Updated the commentary section.
[emacs.git] / src / puresize.h
blob875329c969b99dd4c9fc7dc695dd53d6ea348216
1 /* How much read-only Lisp storage a dumped Emacs needs.
2 Copyright (C) 1993 Free Software Foundation, Inc.
4 This file is part of GNU Emacs.
6 GNU Emacs 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 2, or (at your option)
9 any later version.
11 GNU Emacs 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.
16 You should have received a copy of the GNU General Public License
17 along with GNU Emacs; see the file COPYING. If not, write to
18 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
21 /* Define PURESIZE, the number of bytes of pure Lisp code to leave space for.
23 At one point, this was defined in config.h, meaning that changing
24 PURESIZE would make Make recompile all of Emacs. But only a few
25 files actually use PURESIZE, so we split it out to its own .h file.
27 Make sure to include this file after config.h, since that tells us
28 whether we are running X windows, which tells us how much pure
29 storage to allocate. */
31 /* First define a measure of the amount of data we have. */
33 /* A system configuration file may set this to request a certain extra
34 amount of storage. This is a lot more update-robust that defining
35 BASE_PURESIZE or even PURESIZE directly. */
36 #ifndef SYSTEM_PURESIZE_EXTRA
37 #define SYSTEM_PURESIZE_EXTRA 0
38 #endif
40 #ifndef SITELOAD_PURESIZE_EXTRA
41 #define SITELOAD_PURESIZE_EXTRA 0
42 #endif
44 #ifndef BASE_PURESIZE
45 #define BASE_PURESIZE (650000 + SYSTEM_PURESIZE_EXTRA + SITELOAD_PURESIZE_EXTRA)
46 #endif
48 /* Increase BASE_PURESIZE by a ratio depending on the machine's word size. */
49 #ifndef PURESIZE_RATIO
50 #if VALBITS + GCTYPEBITS + 1 > 32
51 #define PURESIZE_RATIO 8/5 /* Don't surround with `()'. */
52 #else
53 #define PURESIZE_RATIO 1
54 #endif
55 #endif
57 /* This is the actual size in bytes to allocate. */
58 #ifndef PURESIZE
59 #define PURESIZE (BASE_PURESIZE * PURESIZE_RATIO)
60 #endif
62 /* Signal an error if OBJ is pure. */
63 #define CHECK_IMPURE(obj) \
64 { if (PURE_P (obj)) \
65 pure_write_error (); }
67 extern void pure_write_error P_ ((void));
69 /* Define PURE_P. */
71 #ifdef VIRT_ADDR_VARIES
72 /* For machines like APOLLO where text and data can go anywhere
73 in virtual memory. */
75 extern EMACS_INT pure[];
77 #define PURE_P(obj) \
78 ((PNTR_COMPARISON_TYPE) XPNTR (obj) < (PNTR_COMPARISON_TYPE) ((char *) pure + PURESIZE) \
79 && (PNTR_COMPARISON_TYPE) XPNTR (obj) >= (PNTR_COMPARISON_TYPE) pure)
81 #else /* not VIRT_ADDR_VARIES */
82 #ifdef PNTR_COMPARISON_TYPE
83 /* When PNTR_COMPARISON_TYPE is not the default (unsigned int). */
85 extern char my_edata[];
87 #define PURE_P(obj) \
88 ((PNTR_COMPARISON_TYPE) XPNTR (obj) < (PNTR_COMPARISON_TYPE) my_edata)
90 #else /* not VIRT_ADDRESS_VARIES, not PNTR_COMPARISON_TYPE */
92 extern char my_edata[];
94 #define PURE_P(obj) \
95 (XPNTR (obj) < (unsigned int) my_edata)
97 #endif /* PNTR_COMPARISON_TYPE */
98 #endif /* VIRT_ADDRESS_VARIES */