[unix-history] / sys / i386 / boot / bios.s

/*
 * Ported to boot 386BSD by Julian Elischer (julian@tfs.com) Sept 1992
 *
 * Mach Operating System
 * Copyright (c) 1992, 1991 Carnegie Mellon University
 * All Rights Reserved.
 * 
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 * 
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 * 
 * Carnegie Mellon requests users of this software to return to
 * 
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 * 
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 */

/*
 * HISTORY
 * $Log:	bios.s,v $
 * Revision 2.2  92/04/04  11:34:26  rpd
 * 	Fix Intel Copyright as per B. Davies authorization.
 * 	[92/04/03            rvb]
 * 	From 2.5 version
 * 	[92/03/30            mg32]
 * 
 * Revision 2.2  91/04/02  14:35:21  mbj
 * 	Add Intel copyright
 * 	[90/02/09            rvb]
 * 
 */


/*
  Copyright 1988, 1989, 1990, 1991, 1992 
   by Intel Corporation, Santa Clara, California.

                All Rights Reserved

Permission to use, copy, modify, and distribute this software and
its documentation for any purpose and without fee is hereby
granted, provided that the above copyright notice appears in all
copies and that both the copyright notice and this permission notice
appear in supporting documentation, and that the name of Intel
not be used in advertising or publicity pertaining to distribution
of the software without specific, written prior permission.

INTEL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
IN NO EVENT SHALL INTEL BE LIABLE FOR ANY SPECIAL, INDIRECT, OR
CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,
NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

	.file	"bios.s"

#include "asm.h"
	.text

/*
# biosread(dev, cyl, head, sec)
#	Read one sector from disk into the internal buffer "intbuf" which
#	is the first 512 bytes of the boot loader.
# BIOS call "INT 0x13 Function 0x2" to read sectors from disk into memory
#	Call with	%ah = 0x2
#			%al = number of sectors
#			%ch = cylinder
#			%cl = sector
#			%dh = head
#			%dl = drive (0x80 for hard disk, 0x0 for floppy disk)
#			%es:%bx = segment:offset of buffer
#	Return:		
#			%al = 0x0 on success; err code on failure
*/

ENTRY(biosread)
	push	%ebp
	mov	%esp, %ebp

	push	%ebx
	push	%ecx
	push	%edx
	push	%es

	movb	0x10(%ebp), %dh
	movw	0x0c(%ebp), %cx
	xchgb	%ch, %cl	# cylinder; the highest 2 bits of cyl is in %cl
	rorb	$2, %cl
	movb	0x14(%ebp), %al
	orb	%al, %cl
	incb	%cl		# sector; sec starts from 1, not 0
	movb	0x8(%ebp), %dl	# device
	xor	%ebx, %ebx	# offset -- 0
				# prot_to_real will set %es to BOOTSEG

	call	EXT(prot_to_real)	# enter real mode
	movb	$0x2, %ah	# subfunction
	movb	$0x1, %al	# number of sectors -- one

	sti
	int	$0x13
	cli

	mov	%eax, %ebx	# save return value

	data16
	call	EXT(real_to_prot) # back to protected mode

	xor	%eax, %eax
	movb	%bh, %al	# return value in %ax

	pop	%es
	pop	%edx
	pop	%ecx
	pop	%ebx
	pop	%ebp

	ret


/*
# putc(ch)
# BIOS call "INT 10H Function 0Eh" to write character to console
#	Call with	%ah = 0x0e
#			%al = character
#			%bh = page
#			%bl = foreground color ( graphics modes)
*/


ENTRY(putc)
	push	%ebp
	mov	%esp, %ebp
	push	%ebx
	push	%ecx

	movb	0x8(%ebp), %cl

	call	EXT(prot_to_real)

	data16
	mov	$0x1, %ebx	# %bh=0, %bl=1 (blue)
	movb	$0xe, %ah
	movb	%cl, %al
	sti
	int	$0x10		# display a byte
	cli

	data16
	call	EXT(real_to_prot)

	pop	%ecx
	pop	%ebx
	pop	%ebp
	ret


/*
# getc()
# BIOS call "INT 16H Function 00H" to read character from keyboard
#	Call with	%ah = 0x0
#	Return:		%ah = keyboard scan code
#			%al = ASCII character
*/

ENTRY(getc)
	push	%ebp
	mov	%esp, %ebp
	push	%ebx		# save %ebx

	call	EXT(prot_to_real)

	movb	$0x0, %ah
	sti
	int	$0x16
	cli

	movb	%al, %bl	# real_to_prot uses %eax

	data16
	call	EXT(real_to_prot)

	xor	%eax, %eax
	movb	%bl, %al

	pop	%ebx
	pop	%ebp
	ret
/*
# ischar()
#       if there is a character pending, return it; otherwise return 0
# BIOS call "INT 16H Function 01H" to check whether a character is pending
#	Call with	%ah = 0x1
#	Return:
#		If key waiting to be input:
#			%ah = keyboard scan code
#			%al = ASCII character
#			Zero flag = clear
#		else
#			Zero flag = set
*/
ENTRY(ischar)
	push	%ebp
	mov	%esp, %ebp
	push	%ebx

	call	EXT(prot_to_real)		# enter real mode

	xor	%ebx, %ebx
	movb	$0x1, %ah
	sti
	int	$0x16
	cli
	data16
	jz	nochar
	movb	%al, %bl

nochar:
	data16
	call	EXT(real_to_prot)

	xor	%eax, %eax
	movb	%bl, %al

	pop	%ebx
	pop	%ebp
	ret

/*
#
# get_diskinfo():  return a word that represents the
#	max number of sectors and  heads and drives for this device
#
*/

ENTRY(get_diskinfo)
	push	%ebp
	mov	%esp, %ebp
	push	%es
	push	%ebx
	push	%ecx
	push	%edx

	movb	0x8(%ebp), %dl		# diskinfo(drive #)
	call	EXT(prot_to_real)	# enter real mode

	movb	$0x8, %ah		# ask for disk info

	sti
	int	$0x13
	cli

	data16
	call	EXT(real_to_prot)	# back to protected mode

	xor	%eax, %eax

	/*form a longword representing all this gunk*/
	movb	%dh, %ah		# # heads
	andb	$0x3f, %cl		# mask of cylinder gunk
	movb	%cl, %al		# # sectors

	pop	%edx
	pop	%ecx
	pop	%ebx
	pop	%es
	pop	%ebp
	ret

/*
#
# memsize(i) :  return the memory size in KB. i == 0 for conventional memory,
#		i == 1 for extended memory
#	BIOS call "INT 12H" to get conventional memory size
#	BIOS call "INT 15H, AH=88H" to get extended memory size
#		Both have the return value in AX.
#
*/

ENTRY(memsize)
	push	%ebp
	mov	%esp, %ebp
	push	%ebx

	mov	8(%ebp), %ebx

	call	EXT(prot_to_real)		# enter real mode

	cmpb	$0x1, %bl
	data16
	je	xext
	
	sti
	int	$0x12
	cli
	data16
	jmp	xdone

xext:	movb	$0x88, %ah
	sti
	int	$0x15
	cli

xdone:
	mov	%eax, %ebx

	data16
	call	EXT(real_to_prot)

	mov	%ebx, %eax
	pop	%ebx
	pop	%ebp
	ret
Commit	Line	Data
15637ed4 RG	1	/*
	2	* Ported to boot 386BSD by Julian Elischer (julian@tfs.com) Sept 1992
	3	*
	4	* Mach Operating System
	5	* Copyright (c) 1992, 1991 Carnegie Mellon University
	6	* All Rights Reserved.
	7	*
	8	* Permission to use, copy, modify and distribute this software and its
	9	* documentation is hereby granted, provided that both the copyright
	10	* notice and this permission notice appear in all copies of the
	11	* software, derivative works or modified versions, and any portions
	12	* thereof, and that both notices appear in supporting documentation.
	13	*
	14	* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
	15	* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
	16	* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
	17	*
	18	* Carnegie Mellon requests users of this software to return to
	19	*
	20	* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
	21	* School of Computer Science
	22	* Carnegie Mellon University
	23	* Pittsburgh PA 15213-3890
	24	*
	25	* any improvements or extensions that they make and grant Carnegie Mellon
	26	* the rights to redistribute these changes.
	27	*/
	28
	29	/*
	30	* HISTORY
	31	* $Log: bios.s,v $
	32	* Revision 2.2 92/04/04 11:34:26 rpd
	33	* Fix Intel Copyright as per B. Davies authorization.
	34	* [92/04/03 rvb]
	35	* From 2.5 version
	36	* [92/03/30 mg32]
	37	*
	38	* Revision 2.2 91/04/02 14:35:21 mbj
	39	* Add Intel copyright
	40	* [90/02/09 rvb]
	41	*
	42	*/
	43
	44
	45	/*
	46	Copyright 1988, 1989, 1990, 1991, 1992
	47	by Intel Corporation, Santa Clara, California.
	48
	49	All Rights Reserved
	50
	51	Permission to use, copy, modify, and distribute this software and
	52	its documentation for any purpose and without fee is hereby
	53	granted, provided that the above copyright notice appears in all
	54	copies and that both the copyright notice and this permission notice
	55	appear in supporting documentation, and that the name of Intel
	56	not be used in advertising or publicity pertaining to distribution
	57	of the software without specific, written prior permission.
	58
	59	INTEL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
	60	INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
	61	IN NO EVENT SHALL INTEL BE LIABLE FOR ANY SPECIAL, INDIRECT, OR
	62	CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
	63	LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,
	64	NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
65	WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
66	*/
67
68	.file "bios.s"
69
70	#include "asm.h"
71	.text
72
73	/*
74	# biosread(dev, cyl, head, sec)
75	# Read one sector from disk into the internal buffer "intbuf" which
76	# is the first 512 bytes of the boot loader.
77	# BIOS call "INT 0x13 Function 0x2" to read sectors from disk into memory
78	# Call with %ah = 0x2
79	# %al = number of sectors
80	# %ch = cylinder
81	# %cl = sector
82	# %dh = head
83	# %dl = drive (0x80 for hard disk, 0x0 for floppy disk)
84	# %es:%bx = segment:offset of buffer
85	# Return:
86	# %al = 0x0 on success; err code on failure
87	*/
88
89	ENTRY(biosread)
90	push %ebp
91	mov %esp, %ebp
92
93	push %ebx
94	push %ecx
95	push %edx
96	push %es
97
98	movb 0x10(%ebp), %dh
99	movw 0x0c(%ebp), %cx
100	xchgb %ch, %cl # cylinder; the highest 2 bits of cyl is in %cl
101	rorb $2, %cl
102	movb 0x14(%ebp), %al
103	orb %al, %cl
104	incb %cl # sector; sec starts from 1, not 0
105	movb 0x8(%ebp), %dl # device
106	xor %ebx, %ebx # offset -- 0
107	# prot_to_real will set %es to BOOTSEG
108
109	call EXT(prot_to_real) # enter real mode
110	movb $0x2, %ah # subfunction
111	movb $0x1, %al # number of sectors -- one
112
113	sti
114	int $0x13
115	cli
116
117	mov %eax, %ebx # save return value
118
119	data16
120	call EXT(real_to_prot) # back to protected mode
121
122	xor %eax, %eax
123	movb %bh, %al # return value in %ax
124
125	pop %es
126	pop %edx
127	pop %ecx
128	pop %ebx
129	pop %ebp
130
131	ret
132
133
134	/*
135	# putc(ch)
136	# BIOS call "INT 10H Function 0Eh" to write character to console
137	# Call with %ah = 0x0e
138	# %al = character
139	# %bh = page
140	# %bl = foreground color ( graphics modes)
141	*/
142
143
144	ENTRY(putc)
145	push %ebp
146	mov %esp, %ebp
147	push %ebx
148	push %ecx
149
150	movb 0x8(%ebp), %cl
151
152	call EXT(prot_to_real)
153
154	data16
155	mov $0x1, %ebx # %bh=0, %bl=1 (blue)
156	movb $0xe, %ah
157	movb %cl, %al
158	sti
159	int $0x10 # display a byte
160	cli
161
162	data16
163	call EXT(real_to_prot)
164
165	pop %ecx
166	pop %ebx
167	pop %ebp
168	ret
169
170
171	/*
172	# getc()
173	# BIOS call "INT 16H Function 00H" to read character from keyboard
174	# Call with %ah = 0x0
175	# Return: %ah = keyboard scan code
176	# %al = ASCII character
177	*/
178
179	ENTRY(getc)
180	push %ebp
181	mov %esp, %ebp
182	push %ebx # save %ebx
183
184	call EXT(prot_to_real)
185
186	movb $0x0, %ah
187	sti
188	int $0x16
189	cli
190
191	movb %al, %bl # real_to_prot uses %eax
192
193	data16
194	call EXT(real_to_prot)
195
196	xor %eax, %eax
197	movb %bl, %al
198
199	pop %ebx
200	pop %ebp
201	ret
202	/*
203	# ischar()
204	# if there is a character pending, return it; otherwise return 0
205	# BIOS call "INT 16H Function 01H" to check whether a character is pending
206	# Call with %ah = 0x1
207	# Return:
208	# If key waiting to be input:
209	# %ah = keyboard scan code
210	# %al = ASCII character
211	# Zero flag = clear
212	# else
213	# Zero flag = set
214	*/
215	ENTRY(ischar)
216	push %ebp
217	mov %esp, %ebp
218	push %ebx
219
220	call EXT(prot_to_real) # enter real mode
221
222	xor %ebx, %ebx
223	movb $0x1, %ah
224	sti
225	int $0x16
226	cli
227	data16
228	jz nochar
229	movb %al, %bl
230
231	nochar:
232	data16
233	call EXT(real_to_prot)
234
235	xor %eax, %eax
236	movb %bl, %al
237
238	pop %ebx
239	pop %ebp
240	ret
241
242	/*
243	#
244	# get_diskinfo(): return a word that represents the
245	# max number of sectors and heads and drives for this device
246	#
247	*/
248
249	ENTRY(get_diskinfo)
250	push %ebp
251	mov %esp, %ebp
252	push %es
253	push %ebx
254	push %ecx
255	push %edx
256
257	movb 0x8(%ebp), %dl # diskinfo(drive #)
258	call EXT(prot_to_real) # enter real mode
259
260	movb $0x8, %ah # ask for disk info
261
262	sti
263	int $0x13
264	cli
265
266	data16
267	call EXT(real_to_prot) # back to protected mode
268
269	xor %eax, %eax
270
271	/form a longword representing all this gunk/
272	movb %dh, %ah # # heads
273	andb $0x3f, %cl # mask of cylinder gunk
274	movb %cl, %al # # sectors
275
276	pop %edx
277	pop %ecx
278	pop %ebx
279	pop %es
280	pop %ebp
281	ret
282
283	/*
284	#
285	# memsize(i) : return the memory size in KB. i == 0 for conventional memory,
286	# i == 1 for extended memory
287	# BIOS call "INT 12H" to get conventional memory size
288	# BIOS call "INT 15H, AH=88H" to get extended memory size
289	# Both have the return value in AX.
290	#
291	*/
292
293	ENTRY(memsize)
294	push %ebp
295	mov %esp, %ebp
296	push %ebx
297
298	mov 8(%ebp), %ebx
299
300	call EXT(prot_to_real) # enter real mode
301
302	cmpb $0x1, %bl
303	data16
304	je xext
305
306	sti
307	int $0x12
308	cli
309	data16
310	jmp xdone
311
312	xext: movb $0x88, %ah
313	sti
314	int $0x15
315	cli
316
317	xdone:
318	mov %eax, %ebx
319
320	data16
321	call EXT(real_to_prot)
322
323	mov %ebx, %eax
324	pop %ebx
325	pop %ebp
326	ret