115 lines
3.3 KiB
C
115 lines
3.3 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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* $FreeBSD$
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*/
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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;
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u_int32_t bios_basemem, bios_extmem;
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#ifndef PC98
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#define SMAPSIG 0x534D4150
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struct smap {
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u_int64_t base;
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u_int64_t length;
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u_int32_t type;
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} __packed;
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static struct smap smap;
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#endif
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void
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bios_getmem(void)
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{
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#ifdef PC98
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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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#else
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/* Parse system memory map */
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v86.ebx = 0;
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do {
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v86.ctl = V86_FLAGS;
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v86.addr = 0x15; /* int 0x15 function 0xe820*/
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v86.eax = 0xe820;
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v86.ecx = sizeof(struct smap);
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v86.edx = SMAPSIG;
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v86.es = VTOPSEG(&smap);
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v86.edi = VTOPOFF(&smap);
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v86int();
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if ((v86.efl & 1) || (v86.eax != SMAPSIG))
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break;
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/* look for a low-memory segment that's large enough */
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if ((smap.type == 1) && (smap.base == 0) && (smap.length >= (512 * 1024)))
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bios_basemem = smap.length;
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/* look for the first segment in 'extended' memory */
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if ((smap.type == 1) && (smap.base == 0x100000)) {
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bios_extmem = smap.length;
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}
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} while (v86.ebx != 0);
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/* Fall back to the old compatibility function for base memory */
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if (bios_basemem == 0) {
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v86.ctl = 0;
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v86.addr = 0x12; /* int 0x12 */
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v86int();
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bios_basemem = (v86.eax & 0xffff) * 1024;
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}
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/* Fall back through several compatibility functions for extended memory */
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if (bios_extmem == 0) {
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v86.ctl = V86_FLAGS;
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v86.addr = 0x15; /* int 0x15 function 0xe801*/
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v86.eax = 0xe801;
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v86int();
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if (!(v86.efl & 1)) {
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bios_extmem = ((v86.ecx & 0xffff) + ((v86.edx & 0xffff) * 64)) * 1024;
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}
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}
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if (bios_extmem == 0) {
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v86.ctl = 0;
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v86.addr = 0x15; /* int 0x15 function 0x88*/
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v86.eax = 0x8800;
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v86int();
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bios_extmem = (v86.eax & 0xffff) * 1024;
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}
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#endif
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/* Set memtop to actual top of memory */
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memtop = 0x100000 + bios_extmem;
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}
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