1/*- 2 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27#include <sys/cdefs.h> 28__FBSDID("$FreeBSD$"); 29 30/* 31 * Obtain memory configuration information from the BIOS 32 */ 33#include <stand.h> 34#include "libi386.h" 35#include "btxv86.h" 36 37vm_offset_t memtop, memtop_copyin, high_heap_base; 38uint32_t bios_basemem, bios_extmem, high_heap_size; 39 40/* 41 * The minimum amount of memory to reserve in bios_extmem for the heap. 42 */ 43#define HEAP_MIN (3 * 1024 * 1024) 44 45void 46bios_getmem(void) 47{ 48 49 bios_basemem = ((*(u_char *)PTOV(0xA1501) & 0x07) + 1) * 128 * 1024; 50 bios_extmem = *(u_char *)PTOV(0xA1401) * 128 * 1024 + 51 *(u_int16_t *)PTOV(0xA1594) * 1024 * 1024; 52 53 /* Set memtop to actual top of memory */ 54 memtop = memtop_copyin = 0x100000 + bios_extmem; 55 56 /* 57 * If we have extended memory, use the last 3MB of 'extended' memory 58 * as a high heap candidate. 59 */ 60 if (bios_extmem >= HEAP_MIN) { 61 high_heap_size = HEAP_MIN; 62 high_heap_base = memtop - HEAP_MIN; 63 } 64} 65