xref: /src/sys/arch/i386/stand/lib/biosmemps2.S

/*	$NetBSD: biosmemps2.S,v 1.6.30.1 2016/12/05 10:54:53 skrll Exp $	*/

/*
 * Copyright (c) 2003 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jaromir Dolecek.
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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 <machine/asm.h>

	.text

/*
 * int getextmemps2(void *buffer)
 *
 * call int 15 function 0xc7 - later PS/2s - RETURN MEMORY-MAP INFORMATION
 * return: 0=OK, nonzero=error
 * buffer: filled with memory-map table structure
 */
ENTRY(getextmemps2)
	.code32
	movl	%eax,%edx
	xorl	%eax,%eax
	pusha

	call	_C_LABEL(prot_to_real)
	.code16

	/* do int15, function 0xc0 call to discover if C7h is supported */
	movb	$0xc0,%ah
	int	$0x15
	setc	%cl
	jc	out		/* 0xc0 not supported if carry set */

	/* check feature byte 2, bit 4 to see if return memory map is supported */
	movb	%es:6(%bx),%al
	andb	$0x10,%al
	jnz	getmem		/* 0xc7 supported */

	/* set %cl to indicate failure, and exit */
	movb	$2,%cl
	jmp	out

getmem:
	/* move the parameter to right register */
	push	%ds
	movl	%edx,%esi
	andl	$0xf,%esi
	shrl	$4,%edx
	mov	%ds,%ax
	add	%dx,%ax
	mov	%ax,%ds

	/* actually call int15, function 0xc7 now */
	movb	$0xc7,%ah
	int	$0x15
	setc	%cl		/* save carry */
	pop	%ds

out:
	calll	_C_LABEL(real_to_prot)
	.code32

	movb	%cl,28(%esp)
	popa
	ret