMOB (cont, scm_tc16_continuation, continuation); |
135 | SCM_EXIT_A_SECTION; | |
01c8a3dd | 136 | |
5f144b10 GH |
137 | #ifndef SCM_STACK_GROWS_UP |
138 | src -= stack_size; | |
139 | #endif | |
140 | memcpy (continuation->stack, src, sizeof (SCM_STACKITEM) * stack_size); | |
141 | ||
142 | if (setjmp (continuation->jmpbuf)) | |
143 | { | |
144 | *first = 0; | |
145 | return continuation->throw_value; | |
146 | } | |
147 | else | |
148 | { | |
149 | *first = 1; | |
150 | return cont; | |
151 | } | |
0f2d19dd | 152 | } |
5f144b10 | 153 | #undef FUNC_NAME |
0f2d19dd | 154 | |
5f144b10 | 155 | static void scm_dynthrow (SCM, SCM); |
01c8a3dd DH |
156 | |
157 | /* Grow the stack by a fixed amount to provide space to copy in the | |
158 | * continuation. Possibly this function has to be called several times | |
159 | * recursively before enough space is available. Make sure the compiler does | |
160 | * not optimize the growth array away by storing it's address into a global | |
161 | * variable. | |
162 | */ | |
163 | ||
92c2555f | 164 | scm_t_bits scm_i_dummy; |
1cc91f1b | 165 | |
0f2d19dd | 166 | static void |
01c8a3dd DH |
167 | grow_stack (SCM cont, SCM val) |
168 | { | |
92c2555f | 169 | scm_t_bits growth[100]; |
01c8a3dd | 170 | |
92c2555f | 171 | scm_i_dummy = (scm_t_bits) growth; |
01c8a3dd | 172 | scm_dynthrow (cont, val); |
0f2d19dd | 173 | } |
0f2d19dd | 174 | |
1cc91f1b | 175 | |
01c8a3dd DH |
176 | /* Copy the continuation stack into the current stack. Calling functions from |
177 | * within this function is safe, since only stack frames below this function's | |
178 | * own frame are overwritten. Thus, memcpy can be used for best performance. | |
179 | */ | |
180 | static void | |
92c2555f | 181 | copy_stack_and_call (scm_t_contregs *continuation, SCM val, |
5f144b10 | 182 | SCM_STACKITEM * dst) |
0f2d19dd | 183 | { |
5f144b10 GH |
184 | memcpy (dst, continuation->stack, |
185 | sizeof (SCM_STACKITEM) * continuation->num_stack_items); | |
01c8a3dd DH |
186 | |
187 | #ifdef DEBUG_EXTENSIONS | |
5f144b10 | 188 | scm_last_debug_frame = continuation->dframe; |
0f2d19dd | 189 | #endif |
01c8a3dd | 190 | |
5f144b10 GH |
191 | continuation->throw_value = val; |
192 | longjmp (continuation->jmpbuf, 1); | |
01c8a3dd DH |
193 | } |
194 | ||
195 | ||
196 | /* Call grow_stack until the stack space is large enough, then, as the current | |
197 | * stack frame might get overwritten, let copy_stack_and_call perform the | |
198 | * actual copying and continuation calling. | |
199 | */ | |
200 | static void | |
201 | scm_dynthrow (SCM cont, SCM val) | |
202 | { | |
92c2555f | 203 | scm_t_contregs *continuation = SCM_CONTREGS (cont); |
01c8a3dd DH |
204 | SCM_STACKITEM * dst = SCM_BASE (scm_rootcont); |
205 | SCM_STACKITEM stack_top_element; | |
206 | ||
0f2d19dd | 207 | #ifdef SCM_STACK_GROWS_UP |
5f144b10 | 208 | if (SCM_PTR_GE (dst + continuation->num_stack_items, &stack_top_element)) |
01c8a3dd | 209 | grow_stack (cont, val); |
0f2d19dd | 210 | #else |
5f144b10 GH |
211 | dst -= continuation->num_stack_items; |
212 | if (SCM_PTR_LE (dst, &stack_top_element)) | |
01c8a3dd | 213 | grow_stack (cont, val); |
0f2d19dd | 214 | #endif /* def SCM_STACK_GROWS_UP */ |
01c8a3dd | 215 | |
5f144b10 GH |
216 | SCM_FLUSH_REGISTER_WINDOWS; |
217 | copy_stack_and_call (continuation, val, dst); | |
0f2d19dd JB |
218 | } |
219 | ||
db4b4ca6 DH |
220 | |
221 | static SCM | |
222 | continuation_apply (SCM cont, SCM args) | |
5f144b10 | 223 | #define FUNC_NAME "continuation_apply" |
0f2d19dd | 224 | { |
92c2555f MV |
225 | scm_t_contregs *continuation = SCM_CONTREGS (cont); |
226 | scm_t_contregs *rootcont = SCM_CONTREGS (scm_rootcont); | |
5f144b10 | 227 | |
5f144b10 GH |
228 | if (continuation->seq != rootcont->seq |
229 | /* this base comparison isn't needed */ | |
230 | || continuation->base != rootcont->base) | |
231 | { | |
db4b4ca6 | 232 | SCM_MISC_ERROR ("continuation from wrong top level: ~S", |
1afff620 | 233 | scm_list_1 (cont)); |
5f144b10 | 234 | } |
0f2d19dd | 235 | |
5f144b10 | 236 | scm_dowinds (continuation->dynenv, |
5bd44fc9 GH |
237 | scm_ilength (scm_dynwinds) |
238 | - scm_ilength (continuation->dynenv)); | |
0f2d19dd | 239 | |
ce212434 | 240 | scm_dynthrow (cont, scm_values (args)); |
0f2d19dd JB |
241 | return SCM_UNSPECIFIED; /* not reached */ |
242 | } | |
5f144b10 | 243 | #undef FUNC_NAME |
0f2d19dd | 244 | |
db4b4ca6 | 245 | |
0f2d19dd JB |
246 | void |
247 | scm_init_continuations () | |
0f2d19dd | 248 | { |
5f144b10 GH |
249 | scm_tc16_continuation = scm_make_smob_type ("continuation", 0); |
250 | scm_set_smob_mark (scm_tc16_continuation, continuation_mark); | |
251 | scm_set_smob_free (scm_tc16_continuation, continuation_free); | |
252 | scm_set_smob_print (scm_tc16_continuation, continuation_print); | |
253 | scm_set_smob_apply (scm_tc16_continuation, continuation_apply, 0, 0, 1); | |
8dc9439f | 254 | #ifndef SCM_MAGIC_SNARFER |
a0599745 | 255 | #include "libguile/continuations.x" |
8dc9439f | 256 | #endif |
0f2d19dd JB |
257 | } |
258 | ||
89e00824 ML |
259 | /* |
260 | Local Variables: | |
261 | c-file-style: "gnu" | |
262 | End: | |
263 | */ |