[unix-history] / usr / src / sys.386bsd / i386 / stand / fdbootblk.c

/*-
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * William Jolitz.
 *
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 *	@(#)fdbootblk.c	7.2 (Berkeley) 5/4/91
 */

/*
 * fdbootblk.s:
 *	Written 10/6/90 by William F. Jolitz
 *	Initial block boot for AT/386 with typical stupid NEC controller
 *	Works only with 3.5 inch diskettes that have 16 or greater sectors/side
 *
 *	Goal is to read in sucessive 7.5Kbytes of bootstrap to
 *	execute.
 *
 *	No attempt is made to handle disk errors.
 */
/*#include "/sys/i386/isa/isa.h"
#include "/sys/i386/isa/fdreg.h"*/
#define	NOP	jmp 1f ; nop ; 1:
#define BIOSRELOC	0x7c00
#define	start	0x70400

	/* step 0 force descriptors to bottom of address space */

	.byte 0xfa,0xb8,0x30,0x00,0x8e,0xd0,0xbc,0x00,0x01 #ll fb

	xorl	%eax,%eax
	movl	%ax,%ds
	movl	%ax,%es

	/* step 1 load new descriptor table */

	.byte 0x2E,0x0F,1,0x16
	.word	BIOSRELOC+0x4a	#GDTptr
	# word aword cs lgdt GDTptr

	/* step 2 turn on protected mode */

	smsw	%ax
	orb	$1,%al
	lmsw	%ax
	jmp	1f
	nop

	/* step 3  reload segment descriptors */

 1:
	xorl	%eax,%eax
	movb	$0x10,%al
	movl	%ax,%ds
	movl	%ax,%es
	movl	%ax,%ss
	word
	ljmp	$0x8,$ BIOSRELOC+0x59	/* would be nice if .-RELOC+0x7c00 worked */

 /* Global Descriptor Table contains three descriptors:
  * 0x00: Null: not used
  * 0x08: Code: code segment starts at 0 and extents for 4 gigabytes
  * 0x10: Data: data segment starts at 0 and extends for 4 gigabytes
  *		(overlays code)
  */
GDT:
NullDesc:	.word	0,0,0,0	# null descriptor - not used
CodeDesc:	.word	0xFFFF	# limit at maximum: (bits 15:0)
	.byte	0,0,0	# base at 0: (bits 23:0)
	.byte	0x9f	# present/priv level 0/code/conforming/readable
	.byte	0xcf	# page granular/default 32-bit/limit(bits 19:16)
	.byte	0	# base at 0: (bits 31:24)
DataDesc:	.word	0xFFFF	# limit at maximum: (bits 15:0)
	.byte	0,0,0	# base at 0: (bits 23:0)
	.byte	0x93	# present/priv level 0/data/expand-up/writeable
	.byte	0xcf	# page granular/default 32-bit/limit(bits 19:16)
	.byte	0	# base at 0: (bits 31:24)

/* Global Descriptor Table pointer
 *  contains 6-byte pointer information for LGDT
 */
GDTptr:	.word	0x17	# limit to three 8 byte selectors(null,code,data)
	.long 	BIOSRELOC+0x32	# GDT -- arrgh, gas again!
readcmd: .byte 0xe6,0,0,0,0,2,18,0x1b,0xff

	/* step 4 relocate to final bootstrap address. */
reloc:
	movl	$ BIOSRELOC,%esi
	movl	$ RELOC,%edi
	movl	$512,%ecx
	rep
	movsb
	pushl	$dodisk
	ret

	/* step 5 load remaining 15 sectors off disk */
dodisk:
	movl	$0x70200,%edi
	xorl	%ebx,%ebx
	incb	%bl
	incb	%bl
	movb	$0x20,%al	# do a eoi
	outb	%al,$0x20

	NOP
	movb	$0x07,%al
	outb	%al,$0x21
	NOP
 8:
	movb	%bl,readcmd+4
	movl	%edi,%ecx

	/* Set read/write bytes */
	xorl	%edx,%edx
	movb	$0x0c,%dl	# outb(0xC,0x46); outb(0xB,0x46);
	movb	$0x46,%al
	outb	%al,%dx
	NOP
	decb	%dx
	outb	%al,%dx

	/* Send start address */
	movb	$0x04,%dl	# outb(0x4, addr);
	movb	%cl,%al
	outb	%al,%dx
	NOP
	movb	%ch,%al		# outb(0x4, addr>>8);
	outb	%al,%dx
	NOP
	rorl	$8,%ecx		# outb(0x81, addr>>16);
	movb	%ch,%al
	outb	%al,$0x81
	NOP

	/* Send count */
	movb	$0x05,%dl	# outb(0x5, 0);
	xorl	%eax,%eax
	outb	%al,%dx
	NOP
	movb	$2,%al		# outb(0x5,2);
	outb	%al,%dx
	NOP

	/* set channel 2 */
	# movb	$2,%al		# outb(0x0A,2);
	outb	%al,$0x0A
	NOP

	/* issue read command to fdc */
	movw	$0x3f4,%dx
	movl	$readcmd,%esi
	xorl	%ecx,%ecx
	movb	$9,%cl

 2:	inb	%dx,%al
	NOP
	testb	$0x80,%al
	jz 2b

	incb	%dx
	movl	(%esi),%al
	outb	%al,%dx
	NOP
	incl	%esi
	decb	%dx
	loop	 2b

	/* watch the icu looking for an interrupt signalling completion */
	xorl	%edx,%edx
	movb	$0x20,%dl
 2:	movb	$0xc,%al
	outb	%al,%dx
	NOP
	inb	%dx,%al
	NOP
	andb	$0x7f,%al
	cmpb	$6,%al
	jne	2b
	movb	$0x20,%al	# do a eoi
	outb	%al,%dx
	NOP

	movl	$0x3f4,%edx
	xorl	%ecx,%ecx
	movb	$7,%cl
 2:	inb	%dx,%al
	NOP
	andb	$0xC0,%al
	cmpb	$0xc0,%al
	jne	2b
	incb	%dx
	inb	%dx,%al
	decb	%dx
	loop	2b

	/* extract the status bytes after the read. must we do this? */
	addw	$0x200,%edi	# next addr to load to
	incb	%bl
	cmpb	$15,%bl
	jle	8b
	
	/* for clever bootstrap, dig out boot unit and cylinder */
	pushl	$0
	pushl	$0
	
	/* fd controller is major device 2 */
	pushl	$2	/* dev */

	/* sorry, no flags at this point! */

	pushl $	start
	ret	/* main (dev, unit, off) */

ebootblkcode:

	/* remaining space usable for a disk label */
	
	.space	510-310		/* would be nice if .space 512-2-. worked */
	.word	0xaa55		/* signature -- used by BIOS ROM */

ebootblk: 			/* MUST BE EXACTLY 0x200 BIG FOR SURE */
Commit	Line	Data
b13ce198 WJ	1	/*-
	2	* Copyright (c) 1990 The Regents of the University of California.
	3	* All rights reserved.
	4	*
	5	* This code is derived from software contributed to Berkeley by
	6	* William Jolitz.
	7	*
	8	* Redistribution and use in source and binary forms, with or without
	9	* modification, are permitted provided that the following conditions
	10	* are met:
	11	* 1. Redistributions of source code must retain the above copyright
	12	* notice, this list of conditions and the following disclaimer.
	13	* 2. Redistributions in binary form must reproduce the above copyright
	14	* notice, this list of conditions and the following disclaimer in the
	15	* documentation and/or other materials provided with the distribution.
	16	* 3. All advertising materials mentioning features or use of this software
	17	* must display the following acknowledgement:
	18	* This product includes software developed by the University of
	19	* California, Berkeley and its contributors.
	20	* 4. Neither the name of the University nor the names of its contributors
	21	* may be used to endorse or promote products derived from this software
	22	* without specific prior written permission.
	23	*
	24	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	25	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	26	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	27	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	28	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	29	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	30	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	31	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	32	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	33	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	34	* SUCH DAMAGE.
	35	*
	36	* @(#)fdbootblk.c 7.2 (Berkeley) 5/4/91
	37	*/
	38
	39	/*
	40	* fdbootblk.s:
	41	* Written 10/6/90 by William F. Jolitz
	42	* Initial block boot for AT/386 with typical stupid NEC controller
	43	* Works only with 3.5 inch diskettes that have 16 or greater sectors/side
	44	*
	45	* Goal is to read in sucessive 7.5Kbytes of bootstrap to
	46	* execute.
	47	*
	48	* No attempt is made to handle disk errors.
	49	*/
	50	/*#include "/sys/i386/isa/isa.h"
	51	#include "/sys/i386/isa/fdreg.h"*/
	52	#define NOP jmp 1f ; nop ; 1:
	53	#define BIOSRELOC 0x7c00
	54	#define start 0x70400
	55
	56	/* step 0 force descriptors to bottom of address space */
	57
	58	.byte 0xfa,0xb8,0x30,0x00,0x8e,0xd0,0xbc,0x00,0x01 #ll fb
	59
	60	xorl %eax,%eax
	61	movl %ax,%ds
	62	movl %ax,%es
	63
	64	/* step 1 load new descriptor table */
65
66	.byte 0x2E,0x0F,1,0x16
67	.word BIOSRELOC+0x4a #GDTptr
68	# word aword cs lgdt GDTptr
69
70	/* step 2 turn on protected mode */
71
72	smsw %ax
73	orb $1,%al
74	lmsw %ax
75	jmp 1f
76	nop
77
78	/* step 3 reload segment descriptors */
79
80	1:
81	xorl %eax,%eax
82	movb $0x10,%al
83	movl %ax,%ds
84	movl %ax,%es
85	movl %ax,%ss
86	word
87	ljmp $0x8,$ BIOSRELOC+0x59 /* would be nice if .-RELOC+0x7c00 worked */
88
89	/* Global Descriptor Table contains three descriptors:
90	* 0x00: Null: not used
91	* 0x08: Code: code segment starts at 0 and extents for 4 gigabytes
92	* 0x10: Data: data segment starts at 0 and extends for 4 gigabytes
93	* (overlays code)
94	*/
95	GDT:
96	NullDesc: .word 0,0,0,0 # null descriptor - not used
97	CodeDesc: .word 0xFFFF # limit at maximum: (bits 15:0)
98	.byte 0,0,0 # base at 0: (bits 23:0)
99	.byte 0x9f # present/priv level 0/code/conforming/readable
100	.byte 0xcf # page granular/default 32-bit/limit(bits 19:16)
101	.byte 0 # base at 0: (bits 31:24)
102	DataDesc: .word 0xFFFF # limit at maximum: (bits 15:0)
103	.byte 0,0,0 # base at 0: (bits 23:0)
104	.byte 0x93 # present/priv level 0/data/expand-up/writeable
105	.byte 0xcf # page granular/default 32-bit/limit(bits 19:16)
106	.byte 0 # base at 0: (bits 31:24)
107
108	/* Global Descriptor Table pointer
109	* contains 6-byte pointer information for LGDT
110	*/
111	GDTptr: .word 0x17 # limit to three 8 byte selectors(null,code,data)
112	.long BIOSRELOC+0x32 # GDT -- arrgh, gas again!
113	readcmd: .byte 0xe6,0,0,0,0,2,18,0x1b,0xff
114
115	/* step 4 relocate to final bootstrap address. */
116	reloc:
117	movl $ BIOSRELOC,%esi
118	movl $ RELOC,%edi
119	movl $512,%ecx
120	rep
121	movsb
122	pushl $dodisk
123	ret
124
125	/* step 5 load remaining 15 sectors off disk */
126	dodisk:
127	movl $0x70200,%edi
128	xorl %ebx,%ebx
129	incb %bl
130	incb %bl
131	movb $0x20,%al # do a eoi
132	outb %al,$0x20
133
134	NOP
135	movb $0x07,%al
136	outb %al,$0x21
137	NOP
138	8:
139	movb %bl,readcmd+4
140	movl %edi,%ecx
141
142	/* Set read/write bytes */
143	xorl %edx,%edx
144	movb $0x0c,%dl # outb(0xC,0x46); outb(0xB,0x46);
145	movb $0x46,%al
146	outb %al,%dx
147	NOP
148	decb %dx
149	outb %al,%dx
150
151	/* Send start address */
152	movb $0x04,%dl # outb(0x4, addr);
153	movb %cl,%al
154	outb %al,%dx
155	NOP
156	movb %ch,%al # outb(0x4, addr>>8);
157	outb %al,%dx
158	NOP
159	rorl $8,%ecx # outb(0x81, addr>>16);
160	movb %ch,%al
161	outb %al,$0x81
162	NOP
163
164	/* Send count */
165	movb $0x05,%dl # outb(0x5, 0);
166	xorl %eax,%eax
167	outb %al,%dx
168	NOP
169	movb $2,%al # outb(0x5,2);
170	outb %al,%dx
171	NOP
172
173	/* set channel 2 */
174	# movb $2,%al # outb(0x0A,2);
175	outb %al,$0x0A
176	NOP
177
178	/* issue read command to fdc */
179	movw $0x3f4,%dx
180	movl $readcmd,%esi
181	xorl %ecx,%ecx
182	movb $9,%cl
183
184	2: inb %dx,%al
185	NOP
186	testb $0x80,%al
187	jz 2b
188
189	incb %dx
190	movl (%esi),%al
191	outb %al,%dx
192	NOP
193	incl %esi
194	decb %dx
195	loop 2b
196
197	/* watch the icu looking for an interrupt signalling completion */
198	xorl %edx,%edx
199	movb $0x20,%dl
200	2: movb $0xc,%al
201	outb %al,%dx
202	NOP
203	inb %dx,%al
204	NOP
205	andb $0x7f,%al
206	cmpb $6,%al
207	jne 2b
208	movb $0x20,%al # do a eoi
209	outb %al,%dx
210	NOP
211
212	movl $0x3f4,%edx
213	xorl %ecx,%ecx
214	movb $7,%cl
215	2: inb %dx,%al
216	NOP
217	andb $0xC0,%al
218	cmpb $0xc0,%al
219	jne 2b
220	incb %dx
221	inb %dx,%al
222	decb %dx
223	loop 2b
224
225	/* extract the status bytes after the read. must we do this? */
226	addw $0x200,%edi # next addr to load to
227	incb %bl
228	cmpb $15,%bl
229	jle 8b
230
231	/* for clever bootstrap, dig out boot unit and cylinder */
232	pushl $0
233	pushl $0
234
235	/* fd controller is major device 2 */
236	pushl $2 /* dev */
237
238	/* sorry, no flags at this point! */
239
240	pushl $ start
241	ret /* main (dev, unit, off) */
242
243	ebootblkcode:
244
245	/* remaining space usable for a disk label */
246
247	.space 510-310 /* would be nice if .space 512-2-. worked */
248	.word 0xaa55 /* signature -- used by BIOS ROM */
249
250	ebootblk: /* MUST BE EXACTLY 0x200 BIG FOR SURE */