1# Copyright (c) KATO Takenori, 1999, 2000.
2#
3# All rights reserved. Unpublished rights reserved under the copyright
4# laws of Japan.
5#
6# Redistribution and use in source and binary forms, with or without
7# modification, are permitted provided that the following conditions
8# are met:
9#
10# 1. Redistributions of source code must retain the above copyright
11# notice, this list of conditions and the following disclaimer as
12# the first lines of this file unmodified.
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#
17# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27#
| 1# Copyright (c) KATO Takenori, 1999, 2000.
2#
3# All rights reserved. Unpublished rights reserved under the copyright
4# laws of Japan.
5#
6# Redistribution and use in source and binary forms, with or without
7# modification, are permitted provided that the following conditions
8# are met:
9#
10# 1. Redistributions of source code must retain the above copyright
11# notice, this list of conditions and the following disclaimer as
12# the first lines of this file unmodified.
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#
17# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27#
|
28# $FreeBSD: head/sys/boot/pc98/boot0.5/boot.s 64190 2000-08-03 13:01:45Z kato $
| 28# $FreeBSD: head/sys/boot/pc98/boot0.5/boot.s 167657 2007-03-17 05:30:03Z kato $
|
29#
30
31 .code16
32
33 .text
34 .global boot
35#
36# Read bootstrap program and jump to it.
37#
38boot:
39 # Step 1: Save parameters
40 movw curdevice, %si
41 movb daua(%si), %al
42 movb %al, b_daua
43 shlw %si
44 movw secsize(%si), %ax
45 movw %ax, b_secsize
46
47 movw curpartition, %si
48 movb partnum(%si), %al # %al = real partition number
49 xorb %ah, %ah
50 movw %ax, b_partn # save real parttion number
51 movb $5, %cl
52 shlw %cl, %si # %si = offset to parttable
53 addw $4, %si
54 movb parttable(%si), %al # IPLS
55 movb %al, b_sector
56 incw %si
57 movb parttable(%si), %al # IPLH
58 movb %al, b_head
59 incw %si # IPLC
60 movw parttable(%si), %ax
61 movw %ax, b_cylinder
62
| 29#
30
31 .code16
32
33 .text
34 .global boot
35#
36# Read bootstrap program and jump to it.
37#
38boot:
39 # Step 1: Save parameters
40 movw curdevice, %si
41 movb daua(%si), %al
42 movb %al, b_daua
43 shlw %si
44 movw secsize(%si), %ax
45 movw %ax, b_secsize
46
47 movw curpartition, %si
48 movb partnum(%si), %al # %al = real partition number
49 xorb %ah, %ah
50 movw %ax, b_partn # save real parttion number
51 movb $5, %cl
52 shlw %cl, %si # %si = offset to parttable
53 addw $4, %si
54 movb parttable(%si), %al # IPLS
55 movb %al, b_sector
56 incw %si
57 movb parttable(%si), %al # IPLH
58 movb %al, b_head
59 incw %si # IPLC
60 movw parttable(%si), %ax
61 movw %ax, b_cylinder
62
|
63 # Step 2: Calculate egment address of bootstrap routine
| 63 # Step 2: Calculate the segment address of the bootstrap routine
|
64 movw $0x1d00, %ax
65 movw b_secsize, %cx
66 shrw %cx
67 shrw %cx
68 subw %cx, %ax
69 subw $0x100, %ax
70 movw %ax, b_bootseg
71
72 # Step 3: Read bootstrap code
73 movb $6, %ah
74 movb b_daua, %al
75 movw b_secsize, %bx
76 shlw %bx # 2 sectors
77 movw b_cylinder, %cx
78 movb b_head, %dh
79 movb b_sector, %dl
80 movw b_bootseg, %es
81 xorw %bp, %bp
82 int $0x1b
83 jc boot_error
84
85 # Step 4: Set DA/UA into BIOS work area
86 xorw %ax, %ax
87 movw %ax, %es
88 movw $0x584, %bx # DISK_BOOT
89 movb b_daua, %dl
90 call write_biosparam
91
92 call sc_clean
93 # Step 5: Set registers
94 # %ah: 00
95 # %al: DA/UA
96 # %bx: Sector size * 2
97 # %cx: cylinder number of boot partition
98 # %si: pointer to partition table
99 movw b_partn, %ax
100 movb $5, %cl
101 shl %cl, %ax # %ax = partition number * 32
102 addw b_secsize, %ax
103 movw %ax, %si # %si = pointer to partition table
104 movw b_cylinder, %cx # %cx = cylinder
105 movb b_head, %dh # %dh = head
106 movb b_sector, %dl # %dl = sector
107 movw b_bootseg, %es # %es = boot segment
108 movb b_daua, %al # %al = DA/UA
109 movw b_secsize, %bx
110 shlw %bx # %bx = sector size * 2
111 cli
112 movw %cs:iniss, %ss # Restore stack pointer
113 movw %cs:inisp, %sp
114 push %es # Boot segment
115 xorw %bp, %bp
116 push %bp # 0
117 movw %ax, %di # Save %ax
118 xorw %ax, %ax
119 movw %ax, %ds # %ds = 0
120 movw %di, %ax # Restore %ax
121 xorb %ah, %ah # %ah = 0
122 xorw %di, %di # %di = 0
123 sti
124
125 # Jump to bootstrap code
126 lret
127 # NOTREACHED
128
129boot_error:
130 ret
131
132#
133# Try to boot from default partition.
134#
135 .global trydefault
136trydefault:
137 movw ndevice, %cx
138 xorw %si, %si
139trydefault_loop:
140 movw %si, curdevice
141 push %cx
142 push %si
143 call read_ipl
144 pop %si
145 pop %cx
146 cmpb $0x80, defpartflag
147 jne nodefpart
148 # Default partition is defined.
149 push %cx
150 movw npartition, %cx
151srch_part:
152 movw %cx, %bx
153 decw %bx
154 movb defpartnum, %al # %al = real partition number
155 cmpb partnum(%bx), %al
156 jne not_match
157 movw %bx, curpartition # Store partition number
158 call boot
159not_match:
160 loop srch_part
161 pop %cx
162nodefpart:
163 incw %si
164 loop trydefault_loop
165 ret
166
167 .data
168b_daua: .byte 0 # DA/UA
169b_head: .byte 0 # SYSH
170b_sector: .byte 0 # SYSS
171b_cylinder: .word 0 # SYSC
172b_bootseg: .word 0
173b_secsize: .word 0
174b_partn: .word 0 # Real partition number
| 64 movw $0x1d00, %ax
65 movw b_secsize, %cx
66 shrw %cx
67 shrw %cx
68 subw %cx, %ax
69 subw $0x100, %ax
70 movw %ax, b_bootseg
71
72 # Step 3: Read bootstrap code
73 movb $6, %ah
74 movb b_daua, %al
75 movw b_secsize, %bx
76 shlw %bx # 2 sectors
77 movw b_cylinder, %cx
78 movb b_head, %dh
79 movb b_sector, %dl
80 movw b_bootseg, %es
81 xorw %bp, %bp
82 int $0x1b
83 jc boot_error
84
85 # Step 4: Set DA/UA into BIOS work area
86 xorw %ax, %ax
87 movw %ax, %es
88 movw $0x584, %bx # DISK_BOOT
89 movb b_daua, %dl
90 call write_biosparam
91
92 call sc_clean
93 # Step 5: Set registers
94 # %ah: 00
95 # %al: DA/UA
96 # %bx: Sector size * 2
97 # %cx: cylinder number of boot partition
98 # %si: pointer to partition table
99 movw b_partn, %ax
100 movb $5, %cl
101 shl %cl, %ax # %ax = partition number * 32
102 addw b_secsize, %ax
103 movw %ax, %si # %si = pointer to partition table
104 movw b_cylinder, %cx # %cx = cylinder
105 movb b_head, %dh # %dh = head
106 movb b_sector, %dl # %dl = sector
107 movw b_bootseg, %es # %es = boot segment
108 movb b_daua, %al # %al = DA/UA
109 movw b_secsize, %bx
110 shlw %bx # %bx = sector size * 2
111 cli
112 movw %cs:iniss, %ss # Restore stack pointer
113 movw %cs:inisp, %sp
114 push %es # Boot segment
115 xorw %bp, %bp
116 push %bp # 0
117 movw %ax, %di # Save %ax
118 xorw %ax, %ax
119 movw %ax, %ds # %ds = 0
120 movw %di, %ax # Restore %ax
121 xorb %ah, %ah # %ah = 0
122 xorw %di, %di # %di = 0
123 sti
124
125 # Jump to bootstrap code
126 lret
127 # NOTREACHED
128
129boot_error:
130 ret
131
132#
133# Try to boot from default partition.
134#
135 .global trydefault
136trydefault:
137 movw ndevice, %cx
138 xorw %si, %si
139trydefault_loop:
140 movw %si, curdevice
141 push %cx
142 push %si
143 call read_ipl
144 pop %si
145 pop %cx
146 cmpb $0x80, defpartflag
147 jne nodefpart
148 # Default partition is defined.
149 push %cx
150 movw npartition, %cx
151srch_part:
152 movw %cx, %bx
153 decw %bx
154 movb defpartnum, %al # %al = real partition number
155 cmpb partnum(%bx), %al
156 jne not_match
157 movw %bx, curpartition # Store partition number
158 call boot
159not_match:
160 loop srch_part
161 pop %cx
162nodefpart:
163 incw %si
164 loop trydefault_loop
165 ret
166
167 .data
168b_daua: .byte 0 # DA/UA
169b_head: .byte 0 # SYSH
170b_sector: .byte 0 # SYSS
171b_cylinder: .word 0 # SYSC
172b_bootseg: .word 0
173b_secsize: .word 0
174b_partn: .word 0 # Real partition number
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