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1a800d321e
Improve the algorithm the loader uses to choose a memory range for its heap when using a range above 1MB. MFC after: 1 week
65 lines
2.2 KiB
C
65 lines
2.2 KiB
C
/*-
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* Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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/*
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* Obtain memory configuration information from the BIOS
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*/
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#include <stand.h>
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#include "libi386.h"
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#include "btxv86.h"
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vm_offset_t memtop, memtop_copyin, high_heap_base;
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uint32_t bios_basemem, bios_extmem, high_heap_size;
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/*
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* The minimum amount of memory to reserve in bios_extmem for the heap.
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*/
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#define HEAP_MIN (3 * 1024 * 1024)
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void
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bios_getmem(void)
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{
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bios_basemem = ((*(u_char *)PTOV(0xA1501) & 0x07) + 1) * 128 * 1024;
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bios_extmem = *(u_char *)PTOV(0xA1401) * 128 * 1024 +
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*(u_int16_t *)PTOV(0xA1594) * 1024 * 1024;
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/* Set memtop to actual top of memory */
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memtop = memtop_copyin = 0x100000 + bios_extmem;
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/*
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* If we have extended memory, use the last 3MB of 'extended' memory
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* as a high heap candidate.
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*/
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if (bios_extmem >= HEAP_MIN) {
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high_heap_size = HEAP_MIN;
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high_heap_base = memtop - HEAP_MIN;
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}
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}
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