1#
2# Copyright (c) 1998 Robert Nordier
3# All rights reserved.
4#
5# Redistribution and use in source and binary forms are freely
6# permitted provided that the above copyright notice and this
7# paragraph and the following disclaimer are duplicated in all
8# such forms.
9#
10# This software is provided "AS IS" and without any express or
11# implied warranties, including, without limitation, the implied
12# warranties of merchantability and fitness for a particular
13# purpose.
14#
15
16# $Id: boot1.s,v 1.8 1999/01/13 23:30:07 rnordier Exp $
17
18 .set MEM_REL,0x700 # Relocation address
19 .set MEM_ARG,0x900 # Arguments
20 .set MEM_ORG,0x7c00 # Origin
21 .set MEM_BUF,0x8c00 # Load area
22 .set MEM_BTX,0x9000 # BTX start
23 .set MEM_JMP,0x9010 # BTX entry point
24 .set MEM_USR,0xa000 # Client start
--- 9 unchanged lines hidden (view full) ---
34 .globl xread
35
36start: jmp main # Start recognizably
37
38 .org 0x4,0x90
39
40# External read from disk
41
42xread: pushl %ss # Address
43 popl %ds # data
44xread.1: o16 # Starting
45 pushb $0x0 # absolute
46 pushl %ecx # block
47 pushl %eax # number
48 pushl %es # Address of
49 pushl %ebx # transfer buffer
50 xorl %eax,%eax # Number of
51 movb %dh,%al # blocks to
52 pushl %eax # transfer
53 pushb $0x10 # Size of packet
54 movl %esp,%ebp # Packet pointer
55 callwi(read) # Read from disk
56 leaw1r(0x10,_bp_,_sp) # Clear stack
57 lret # To far caller
58
59# Bootstrap
60
61main: cld # String ops inc
62 xorl %ecx,%ecx # Zero
63 movl %cx,%es # Address
64 movl %cx,%ds # data
--- 61 unchanged lines hidden (view full) ---
126 ret # To caller
127
128# Local read from disk
129
130nread: movwir(MEM_BUF,_bx) # Transfer buffer
131 movw1r(0x8,_si_,_ax) # Get
132 movw1r(0xa,_si_,_cx) # LBA
133 pushl %cs # Read from
134 callwi(xread.1) # disk
135 jnc return # If success
136 movwir(msg_read,_si) # Message
137
138# Error exit
139
140error: callwi(putstr) # Display message
141 movwir(prompt,_si) # Display
142 callwi(putstr) # prompt
--- 11 unchanged lines hidden (view full) ---
154 jne putstr.0 # No
155
156ereturn: movb $0x1,%ah # Invalid
157 stc # argument
158return: ret # To caller
159
160# Read from disk
161
162read: cs_ # LBA support
163 tstbim(0x80,MEM_REL+flags-start)# enabled?
164 jz read.1 # No
165 movwir(0x55aa,_bx) # Magic
166 pushl %edx # Save
167 movb $0x41,%ah # BIOS: Check
168 int $0x13 # extensions present
169 popl %edx # Restore
170 jc read.1 # If error
171 cmpwir(0xaa55,_bx) # Magic?
172 jne read.1 # No
173 testb $0x1,%cl # Packet interface?
174 jz read.1 # No
175 movl %ebp,%esi # Disk packet
176 movb $0x42,%ah # BIOS: Extended
177 int $0x13 # read
178 ret # To caller
179
180read.1: pushl %edx # Save
181 movb $0x8,%ah # BIOS: Get drive
182 int $0x13 # parameters
183 movb %dh,%ch # Max head number
184 popl %edx # Restore
185 jc return # If error
186 andb $0x3f,%cl # Sectors per track
187 jz ereturn # If zero
188 cli # Disable interrupts
--- 16 unchanged lines hidden (view full) ---
205 ja ereturn # No
206 xchgb %al,%ah # Set up cylinder
207 rorb $0x2,%al # number
208 orb %ch,%al # Merge
209 incl %eax # sector
210 xchgl %eax,%ecx # number
211 movb %bh,%dh # Head number
212 subb %ah,%al # Sectors this track
213 movb1r(0x2,_bp_,_ah) # Blocks to read
214 cmpb %ah,%al # To read
215 jb read.2 # this
216 movb %ah,%al # track
217read.2: movwir(0x5,_di) # Try count
218read.3: lesw1r(0x4,_bp_,_bx) # Transfer buffer
219 pushl %eax # Save
220 movb $0x2,%ah # BIOS: Read
221 int $0x13 # from disk
222 popl %ebx # Restore
223 jnc read.4 # If success
224 decl %edi # Retry?
225 jz read.6 # No
226 xorb %ah,%ah # BIOS: Reset
227 int $0x13 # disk system
228 xchgl %ebx,%eax # Block count
229 jmp read.3 # Continue
230read.4: movzbl %bl,%eax # Sectors read
231 addwr1(_ax,0x8,_bp_) # Adjust
232 jnc read.5 # LBA,
233 incw1(0xa,_bp_) # transfer
234read.5: shlb %bl # buffer
235 addbr1(_bl,0x5,_bp_) # pointer,
236 subbr1(_al,0x2,_bp_) # block count
237 ja read.1 # If not done
238read.6: ret # To caller
239
240# Messages
241
242msg_read: .asciz "Read"
243msg_part: .asciz "Boot"
244
245prompt: .asciz " error\r\n"
246
247flags: .byte FLAGS # Flags
248
249 .org PRT_OFF,0x90
250
251# Partition table
252
253 .fill 0x30,0x1,0x0
254part4: .byte 0x80, 0x00, 0x01, 0x00
255 .byte 0xa5, 0xff, 0xff, 0xff
256 .byte 0x00, 0x00, 0x00, 0x00
257 .byte 0x50, 0xc3, 0x00, 0x00
258
259 .word 0xaa55 # Magic number
2# Copyright (c) 1998 Robert Nordier
3# All rights reserved.
4#
5# Redistribution and use in source and binary forms are freely
6# permitted provided that the above copyright notice and this
7# paragraph and the following disclaimer are duplicated in all
8# such forms.
9#
10# This software is provided "AS IS" and without any express or
11# implied warranties, including, without limitation, the implied
12# warranties of merchantability and fitness for a particular
13# purpose.
14#
15
16# $Id: boot1.s,v 1.8 1999/01/13 23:30:07 rnordier Exp $
17
18 .set MEM_REL,0x700 # Relocation address
19 .set MEM_ARG,0x900 # Arguments
20 .set MEM_ORG,0x7c00 # Origin
21 .set MEM_BUF,0x8c00 # Load area
22 .set MEM_BTX,0x9000 # BTX start
23 .set MEM_JMP,0x9010 # BTX entry point
24 .set MEM_USR,0xa000 # Client start
--- 9 unchanged lines hidden (view full) ---
34 .globl xread
35
36start: jmp main # Start recognizably
37
38 .org 0x4,0x90
39
40# External read from disk
41
42xread: pushl %ss # Address
43 popl %ds # data
44xread.1: o16 # Starting
45 pushb $0x0 # absolute
46 pushl %ecx # block
47 pushl %eax # number
48 pushl %es # Address of
49 pushl %ebx # transfer buffer
50 xorl %eax,%eax # Number of
51 movb %dh,%al # blocks to
52 pushl %eax # transfer
53 pushb $0x10 # Size of packet
54 movl %esp,%ebp # Packet pointer
55 callwi(read) # Read from disk
56 leaw1r(0x10,_bp_,_sp) # Clear stack
57 lret # To far caller
58
59# Bootstrap
60
61main: cld # String ops inc
62 xorl %ecx,%ecx # Zero
63 movl %cx,%es # Address
64 movl %cx,%ds # data
--- 61 unchanged lines hidden (view full) ---
126 ret # To caller
127
128# Local read from disk
129
130nread: movwir(MEM_BUF,_bx) # Transfer buffer
131 movw1r(0x8,_si_,_ax) # Get
132 movw1r(0xa,_si_,_cx) # LBA
133 pushl %cs # Read from
134 callwi(xread.1) # disk
135 jnc return # If success
136 movwir(msg_read,_si) # Message
137
138# Error exit
139
140error: callwi(putstr) # Display message
141 movwir(prompt,_si) # Display
142 callwi(putstr) # prompt
--- 11 unchanged lines hidden (view full) ---
154 jne putstr.0 # No
155
156ereturn: movb $0x1,%ah # Invalid
157 stc # argument
158return: ret # To caller
159
160# Read from disk
161
162read: cs_ # LBA support
163 tstbim(0x80,MEM_REL+flags-start)# enabled?
164 jz read.1 # No
165 movwir(0x55aa,_bx) # Magic
166 pushl %edx # Save
167 movb $0x41,%ah # BIOS: Check
168 int $0x13 # extensions present
169 popl %edx # Restore
170 jc read.1 # If error
171 cmpwir(0xaa55,_bx) # Magic?
172 jne read.1 # No
173 testb $0x1,%cl # Packet interface?
174 jz read.1 # No
175 movl %ebp,%esi # Disk packet
176 movb $0x42,%ah # BIOS: Extended
177 int $0x13 # read
178 ret # To caller
179
180read.1: pushl %edx # Save
181 movb $0x8,%ah # BIOS: Get drive
182 int $0x13 # parameters
183 movb %dh,%ch # Max head number
184 popl %edx # Restore
185 jc return # If error
186 andb $0x3f,%cl # Sectors per track
187 jz ereturn # If zero
188 cli # Disable interrupts
--- 16 unchanged lines hidden (view full) ---
205 ja ereturn # No
206 xchgb %al,%ah # Set up cylinder
207 rorb $0x2,%al # number
208 orb %ch,%al # Merge
209 incl %eax # sector
210 xchgl %eax,%ecx # number
211 movb %bh,%dh # Head number
212 subb %ah,%al # Sectors this track
213 movb1r(0x2,_bp_,_ah) # Blocks to read
214 cmpb %ah,%al # To read
215 jb read.2 # this
216 movb %ah,%al # track
217read.2: movwir(0x5,_di) # Try count
218read.3: lesw1r(0x4,_bp_,_bx) # Transfer buffer
219 pushl %eax # Save
220 movb $0x2,%ah # BIOS: Read
221 int $0x13 # from disk
222 popl %ebx # Restore
223 jnc read.4 # If success
224 decl %edi # Retry?
225 jz read.6 # No
226 xorb %ah,%ah # BIOS: Reset
227 int $0x13 # disk system
228 xchgl %ebx,%eax # Block count
229 jmp read.3 # Continue
230read.4: movzbl %bl,%eax # Sectors read
231 addwr1(_ax,0x8,_bp_) # Adjust
232 jnc read.5 # LBA,
233 incw1(0xa,_bp_) # transfer
234read.5: shlb %bl # buffer
235 addbr1(_bl,0x5,_bp_) # pointer,
236 subbr1(_al,0x2,_bp_) # block count
237 ja read.1 # If not done
238read.6: ret # To caller
239
240# Messages
241
242msg_read: .asciz "Read"
243msg_part: .asciz "Boot"
244
245prompt: .asciz " error\r\n"
246
247flags: .byte FLAGS # Flags
248
249 .org PRT_OFF,0x90
250
251# Partition table
252
253 .fill 0x30,0x1,0x0
254part4: .byte 0x80, 0x00, 0x01, 0x00
255 .byte 0xa5, 0xff, 0xff, 0xff
256 .byte 0x00, 0x00, 0x00, 0x00
257 .byte 0x50, 0xc3, 0x00, 0x00
258
259 .word 0xaa55 # Magic number