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fecd2382 RP |
1 | /* subsegs.c - subsegments - |
2 | Copyright (C) 1987, 1990, 1991 Free Software Foundation, Inc. | |
3 | ||
4 | This file is part of GAS, the GNU Assembler. | |
5 | ||
6 | GAS is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 1, or (at your option) | |
9 | any later version. | |
10 | ||
11 | GAS is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with GAS; see the file COPYING. If not, write to | |
18 | the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ | |
19 | ||
20 | /* static const char rcsid[] = "$Id$"; */ | |
21 | ||
22 | /* | |
23 | * Segments & sub-segments. | |
24 | */ | |
25 | ||
26 | #include "as.h" | |
27 | ||
28 | #include "subsegs.h" | |
29 | #include "obstack.h" | |
30 | ||
31 | frchainS* frchain_root, | |
32 | * frchain_now, /* Commented in "subsegs.h". */ | |
33 | * data0_frchainP; | |
34 | ||
35 | ||
36 | char * const /* in: segT out: char* */ | |
37 | seg_name[] = { | |
38 | "absolute", | |
39 | "text", | |
40 | "data", | |
41 | "bss", | |
42 | "unknown", | |
43 | "absent", | |
44 | "pass1", | |
45 | "ASSEMBLER-INTERNAL-LOGIC-ERROR!", | |
46 | "bignum/flonum", | |
47 | "difference", | |
48 | "debug", | |
49 | "transfert vector preload", | |
50 | "transfert vector postload", | |
51 | "register", | |
52 | "", | |
53 | }; /* Used by error reporters, dumpers etc. */ | |
54 | ||
55 | \f | |
56 | void | |
57 | subsegs_begin() | |
58 | { | |
59 | /* Check table(s) seg_name[], seg_N_TYPE[] is in correct order */ | |
60 | know( SEG_ABSOLUTE == 0 ); | |
61 | know( SEG_TEXT == 1 ); | |
62 | know( SEG_DATA == 2 ); | |
63 | know( SEG_BSS == 3 ); | |
64 | know( SEG_UNKNOWN == 4 ); | |
65 | know( SEG_ABSENT == 5 ); | |
66 | know( SEG_PASS1 == 6 ); | |
67 | know( SEG_GOOF == 7 ); | |
68 | know( SEG_BIG == 8 ); | |
69 | know( SEG_DIFFERENCE == 9 ); | |
70 | know( SEG_DEBUG == 10 ); | |
71 | know( SEG_NTV == 11 ); | |
72 | know( SEG_PTV == 12 ); | |
73 | know( SEG_REGISTER == 13 ); | |
74 | know( SEG_MAXIMUM_ORDINAL == SEG_REGISTER ); | |
75 | know( segment_name (SEG_MAXIMUM_ORDINAL + 1) [0] == 0 ); | |
76 | ||
77 | obstack_begin( &frags, 5000); | |
78 | frchain_root = NULL; | |
79 | frchain_now = NULL; /* Warn new_subseg() that we are booting. */ | |
80 | /* Fake up 1st frag. */ | |
81 | /* It won't be used=> is ok if obstack... */ | |
82 | /* pads the end of it for alignment. */ | |
83 | frag_now=(fragS *)obstack_alloc(&frags,SIZEOF_STRUCT_FRAG); | |
84 | /* obstack_1blank( &frags, SIZEOF_STRUCT_FRAG, & frag_now ); */ | |
85 | /* This 1st frag will not be in any frchain. */ | |
86 | /* We simply give subseg_new somewhere to scribble. */ | |
87 | now_subseg = 42; /* Lie for 1st call to subseg_new. */ | |
88 | subseg_new (SEG_DATA, 0); /* .data 0 */ | |
89 | data0_frchainP = frchain_now; | |
90 | } | |
91 | \f | |
92 | /* | |
93 | * subseg_change() | |
94 | * | |
95 | * Change the subsegment we are in, BUT DO NOT MAKE A NEW FRAG for the | |
96 | * subsegment. If we are already in the correct subsegment, change nothing. | |
97 | * This is used eg as a worker for subseg_new [which does make a new frag_now] | |
98 | * and for changing segments after we have read the source. We construct eg | |
99 | * fixSs even after the source file is read, so we do have to keep the | |
100 | * segment context correct. | |
101 | */ | |
102 | void | |
103 | subseg_change (seg, subseg) | |
104 | register segT seg; | |
105 | register int subseg; | |
106 | { | |
107 | now_seg = seg; | |
108 | now_subseg = subseg; | |
109 | if (seg == SEG_DATA) | |
110 | { | |
111 | seg_fix_rootP = & data_fix_root; | |
112 | seg_fix_tailP = & data_fix_tail; | |
113 | } | |
114 | else | |
115 | { | |
116 | know (seg == SEG_TEXT); | |
117 | seg_fix_rootP = & text_fix_root; | |
118 | seg_fix_tailP = & text_fix_tail; | |
119 | } | |
120 | } | |
121 | \f | |
122 | /* | |
123 | * subseg_new() | |
124 | * | |
125 | * If you attempt to change to the current subsegment, nothing happens. | |
126 | * | |
127 | * In: segT, subsegT code for new subsegment. | |
128 | * frag_now -> incomplete frag for current subsegment. | |
129 | * If frag_now==NULL, then there is no old, incomplete frag, so | |
130 | * the old frag is not closed off. | |
131 | * | |
132 | * Out: now_subseg, now_seg updated. | |
133 | * Frchain_now points to the (possibly new) struct frchain for this | |
134 | * sub-segment. | |
135 | * Frchain_root updated if needed. | |
136 | */ | |
137 | ||
138 | void | |
139 | subseg_new (seg, subseg) /* begin assembly for a new sub-segment */ | |
140 | register segT seg; /* SEG_DATA or SEG_TEXT */ | |
141 | register subsegT subseg; | |
142 | { | |
143 | long tmp; /* JF for obstack alignment hacking */ | |
144 | ||
145 | know( seg == SEG_DATA || seg == SEG_TEXT ); | |
146 | ||
147 | if (seg != now_seg || subseg != now_subseg) | |
148 | { /* we just changed sub-segments */ | |
149 | register frchainS * frcP; /* crawl frchain chain */ | |
150 | register frchainS** lastPP; /* address of last pointer */ | |
151 | frchainS * newP; /* address of new frchain */ | |
152 | register fragS * former_last_fragP; | |
153 | register fragS * new_fragP; | |
154 | ||
155 | if (frag_now) /* If not bootstrapping. */ | |
156 | { | |
157 | frag_now -> fr_fix = obstack_next_free(& frags) - frag_now -> fr_literal; | |
158 | frag_wane(frag_now); /* Close off any frag in old subseg. */ | |
159 | } | |
160 | /* | |
161 | * It would be nice to keep an obstack for each subsegment, if we swap | |
162 | * subsegments a lot. Hence we would have much fewer frag_wanes(). | |
163 | */ | |
164 | { | |
165 | ||
166 | obstack_finish( &frags); | |
167 | /* | |
168 | * If we don't do the above, the next object we put on obstack frags | |
169 | * will appear to start at the fr_literal of the current frag. | |
170 | * Also, above ensures that the next object will begin on a | |
171 | * address that is aligned correctly for the engine that runs | |
172 | * this program. | |
173 | */ | |
174 | } | |
175 | subseg_change (seg, (int)subseg); | |
176 | /* | |
177 | * Attempt to find or make a frchain for that sub seg. | |
178 | * Crawl along chain of frchainSs, begins @ frchain_root. | |
179 | * If we need to make a frchainS, link it into correct | |
180 | * position of chain rooted in frchain_root. | |
181 | */ | |
182 | for (frcP = * (lastPP = & frchain_root); | |
183 | frcP | |
184 | && (int)(frcP -> frch_seg) <= (int)seg; | |
185 | frcP = * ( lastPP = & frcP -> frch_next) | |
186 | ) | |
187 | { | |
188 | if ( (int)(frcP -> frch_seg) == (int)seg | |
189 | && frcP -> frch_subseg >= subseg) | |
190 | { | |
191 | break; | |
192 | } | |
193 | } | |
194 | /* | |
195 | * frcP: Address of the 1st frchainS in correct segment with | |
196 | * frch_subseg >= subseg. | |
197 | * We want to either use this frchainS, or we want | |
198 | * to insert a new frchainS just before it. | |
199 | * | |
200 | * If frcP==NULL, then we are at the end of the chain | |
201 | * of frchainS-s. A NULL frcP means we fell off the end | |
202 | * of the chain looking for a | |
203 | * frch_subseg >= subseg, so we | |
204 | * must make a new frchainS. | |
205 | * | |
206 | * If we ever maintain a pointer to | |
207 | * the last frchainS in the chain, we change that pointer | |
208 | * ONLY when frcP==NULL. | |
209 | * | |
210 | * lastPP: Address of the pointer with value frcP; | |
211 | * Never NULL. | |
212 | * May point to frchain_root. | |
213 | * | |
214 | */ | |
215 | if ( ! frcP | |
216 | || ( (int)(frcP -> frch_seg) > (int)seg | |
217 | || frcP->frch_subseg > subseg)) /* Kinky logic only works with 2 segments. */ | |
218 | { | |
219 | /* | |
220 | * This should be the only code that creates a frchainS. | |
221 | */ | |
222 | newP=(frchainS *)obstack_alloc(&frags,sizeof(frchainS)); | |
223 | /* obstack_1blank( &frags, sizeof(frchainS), &newP); */ | |
224 | /* This begines on a good boundary */ | |
225 | /* because a obstack_done() preceeded it. */ | |
226 | /* It implies an obstack_done(), so we */ | |
227 | /* expect the next object allocated to */ | |
228 | /* begin on a correct boundary. */ | |
229 | *lastPP = newP; | |
230 | newP -> frch_next = frcP; /* perhaps NULL */ | |
231 | (frcP = newP) -> frch_subseg = subseg; | |
232 | newP -> frch_seg = seg; | |
233 | newP -> frch_last = NULL; | |
234 | } | |
235 | /* | |
236 | * Here with frcP ->ing to the frchainS for subseg. | |
237 | */ | |
238 | frchain_now = frcP; | |
239 | /* | |
240 | * Make a fresh frag for the subsegment. | |
241 | */ | |
242 | /* We expect this to happen on a correct */ | |
243 | /* boundary since it was proceeded by a */ | |
244 | /* obstack_done(). */ | |
245 | tmp=obstack_alignment_mask(&frags); /* JF disable alignment */ | |
246 | obstack_alignment_mask(&frags)=0; | |
247 | frag_now=(fragS *)obstack_alloc(&frags,SIZEOF_STRUCT_FRAG); | |
248 | obstack_alignment_mask(&frags)=tmp; | |
249 | /* know( frags . obstack_c_next_free == frag_now -> fr_literal ); */ | |
250 | /* But we want any more chars to come */ | |
251 | /* immediately after the structure we just made. */ | |
252 | new_fragP = frag_now; | |
253 | new_fragP -> fr_next = NULL; | |
254 | /* | |
255 | * Append new frag to current frchain. | |
256 | */ | |
257 | former_last_fragP = frcP -> frch_last; | |
258 | if (former_last_fragP) | |
259 | { | |
260 | know( former_last_fragP -> fr_next == NULL ); | |
261 | know( frchain_now -> frch_root ); | |
262 | former_last_fragP -> fr_next = new_fragP; | |
263 | } | |
264 | else | |
265 | { | |
266 | frcP -> frch_root = new_fragP; | |
267 | } | |
268 | frcP -> frch_last = new_fragP; | |
269 | } /* if (changing subsegments) */ | |
270 | } /* subseg_new() */ | |
271 | ||
272 | /* | |
273 | * Local Variables: | |
274 | * comment-column: 0 | |
275 | * fill-column: 131 | |
276 | * End: | |
277 | */ | |
278 | ||
279 | /* end: subsegs.c */ |