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

/*
 * 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.
 *
 *	from: Mach, Revision 2.2  92/04/04  11:34:26  rpd
 *	$Id$
 */

/*
  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, nsec, offset)
#	Read "nsec" sectors from disk to offset "offset" in boot segment
# 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
	movl	0x1c(%ebp), %ebx	# offset
				# prot_to_real will set %es to BOOTSEG

	call	EXT(prot_to_real)	# enter real mode
	movb	$0x2, %ah	# subfunction
	addr32
	movb	0x18(%ebp), %al	# number of sectors

	sti
	int	$0x13
	cli

	mov	%eax, %ebx	# save return value (actually movw %ax, %bx)

	data32
	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)

	data32
	mov	$0x1, %ebx	# %bh=0, %bl=1 (blue)
	movb	$0xe, %ah
	movb	%cl, %al
	sti
	int	$0x10		# display a byte
	cli

	data32
	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

	data32
	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
	data32
	jz	nochar
	movb	%al, %bl

nochar:
	data32
	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

	jnc	ok
	/*
	 * Urk.  Call failed.  It is not supported for floppies by old BIOS's.
	 * Guess it's a 15-sector floppy.  Initialize all the registers for
	 * documentation, although we only need head and sector counts.
	 */
	subb	%ah, %ah		# %ax = 0
	movb	%al, %al
	movb	%ah, %bh		# %bh = 0
	movb	$2, %bl			# %bl bits 0-3 = drive type, 2 = 1.2M
	movb	$79, %ch		# max track
	movb	$15, %cl		# max sector
	movb	$1, %dh			# max head
	movb	$1, %dl			# # floppy drives installed
	# es:di = parameter table
	# carry = 0
ok:

	data32
	call	EXT(real_to_prot)	# back to protected mode

	xor	%eax, %eax

	/*form a longword representing all this gunk*/
	movb	%dh, %ah		# max head
	andb	$0x3f, %cl		# mask of cylinder gunk
	movb	%cl, %al		# max sector (and # 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
	data32
	je	xext
	
	sti
	int	$0x12
	cli
	data32
	jmp	xdone

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

xdone:
	mov	%eax, %ebx

	data32
	call	EXT(real_to_prot)

	mov	%ebx, %eax
	pop	%ebx
	pop	%ebp
	ret
Commit	Line	Data
a27f4645	1	/*
a27f4645 RM	2	* Mach Operating System
	3	* Copyright (c) 1992, 1991 Carnegie Mellon University
	4	* All Rights Reserved.
	5	*
	6	* Permission to use, copy, modify and distribute this software and its
	7	* documentation is hereby granted, provided that both the copyright
	8	* notice and this permission notice appear in all copies of the
	9	* software, derivative works or modified versions, and any portions
	10	* thereof, and that both notices appear in supporting documentation.
	11	*
	12	* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
	13	* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
	14	* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
	15	*
	16	* Carnegie Mellon requests users of this software to return to
	17	*
	18	* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
	19	* School of Computer Science
	20	* Carnegie Mellon University
	21	* Pittsburgh PA 15213-3890
	22	*
	23	* any improvements or extensions that they make and grant Carnegie Mellon
	24	* the rights to redistribute these changes.
a27f4645	25	*
e4270b63 RG	26	* from: Mach, Revision 2.2 92/04/04 11:34:26 rpd
e4270b63 RG	27	* $Id$
a27f4645 RM	28	*/
a27f4645 RM	29
a27f4645 RM	30	/*
	31	Copyright 1988, 1989, 1990, 1991, 1992
	32	by Intel Corporation, Santa Clara, California.
	33
	34	All Rights Reserved
	35
	36	Permission to use, copy, modify, and distribute this software and
	37	its documentation for any purpose and without fee is hereby
	38	granted, provided that the above copyright notice appears in all
	39	copies and that both the copyright notice and this permission notice
	40	appear in supporting documentation, and that the name of Intel
	41	not be used in advertising or publicity pertaining to distribution
	42	of the software without specific, written prior permission.
	43
	44	INTEL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
	45	INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
	46	IN NO EVENT SHALL INTEL BE LIABLE FOR ANY SPECIAL, INDIRECT, OR
	47	CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
	48	LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,
	49	NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
	50	WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
	51	*/
	52
	53	.file "bios.s"
	54
	55	#include "asm.h"
	56	.text
	57
	58	/*
	59	# biosread(dev, cyl, head, sec, nsec, offset)
	60	# Read "nsec" sectors from disk to offset "offset" in boot segment
	61	# BIOS call "INT 0x13 Function 0x2" to read sectors from disk into memory
	62	# Call with %ah = 0x2
	63	# %al = number of sectors
	64	# %ch = cylinder
	65	# %cl = sector
	66	# %dh = head
	67	# %dl = drive (0x80 for hard disk, 0x0 for floppy disk)
	68	# %es:%bx = segment:offset of buffer
	69	# Return:
	70	# %al = 0x0 on success; err code on failure
	71	*/
	72
	73	ENTRY(biosread)
	74	push %ebp
	75	mov %esp, %ebp
	76
	77	push %ebx
	78	push %ecx
	79	push %edx
	80	push %es
	81
	82	movb 0x10(%ebp), %dh
	83	movw 0x0c(%ebp), %cx
	84	xchgb %ch, %cl # cylinder; the highest 2 bits of cyl is in %cl
	85	rorb $2, %cl
	86	movb 0x14(%ebp), %al
	87	orb %al, %cl
	88	incb %cl # sector; sec starts from 1, not 0
	89	movb 0x8(%ebp), %dl # device
	90	movl 0x1c(%ebp), %ebx # offset
	91	# prot_to_real will set %es to BOOTSEG
	92
	93	call EXT(prot_to_real) # enter real mode
94	movb $0x2, %ah # subfunction
95	addr32
96	movb 0x18(%ebp), %al # number of sectors
97
98	sti
99	int $0x13
100	cli
101
102	mov %eax, %ebx # save return value (actually movw %ax, %bx)
103
104	data32
105	call EXT(real_to_prot) # back to protected mode
106
107	xor %eax, %eax
108	movb %bh, %al # return value in %ax
109
110	pop %es
111	pop %edx
112	pop %ecx
113	pop %ebx
114	pop %ebp
115
116	ret
117
118
119	/*
120	# putc(ch)
121	# BIOS call "INT 10H Function 0Eh" to write character to console
122	# Call with %ah = 0x0e
123	# %al = character
124	# %bh = page
125	# %bl = foreground color ( graphics modes)
126	*/
127
128
129	ENTRY(putc)
130	push %ebp
131	mov %esp, %ebp
132	push %ebx
133	push %ecx
134
135	movb 0x8(%ebp), %cl
136
137	call EXT(prot_to_real)
138
139	data32
140	mov $0x1, %ebx # %bh=0, %bl=1 (blue)
141	movb $0xe, %ah
142	movb %cl, %al
143	sti
144	int $0x10 # display a byte
145	cli
146
147	data32
148	call EXT(real_to_prot)
149
150	pop %ecx
151	pop %ebx
152	pop %ebp
153	ret
154
155
156	/*
157	# getc()
158	# BIOS call "INT 16H Function 00H" to read character from keyboard
159	# Call with %ah = 0x0
160	# Return: %ah = keyboard scan code
161	# %al = ASCII character
162	*/
163
164	ENTRY(getc)
165	push %ebp
166	mov %esp, %ebp
167	push %ebx # save %ebx
168
169	call EXT(prot_to_real)
170
171	movb $0x0, %ah
172	sti
173	int $0x16
174	cli
175
176	movb %al, %bl # real_to_prot uses %eax
177
178	data32
179	call EXT(real_to_prot)
180
181	xor %eax, %eax
182	movb %bl, %al
183
184	pop %ebx
185	pop %ebp
186	ret
187	/*
188	# ischar()
189	# if there is a character pending, return it; otherwise return 0
190	# BIOS call "INT 16H Function 01H" to check whether a character is pending
191	# Call with %ah = 0x1
192	# Return:
193	# If key waiting to be input:
194	# %ah = keyboard scan code
195	# %al = ASCII character
196	# Zero flag = clear
197	# else
198	# Zero flag = set
199	*/
200	ENTRY(ischar)
201	push %ebp
202	mov %esp, %ebp
203	push %ebx
204
205	call EXT(prot_to_real) # enter real mode
206
207	xor %ebx, %ebx
208	movb $0x1, %ah
209	sti
210	int $0x16
211	cli
212	data32
213	jz nochar
214	movb %al, %bl
215
216	nochar:
217	data32
218	call EXT(real_to_prot)
219
220	xor %eax, %eax
221	movb %bl, %al
222
223	pop %ebx
224	pop %ebp
225	ret
226
227	/*
228	#
229	# get_diskinfo(): return a word that represents the
230	# max number of sectors and heads and drives for this device
231	#
232	*/
233
234	ENTRY(get_diskinfo)
235	push %ebp
236	mov %esp, %ebp
237	push %es
238	push %ebx
239	push %ecx
240	push %edx
241
242	movb 0x8(%ebp), %dl # diskinfo(drive #)
243	call EXT(prot_to_real) # enter real mode
244
245	movb $0x8, %ah # ask for disk info
246
247	sti
248	int $0x13
249	cli
250
251	jnc ok
252	/*
253	* Urk. Call failed. It is not supported for floppies by old BIOS's.
254	* Guess it's a 15-sector floppy. Initialize all the registers for
255	* documentation, although we only need head and sector counts.
256	*/
257	subb %ah, %ah # %ax = 0
258	movb %al, %al
259	movb %ah, %bh # %bh = 0
260	movb $2, %bl # %bl bits 0-3 = drive type, 2 = 1.2M
261	movb $79, %ch # max track
262	movb $15, %cl # max sector
263	movb $1, %dh # max head
264	movb $1, %dl # # floppy drives installed
265	# es:di = parameter table
266	# carry = 0
267	ok:
268
269	data32
270	call EXT(real_to_prot) # back to protected mode
271
272	xor %eax, %eax
273
274	/form a longword representing all this gunk/
275	movb %dh, %ah # max head
276	andb $0x3f, %cl # mask of cylinder gunk
277	movb %cl, %al # max sector (and # sectors)
278
279	pop %edx
280	pop %ecx
281	pop %ebx
282	pop %es
283	pop %ebp
284	ret
285
286	/*
287	#
288	# memsize(i) : return the memory size in KB. i == 0 for conventional memory,
289	# i == 1 for extended memory
290	# BIOS call "INT 12H" to get conventional memory size
291	# BIOS call "INT 15H, AH=88H" to get extended memory size
292	# Both have the return value in AX.
293	#
294	*/
295
296	ENTRY(memsize)
297	push %ebp
298	mov %esp, %ebp
299	push %ebx
300
301	mov 8(%ebp), %ebx
302
303	call EXT(prot_to_real) # enter real mode
304
305	cmpb $0x1, %bl
306	data32
307	je xext
308
309	sti
310	int $0x12
311	cli
312	data32
313	jmp xdone
314
315	xext: movb $0x88, %ah
316	sti
317	int $0x15
318	cli
319
320	xdone:
321	mov %eax, %ebx
322
323	data32
324	call EXT(real_to_prot)
325
326	mov %ebx, %eax
327	pop %ebx
328	pop %ebp
329	ret