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message32.S revision 1.1 
      1 /*	$NetBSD: message32.S,v 1.1 2009/11/19 22:13:17 dsl Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2003 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by David Laight.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <machine/asm.h>
     33 
     34 /*
     35  * Output messages directly to serial port from 32bit mode.
     36  * Useful for debugging when the real-prot is suspect.
     37  *
     38  * %ds:dump_eax_buff must be somewhere it is safe to write 12 bytes.
     39  */
     40 
     41 #ifndef COM_PORT_VAL
     42 #define COM_PORT_VAL $0x3f8	/* Standard address COM1 (dty0) */
     43 #endif
     44 
     45 	.globl	message32
     46 	.code32
     47 message32:
     48 	pusha
     49 message32_1:
     50 	lodsb
     51 2:
     52 	mov     COM_PORT_VAL, %dx
     53 	outb    %al, %dx
     54 	add     $5, %dl
     55 3:      inb     %dx
     56 	test    $0x40, %al
     57 	jz      3b
     58 
     59 	lodsb
     60 	test    %al, %al
     61 	jnz     2b
     62 	popa
     63 	ret
     64 
     65 	.globl	dump_eax32
     66 dump_eax32:
     67 	pusha
     68 	movl	$dump_eax_buff, %esi
     69 	mov	%esi, %edi
     70 	push	$8
     71 	pop	%ecx
     72 1:	roll	$4, %eax
     73 	push	%eax
     74 	andb	$0x0f, %al
     75 	addb	$0x30, %al			/* 30..3f - clear AF */
     76 #if 1 /* 5 bytes to generate real hex... */
     77 	daa					/* 30..39, 40..45 */
     78 	addb	$0xc0, %al			/* f0..f9, 00..05 */
     79 	adcb	$0x40, %al			/* 30..39, 41..46 */
     80 #endif
     81 	movb	%al,(%edi)
     82 	inc	%edi
     83 	pop	%eax
     84 	loop	1b
     85 	push	$0x20				/* space + 3 NULs */
     86 	pop	(%edi)
     87 	jmp	message32_1
     88