src/m/dos386.h

   1 /* Machine description file for MS-DOS
   2
   3    Copyright (C) 1993 Free Software Foundation, Inc.
   4
   5 This file is part of GNU Emacs.
   6
   7 GNU Emacs is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2, or (at your option)
  10 any later version.
  11
  12 GNU Emacs is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GNU Emacs; see the file COPYING.  If not, write to
  19 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  20
  21 /* Note: lots of stuff here was taken from m-dos386.h in demacs. */
  22
  23
  24 /* The following three symbols give information on
  25  the size of various data types.  */
  26
  27 #define SHORTBITS 16            /* Number of bits in a short */
  28 #define INTBITS 32              /* Number of bits in an int */
  29 #define LONGBITS 32             /* Number of bits in a long */
  30
  31 /* Define BIG_ENDIAN iff lowest-numbered byte in a word
  32    is the most significant byte.  */
  33
  34 /* #define BIG_ENDIAN */
  35
  36 /* Define NO_ARG_ARRAY if you cannot take the address of the first of a
  37  * group of arguments and treat it as an array of the arguments.  */
  38
  39 /* #define NO_ARG_ARRAY */
  40
  41 /* Define WORD_MACHINE if addresses and such have
  42  * to be corrected before they can be used as byte counts.  */
  43
  44 /* #define WORD_MACHINE */
  45
  46 /* Define how to take a char and sign-extend into an int.
  47    On machines where char is signed, this is a no-op.  */
  48
  49 #define SIGN_EXTEND_CHAR(c) (c)
  50
  51 /* Now define a symbol for the cpu type, if your compiler
  52    does not define it automatically:
  53    Ones defined so far include vax, m68000, ns16000, pyramid,
  54    orion, tahoe, APOLLO and many others */
  55
  56 #define INTEL386
  57
  58 /* Use type int rather than a union, to represent Lisp_Object */
  59 /* This is desirable for most machines.  */
  60
  61 #define NO_UNION_TYPE
  62
  63 /* Define EXPLICIT_SIGN_EXTEND if XINT must explicitly sign-extend
  64    the 24-bit bit field into an int.  In other words, if bit fields
  65    are always unsigned.
  66
  67    If you use NO_UNION_TYPE, this flag does not matter.  */
  68
  69 #define EXPLICIT_SIGN_EXTEND
  70
  71 /* Data type of load average, as read out of kmem.  */
  72
  73 /* #define LOAD_AVE_TYPE long */
  74
  75 /* Convert that into an integer that is 100 for a load average of 1.0  */
  76
  77 /* #define LOAD_AVE_CVT(x) (int) (((double) (x)) * 100.0 / FSCALE) */
  78
  79 /* Define CANNOT_DUMP on machines where unexec does not work.
  80    Then the function dump-emacs will not be defined
  81    and temacs will do (load "loadup") automatically unless told otherwise.  */
  82
  83 /* #define CANNOT_DUMP */
  84
  85 /* Define VIRT_ADDR_VARIES if the virtual addresses of
  86    pure and impure space as loaded can vary, and even their
  87    relative order cannot be relied on.
  88
  89    Otherwise Emacs assumes that text space precedes data space,
  90    numerically.  */
  91
  92 /* #define VIRT_ADDR_VARIES */
  93
  94 /* Define C_ALLOCA if this machine does not support a true alloca
  95    and the one written in C should be used instead.
  96    Define HAVE_ALLOCA to say that the system provides a properly
  97    working alloca function and it should be used.
  98    Define neither one if an assembler-language alloca
  99    in the file alloca.s should be used.  */
 100
 101 #define HAVE_ALLOCA
 102 #define alloca(x)  __builtin_alloca(x)
 103
 104 /* Define NO_REMAP if memory segmentation makes it not work well
 105    to change the boundary between the text section and data section
 106    when Emacs is dumped.  If you define this, the preloaded Lisp
 107    code will not be sharable; but that's better than failing completely.  */
 108
 109 #define NO_REMAP
 110
 111 /* We need a little extra space, see ../../lisp/loadup.el */
 112 #define PURESIZE 210000