| cdboot.S (58713) | cdboot.S (60821) |
|---|---|
| 1# 2# Copyright (c) 2000 John Baldwin 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 | 1# 2# Copyright (c) 2000 John Baldwin 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# $FreeBSD: head/sys/boot/i386/cdboot/cdboot.s 58713 2000-03-28 01:19:53Z jhb $ | 16# $FreeBSD: head/sys/boot/i386/cdboot/cdboot.s 60821 2000-05-23 12:18:49Z jhb $ |
| 17 18# 19# This simple program is a preloader for the normal boot3 loader. It is simply 20# prepended to the beginning of a fully built and btxld'd loader. It then 21# copies the loader to the address boot2 normally loads it, emulates the 22# boot[12] environment (protected mode, a bootinfo struct, etc.), and then jumps 23# to the start of btxldr to start the boot process. This method allows a stock 24# /boot/loader to be used w/o having to fully rewrite boot[12] to handle the --- 51 unchanged lines hidden (view full) --- 76 xorw %ax, %ax # zero %ax 77 movw %ax, %ss # setup the 78 movw $start, %sp # stack 79 pushw %dx # save the BIOS boot device in 80 # %dl for later 81 movw %ax, %ds # setup the 82 movw %ax, %es # data segments 83 movw $welcome_msg, %si # %ds:(%si) -> welcome message | 17 18# 19# This simple program is a preloader for the normal boot3 loader. It is simply 20# prepended to the beginning of a fully built and btxld'd loader. It then 21# copies the loader to the address boot2 normally loads it, emulates the 22# boot[12] environment (protected mode, a bootinfo struct, etc.), and then jumps 23# to the start of btxldr to start the boot process. This method allows a stock 24# /boot/loader to be used w/o having to fully rewrite boot[12] to handle the --- 51 unchanged lines hidden (view full) --- 76 xorw %ax, %ax # zero %ax 77 movw %ax, %ss # setup the 78 movw $start, %sp # stack 79 pushw %dx # save the BIOS boot device in 80 # %dl for later 81 movw %ax, %ds # setup the 82 movw %ax, %es # data segments 83 movw $welcome_msg, %si # %ds:(%si) -> welcome message |
| 84 call putstr # display the welcome message | 84 callw putstr # display the welcome message |
| 85# 86# Setup the arguments that the loader is expecting from boot[12] 87# 88 movw $bootinfo_msg, %si # %ds:(%si) -> boot args message | 85# 86# Setup the arguments that the loader is expecting from boot[12] 87# 88 movw $bootinfo_msg, %si # %ds:(%si) -> boot args message |
| 89 call putstr # display the message 90 movl $MEM_ARG, %ebx # %ds:(%ebx) -> boot args | 89 callw putstr # display the message 90 movl $MEM_ARG, %bx # %ds:(%bx) -> boot args |
| 91 movw %bx, %di # %es:(%di) -> boot args 92 xorl %eax, %eax # zero %eax 93 movw $(MEM_ARG_SIZE/4), %cx # Size of arguments in 32-bit 94 # dwords 95 rep # Clear the arguments 96 stosl # to zero 97 popw %dx # restore BIOS boot device | 91 movw %bx, %di # %es:(%di) -> boot args 92 xorl %eax, %eax # zero %eax 93 movw $(MEM_ARG_SIZE/4), %cx # Size of arguments in 32-bit 94 # dwords 95 rep # Clear the arguments 96 stosl # to zero 97 popw %dx # restore BIOS boot device |
| 98 movb %dl, 0x4(%ebx) # set kargs->bootdev 99 orb $KARGS_FLAGS_CD, 0x8(%ebx) # kargs->bootflags |= | 98 movb %dl, 0x4(%bx) # set kargs->bootdev 99 orb $KARGS_FLAGS_CD, 0x8(%bx) # kargs->bootflags |= |
| 100 # KARGS_FLAGS_CD 101# 102# Turn on the A20 address line 103# | 100 # KARGS_FLAGS_CD 101# 102# Turn on the A20 address line 103# |
| 104 call seta20 # Turn A20 on | 104 callw seta20 # Turn A20 on |
| 105# 106# Relocate the loader and BTX using a very lazy protected mode 107# 108 movw $relocate_msg, %si # Display the | 105# 106# Relocate the loader and BTX using a very lazy protected mode 107# 108 movw $relocate_msg, %si # Display the |
| 109 call putstr # relocation message | 109 callw putstr # relocation message |
| 110 movl end+AOUT_ENTRY, %edi # %edi is the destination 111 movl $(end+AOUT_HEADER), %esi # %esi is 112 # the start of the text 113 # segment 114 movl end+AOUT_TEXT, %ecx # %ecx = length of the text 115 # segment 116 lgdt gdtdesc # setup our own gdt 117 cli # turn off interrupts 118 movl %cr0, %eax # Turn on 119 orb $0x1, %al # protected 120 movl %eax, %cr0 # mode | 110 movl end+AOUT_ENTRY, %edi # %edi is the destination 111 movl $(end+AOUT_HEADER), %esi # %esi is 112 # the start of the text 113 # segment 114 movl end+AOUT_TEXT, %ecx # %ecx = length of the text 115 # segment 116 lgdt gdtdesc # setup our own gdt 117 cli # turn off interrupts 118 movl %cr0, %eax # Turn on 119 orb $0x1, %al # protected 120 movl %eax, %cr0 # mode |
| 121 .byte 0xea # long jump to 122 .word pm_start # clear the instruction 123 .word SEL_SCODE # pre-fetch queue | 121 ljmp $SEL_SCODE,$pm_start # long jump to clear the 122 # instruction pre-fetch queue |
| 124 .code32 125pm_start: movw $SEL_SDATA, %ax # Initialize 126 movw %ax, %ds # %ds and 127 movw %ax, %es # %es to a flat selector 128 rep # Relocate the 129 movsb # text segment 130 addl $(MEM_PAGE_SIZE - 1), %edi # pad %edi out to a new page 131 andl $~(MEM_PAGE_SIZE - 1), %edi # for the data segment --- 15 unchanged lines hidden (view full) --- 147 ljmp $SEL_SCODE16,$pm_16 # Jump to 16-bit PM 148 .code16 149pm_16: movw $SEL_RDATA, %ax # Initialize 150 movw %ax, %ds # %ds and 151 movw %ax, %es # %es to a real mode selector 152 movl %cr0, %eax # Turn off 153 andb $~0x1, %al # protected 154 movl %eax, %cr0 # mode | 123 .code32 124pm_start: movw $SEL_SDATA, %ax # Initialize 125 movw %ax, %ds # %ds and 126 movw %ax, %es # %es to a flat selector 127 rep # Relocate the 128 movsb # text segment 129 addl $(MEM_PAGE_SIZE - 1), %edi # pad %edi out to a new page 130 andl $~(MEM_PAGE_SIZE - 1), %edi # for the data segment --- 15 unchanged lines hidden (view full) --- 146 ljmp $SEL_SCODE16,$pm_16 # Jump to 16-bit PM 147 .code16 148pm_16: movw $SEL_RDATA, %ax # Initialize 149 movw %ax, %ds # %ds and 150 movw %ax, %es # %es to a real mode selector 151 movl %cr0, %eax # Turn off 152 andb $~0x1, %al # protected 153 movl %eax, %cr0 # mode |
| 155 .byte 0xea # Long jump to 156 .word pm_end # clear the instruction 157 .word 0x0 # pre-fetch | 154 ljmp $0,$pm_end # Long jump to clear the 155 # instruction pre-fetch queue |
| 158pm_end: sti # Turn interrupts back on now 159# 160# Copy the BTX client to MEM_BTX_CLIENT 161# 162 xorw %ax, %ax # zero %ax and set 163 movw %ax, %ds # %ds and %es 164 movw %ax, %es # to segment 0 165 movw $MEM_BTX_CLIENT, %di # Prepare to relocate --- 14 unchanged lines hidden (view full) --- 180# 181 movl end+AOUT_ENTRY, %eax # load the entry point 182 stosl # add it to the end of the 183 # arguments 184# 185# Now we just start up BTX and let it do the rest 186# 187 movw $jump_message, %si # Display the | 156pm_end: sti # Turn interrupts back on now 157# 158# Copy the BTX client to MEM_BTX_CLIENT 159# 160 xorw %ax, %ax # zero %ax and set 161 movw %ax, %ds # %ds and %es 162 movw %ax, %es # to segment 0 163 movw $MEM_BTX_CLIENT, %di # Prepare to relocate --- 14 unchanged lines hidden (view full) --- 178# 179 movl end+AOUT_ENTRY, %eax # load the entry point 180 stosl # add it to the end of the 181 # arguments 182# 183# Now we just start up BTX and let it do the rest 184# 185 movw $jump_message, %si # Display the |
| 188 call putstr # jump message 189 .byte 0xea # Jump to 190 .word MEM_BTX_ENTRY # BTX entry 191 .word 0x0 # point | 186 callw putstr # jump message 187 ljmp $0,$MEM_BTX_ENTRY # Jump to the BTX entry point |
| 192 193# 194# Display a null-terminated string 195# 196putstr: lodsb # load %al from %ds:(%si) 197 testb %al,%al # stop at null 198 jnz putc # if the char != null, output it | 188 189# 190# Display a null-terminated string 191# 192putstr: lodsb # load %al from %ds:(%si) 193 testb %al,%al # stop at null 194 jnz putc # if the char != null, output it |
| 199 ret # return when null is hit | 195 retw # return when null is hit |
| 200putc: movw $0x7,%bx # attribute for output 201 movb $0xe,%ah # BIOS: put_char 202 int $0x10 # call BIOS, print char in %al 203 jmp putstr # keep looping 204 205# 206# Enable A20 207# --- 4 unchanged lines hidden (view full) --- 212 movb $0xd1,%al # Command: Write 213 outb %al,$0x64 # output port 214seta20.2: inb $0x64,%al # Get status 215 testb $0x2,%al # Busy? 216 jnz seta20.2 # Yes 217 movb $0xdf,%al # Enable 218 outb %al,$0x60 # A20 219 sti # Enable interrupts | 196putc: movw $0x7,%bx # attribute for output 197 movb $0xe,%ah # BIOS: put_char 198 int $0x10 # call BIOS, print char in %al 199 jmp putstr # keep looping 200 201# 202# Enable A20 203# --- 4 unchanged lines hidden (view full) --- 208 movb $0xd1,%al # Command: Write 209 outb %al,$0x64 # output port 210seta20.2: inb $0x64,%al # Get status 211 testb $0x2,%al # Busy? 212 jnz seta20.2 # Yes 213 movb $0xdf,%al # Enable 214 outb %al,$0x60 # A20 215 sti # Enable interrupts |
| 220 ret # To caller | 216 retw # To caller |
| 221 222# 223# BTX client to start btxldr 224# 225 .code32 226btx_client: movl $(MEM_ARG_BTX-MEM_BTX_CLIENT+MEM_ARG_SIZE-4), %esi 227 # %ds:(%esi) -> end 228 # of boot[12] args --- 36 unchanged lines hidden --- | 217 218# 219# BTX client to start btxldr 220# 221 .code32 222btx_client: movl $(MEM_ARG_BTX-MEM_BTX_CLIENT+MEM_ARG_SIZE-4), %esi 223 # %ds:(%esi) -> end 224 # of boot[12] args --- 36 unchanged lines hidden --- |