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/* Heap management routines for GNU Emacs on Windows NT.
Copyright (C) 1994 Free Software Foundation, Inc.
This file is part of GNU Emacs.
GNU Emacs is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
GNU Emacs 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNU Emacs; see the file COPYING. If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.
Geoff Voelker (voelker@cs.washington.edu) 7-29-94
*/
#include "config.h"
#include <stdlib.h>
#include <stdio.h>
#include "ntheap.h"
#include "lisp.h" /* for VALMASK */
/* This gives us the page size and the size of the allocation unit on NT. */
SYSTEM_INFO sysinfo_cache;
unsigned long syspage_mask = 0;
/* These are defined to get Emacs to compile, but are not used. */
int edata;
int etext;
/* The major and minor versions of NT. */
int nt_major_version;
int nt_minor_version;
/* Cache information describing the NT system for later use. */
void
cache_system_info (void)
{
union
{
struct info
{
char major;
char minor;
short platform;
} info;
DWORD data;
} version;
/* Cache the version of the operating system. */
version.data = GetVersion ();
nt_major_version = version.info.major;
nt_minor_version = version.info.minor;
/* Cache page size, allocation unit, processor type, etc. */
GetSystemInfo (&sysinfo_cache);
syspage_mask = sysinfo_cache.dwPageSize - 1;
}
/* Round ADDRESS up to be aligned with ALIGN. */
unsigned char *
round_to_next (unsigned char *address, unsigned long align)
{
unsigned long tmp;
tmp = (unsigned long) address;
tmp = (tmp + align - 1) / align;
return (unsigned char *) (tmp * align);
}
/* Info for keeping track of our heap. */
unsigned char *data_region_base = NULL;
unsigned char *data_region_end = NULL;
unsigned char *real_data_region_end = NULL;
unsigned long data_region_size = 0;
unsigned long reserved_heap_size = 0;
/* The start of the data segment. */
unsigned char *
get_data_start (void)
{
return data_region_base;
}
/* The end of the data segment. */
unsigned char *
get_data_end (void)
{
return data_region_end;
}
static char *
allocate_heap (void)
{
/* The base address for our GNU malloc heap is chosen in conjuction
with the link settings for temacs.exe which control the stack size,
the initial default process heap size and the executable image base
address. The link settings and the malloc heap base below must all
correspond; the relationship between these values depends on how NT
and Win95 arrange the virtual address space for a process (and on
the size of the code and data segments in temacs.exe).
The most important thing is to make base address for the executable
image high enough to leave enough room between it and the 4MB floor
of the process address space on Win95 for the primary thread stack,
the process default heap, and other assorted odds and ends
(eg. environment strings, private system dll memory etc) that are
allocated before temacs has a chance to grab its malloc arena. The
malloc heap base can then be set several MB higher than the
executable image base, leaving enough room for the code and data
segments.
Because some parts of Emacs can use rather a lot of stack space
(for instance, the regular expression routines can potentially
allocate several MB of stack space) we allow 8MB for the stack.
Allowing 1MB for the default process heap, and 1MB for odds and
ends, we can base the executable at 16MB and still have a generous
safety margin. At the moment, the executable has about 810KB of
code (for x86) and about 550KB of data - on RISC platforms the code
size could be roughly double, so if we allow 4MB for the executable
we will have plenty of room for expansion.
Thus we would like to set the malloc heap base to 20MB. However,
Win95 refuses to allocate the heap starting at this address, so we
set the base to 27MB to make it happy. Since Emacs now leaves
28 bits available for pointers, this lets us use the remainder of
the region below the 256MB line for our malloc arena - 229MB is
still a pretty decent arena to play in! */
unsigned long base = 0x01B00000; /* 27MB */
unsigned long end = 1 << VALBITS; /* 256MB */
void *ptr = NULL;
#if NTHEAP_PROBE_BASE /* This is never normally defined */
/* Try various addresses looking for one the kernel will let us have. */
while (!ptr && (base < end))
{
reserved_heap_size = end - base;
ptr = VirtualAlloc ((void *) base,
get_reserved_heap_size (),
MEM_RESERVE,
PAGE_NOACCESS);
base += 0x00100000; /* 1MB increment */
}
#else
reserved_heap_size = end - base;
ptr = VirtualAlloc ((void *) base,
get_reserved_heap_size (),
MEM_RESERVE,
PAGE_NOACCESS);
#endif
return ptr;
}
/* Emulate Unix sbrk. */
void *
sbrk (unsigned long increment)
{
void *result;
long size = (long) increment;
/* Allocate our heap if we haven't done so already. */
if (!data_region_base)
{
data_region_base = allocate_heap ();
if (!data_region_base)
return NULL;
/* Ensure that the addresses don't use the upper tag bits since
the Lisp type goes there. */
if (((unsigned long) data_region_base & ~VALMASK) != 0)
{
printf ("Error: The heap was allocated in upper memory.\n");
exit (1);
}
data_region_end = data_region_base;
real_data_region_end = data_region_end;
data_region_size = get_reserved_heap_size ();
}
result = data_region_end;
/* If size is negative, shrink the heap by decommitting pages. */
if (size < 0)
{
int new_size;
unsigned char *new_data_region_end;
size = -size;
/* Sanity checks. */
if ((data_region_end - size) < data_region_base)
return NULL;
/* We can only decommit full pages, so allow for
partial deallocation [cga]. */
new_data_region_end = (data_region_end - size);
new_data_region_end = (unsigned char *)
((long) (new_data_region_end + syspage_mask) & ~syspage_mask);
new_size = real_data_region_end - new_data_region_end;
real_data_region_end = new_data_region_end;
if (new_size > 0)
{
/* Decommit size bytes from the end of the heap. */
if (!VirtualFree (real_data_region_end, new_size, MEM_DECOMMIT))
return NULL;
}
data_region_end -= size;
}
/* If size is positive, grow the heap by committing reserved pages. */
else if (size > 0)
{
/* Sanity checks. */
if ((data_region_end + size) >
(data_region_base + get_reserved_heap_size ()))
return NULL;
/* Commit more of our heap. */
if (VirtualAlloc (data_region_end, size, MEM_COMMIT,
PAGE_READWRITE) == NULL)
return NULL;
data_region_end += size;
/* We really only commit full pages, so record where
the real end of committed memory is [cga]. */
real_data_region_end = (unsigned char *)
((long) (data_region_end + syspage_mask) & ~syspage_mask);
}
return result;
}
/* Recreate the heap from the data that was dumped to the executable.
EXECUTABLE_PATH tells us where to find the executable. */
void
recreate_heap (char *executable_path)
{
unsigned char *tmp;
/* First reserve the upper part of our heap. (We reserve first
because there have been problems in the past where doing the
mapping first has loaded DLLs into the VA space of our heap.) */
tmp = VirtualAlloc ((void *) get_heap_end (),
get_reserved_heap_size () - get_committed_heap_size (),
MEM_RESERVE,
PAGE_NOACCESS);
if (!tmp)
exit (1);
/* We read in the data for the .bss section from the executable
first and map in the heap from the executable second to prevent
any funny interactions between file I/O and file mapping. */
read_in_bss (executable_path);
map_in_heap (executable_path);
}
/* Round the heap up to the given alignment. */
void
round_heap (unsigned long align)
{
unsigned long needs_to_be;
unsigned long need_to_alloc;
needs_to_be = (unsigned long) round_to_next (get_heap_end (), align);
need_to_alloc = needs_to_be - (unsigned long) get_heap_end ();
if (need_to_alloc)
sbrk (need_to_alloc);
}
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.