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/*-
* Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* Obtain memory configuration information from the BIOS
*/
#include <stand.h>
#include <machine/pc/bios.h>
#include "libi386.h"
#include "btxv86.h"
vm_offset_t memtop, memtop_copyin, high_heap_base;
uint32_t bios_basemem, bios_extmem, high_heap_size;
static struct bios_smap smap;
/*
* The minimum amount of memory to reserve in bios_extmem for the heap.
*/
#define HEAP_MIN (3 * 1024 * 1024)
void
bios_getmem(void)
{
uint64_t size;
/* Parse system memory map */
v86.ebx = 0;
do {
v86.ctl = V86_FLAGS;
v86.addr = 0x15; /* int 0x15 function 0xe820*/
v86.eax = 0xe820;
v86.ecx = sizeof(struct bios_smap);
v86.edx = SMAP_SIG;
v86.es = VTOPSEG(&smap);
v86.edi = VTOPOFF(&smap);
v86int();
if ((V86_CY(v86.efl)) || (v86.eax != SMAP_SIG))
break;
/* look for a low-memory segment that's large enough */
if ((smap.type == SMAP_TYPE_MEMORY) && (smap.base == 0) &&
(smap.length >= (512 * 1024)))
bios_basemem = smap.length;
/* look for the first segment in 'extended' memory */
if ((smap.type == SMAP_TYPE_MEMORY) && (smap.base == 0x100000)) {
bios_extmem = smap.length;
}
/*
* Look for the largest segment in 'extended' memory beyond
* 1MB but below 4GB.
*/
if ((smap.type == SMAP_TYPE_MEMORY) && (smap.base > 0x100000) &&
(smap.base < 0x100000000ull)) {
size = smap.length;
/*
* If this segment crosses the 4GB boundary, truncate it.
*/
if (smap.base + size > 0x100000000ull)
size = 0x100000000ull - smap.base;
if (size > high_heap_size) {
high_heap_size = size;
high_heap_base = smap.base;
}
}
} while (v86.ebx != 0);
/* Fall back to the old compatibility function for base memory */
if (bios_basemem == 0) {
v86.ctl = 0;
v86.addr = 0x12; /* int 0x12 */
v86int();
bios_basemem = (v86.eax & 0xffff) * 1024;
}
/* Fall back through several compatibility functions for extended memory */
if (bios_extmem == 0) {
v86.ctl = V86_FLAGS;
v86.addr = 0x15; /* int 0x15 function 0xe801*/
v86.eax = 0xe801;
v86int();
if (!(V86_CY(v86.efl))) {
bios_extmem = ((v86.ecx & 0xffff) + ((v86.edx & 0xffff) * 64)) * 1024;
}
}
if (bios_extmem == 0) {
v86.ctl = 0;
v86.addr = 0x15; /* int 0x15 function 0x88*/
v86.eax = 0x8800;
v86int();
bios_extmem = (v86.eax & 0xffff) * 1024;
}
/* Set memtop to actual top of memory */
memtop = memtop_copyin = 0x100000 + bios_extmem;
/*
* If we have extended memory and did not find a suitable heap
* region in the SMAP, use the last 3MB of 'extended' memory as a
* high heap candidate.
*/
if (bios_extmem >= HEAP_MIN && high_heap_size < HEAP_MIN) {
high_heap_size = HEAP_MIN;
high_heap_base = memtop - HEAP_MIN;
}
}
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