15c15
< * $FreeBSD: head/sys/boot/i386/pxeldr/pxeldr.S 128716 2004-04-28 14:31:44Z ru $
---
> * $FreeBSD: head/sys/boot/i386/pxeldr/pxeldr.S 129240 2004-05-14 20:29:30Z ru $
22c22
< * boot[12] environment (protected mode, a bootinfo struct, etc.) and then jumps
---
> * boot[12] environment (protected mode, a bootinfo struct, etc.), and then jumps
31,40c31,40
< .set MEM_PAGE_SIZE,0x1000 // memory page size, 4k
< .set MEM_ARG,0x900 // Arguments at start
< .set MEM_ARG_BTX,0xa100 // Where we move them to so the
< // BTX client can see them
< .set MEM_ARG_SIZE,0x18 // Size of the arguments
< .set MEM_BTX_ADDRESS,0x9000 // where BTX lives
< .set MEM_BTX_ENTRY,0x9010 // where BTX starts to execute
< .set MEM_BTX_OFFSET,MEM_PAGE_SIZE // offset of BTX in the loader
< .set MEM_BTX_CLIENT,0xa000 // where BTX clients live
< .set MEM_BIOS_KEYBOARD,0x496 // BDA byte with keyboard bit
---
> .set MEM_PAGE_SIZE,0x1000 # memory page size, 4k
> .set MEM_ARG,0x900 # Arguments at start
> .set MEM_ARG_BTX,0xa100 # Where we move them to so the
> # BTX client can see them
> .set MEM_ARG_SIZE,0x18 # Size of the arguments
> .set MEM_BTX_ADDRESS,0x9000 # where BTX lives
> .set MEM_BTX_ENTRY,0x9010 # where BTX starts to execute
> .set MEM_BTX_OFFSET,MEM_PAGE_SIZE # offset of BTX in the loader
> .set MEM_BTX_CLIENT,0xa000 # where BTX clients live
> .set MEM_BIOS_KEYBOARD,0x496 # BDA byte with keyboard bit
44,49c44,49
< .set AOUT_TEXT,0x04 // text segment size
< .set AOUT_DATA,0x08 // data segment size
< .set AOUT_BSS,0x0c // zero'd BSS size
< .set AOUT_SYMBOLS,0x10 // symbol table
< .set AOUT_ENTRY,0x14 // entry point
< .set AOUT_HEADER,MEM_PAGE_SIZE // size of the a.out header
---
> .set AOUT_TEXT,0x04 # text segment size
> .set AOUT_DATA,0x08 # data segment size
> .set AOUT_BSS,0x0c # zero'd BSS size
> .set AOUT_SYMBOLS,0x10 # symbol table
> .set AOUT_ENTRY,0x14 # entry point
> .set AOUT_HEADER,MEM_PAGE_SIZE # size of the a.out header
53,54c53,54
< .set KARGS_FLAGS_PXE,0x2 // flag to indicate booting from
< // PXE loader
---
> .set KARGS_FLAGS_PXE,0x2 # flag to indicate booting from
> # PXE loader
58c58
< .set RB_SERIAL,0x1000 // serial console
---
> .set RB_SERIAL,0x1000 # serial console
62,65c62,65
< .set SEL_SDATA,0x8 // Supervisor data
< .set SEL_RDATA,0x10 // Real mode data
< .set SEL_SCODE,0x18 // PM-32 code
< .set SEL_SCODE16,0x20 // PM-16 code
---
> .set SEL_SDATA,0x8 # Supervisor data
> .set SEL_RDATA,0x10 # Real mode data
> .set SEL_SCODE,0x18 # PM-32 code
> .set SEL_SCODE16,0x20 # PM-16 code
69c69
< .set INT_SYS,0x30 // BTX syscall interrupt
---
> .set INT_SYS,0x30 # BTX syscall interrupt
84,97c84,97
< start: cld // string ops inc
< xorw %ax, %ax // zero %ax
< movw %ax, %ss // setup the
< movw $start, %sp // stack
< movw %es, %cx // save PXENV+ segment
< movw %ax, %ds // setup the
< movw %ax, %es // data segments
< andl $0xffff, %ecx // clear upper words
< andl $0xffff, %ebx // of %ebx and %ecx
< shll $4, %ecx // calculate the offset of
< addl %ebx, %ecx // the PXENV+ struct and
< pushl %ecx // save it on the stack
< movw $welcome_msg, %si // %ds:(%si) -> welcome message
< callw putstr // display the welcome message
---
> start: cld # string ops inc
> xorw %ax, %ax # zero %ax
> movw %ax, %ss # setup the
> movw $start, %sp # stack
> movw %es, %cx # save PXENV+ segment
> movw %ax, %ds # setup the
> movw %ax, %es # data segments
> andl $0xffff, %ecx # clear upper words
> andl $0xffff, %ebx # of %ebx and %ecx
> shll $4, %ecx # calculate the offset of
> addl %ebx, %ecx # the PXENV+ struct and
> pushl %ecx # save it on the stack
> movw $welcome_msg, %si # %ds:(%si) -> welcome message
> callw putstr # display the welcome message
101,113c101,112
< movw $bootinfo_msg, %si // %ds:(%si) -> boot args
< // message
< callw putstr // display the message
< movw $MEM_ARG, %bx // %ds:(%bx) -> boot args
< movw %bx, %di // %es:(%di) -> boot args
< xorl %eax, %eax // zero %eax
< movw $(MEM_ARG_SIZE/4), %cx // Size of arguments in 32-bit
< // dwords
< rep // Clear the arguments
< stosl // to zero
< orb $KARGS_FLAGS_PXE, 0x8(%bx) // kargs->bootflags |=
< // KARGS_FLAGS_PXE
< popl 0xc(%bx) // kargs->pxeinfo = *PXENV+
---
> movw $bootinfo_msg, %si # %ds:(%si) -> boot args message
> callw putstr # display the message
> movw $MEM_ARG, %bx # %ds:(%bx) -> boot args
> movw %bx, %di # %es:(%di) -> boot args
> xorl %eax, %eax # zero %eax
> movw $(MEM_ARG_SIZE/4), %cx # Size of arguments in 32-bit
> # dwords
> rep # Clear the arguments
> stosl # to zero
> orb $KARGS_FLAGS_PXE, 0x8(%bx) # kargs->bootflags |=
> # KARGS_FLAGS_PXE
> popl 0xc(%bx) # kargs->pxeinfo = *PXENV+
118c117
< orl $RB_SERIAL, (%bx) // enable serial console
---
> orl $RB_SERIAL, (%bx) # enable serial console
125,127c124,126
< testb $KEYBOARD_BIT, MEM_BIOS_KEYBOARD // keyboard present?
< jnz keyb // yes, so skip
< orl $RB_SERIAL, (%bx) // enable serial console
---
> testb $KEYBOARD_BIT, MEM_BIOS_KEYBOARD # keyboard present?
> jnz keyb # yes, so skip
> orl $RB_SERIAL, (%bx) # enable serial console
133c132
< callw seta20 // Turn A20 on
---
> callw seta20 # Turn A20 on
137,151c136,150
< movw $relocate_msg, %si // Display the
< callw putstr // relocation message
< movl end+AOUT_ENTRY, %edi // %edi is the destination
< movl $(end+AOUT_HEADER), %esi // %esi is
< // the start of the text
< // segment
< movl end+AOUT_TEXT, %ecx // %ecx = length of the text
< // segment
< lgdt gdtdesc // setup our own gdt
< cli // turn off interrupts
< movl %cr0, %eax // Turn on
< orb $0x1, %al // protected
< movl %eax, %cr0 // mode
< ljmp $SEL_SCODE,$pm_start // long jump to clear the
< // instruction pre-fetch queue
---
> movw $relocate_msg, %si # Display the
> callw putstr # relocation message
> movl end+AOUT_ENTRY, %edi # %edi is the destination
> movl $(end+AOUT_HEADER), %esi # %esi is
> # the start of the text
> # segment
> movl end+AOUT_TEXT, %ecx # %ecx = length of the text
> # segment
> lgdt gdtdesc # setup our own gdt
> cli # turn off interrupts
> movl %cr0, %eax # Turn on
> orb $0x1, %al # protected
> movl %eax, %cr0 # mode
> ljmp $SEL_SCODE,$pm_start # long jump to clear the
> # instruction pre-fetch queue
153,175c152,174
< pm_start: movw $SEL_SDATA, %ax // Initialize
< movw %ax, %ds // %ds and
< movw %ax, %es // %es to a flat selector
< rep // Relocate the
< movsb // text segment
< addl $(MEM_PAGE_SIZE - 1), %edi // pad %edi out to a new page
< andl $~(MEM_PAGE_SIZE - 1), %edi // for the data segment
< movl end+AOUT_DATA, %ecx // size of the data segment
< rep // Relocate the
< movsb // data segment
< movl end+AOUT_BSS, %ecx // size of the bss
< xorl %eax, %eax // zero %eax
< addb $3, %cl // round %ecx up to
< shrl $2, %ecx // a multiple of 4
< rep // zero the
< stosl // bss
< movl end+AOUT_ENTRY, %esi // %esi -> relocated loader
< addl $MEM_BTX_OFFSET, %esi // %esi -> BTX in the loader
< movl $MEM_BTX_ADDRESS, %edi // %edi -> where BTX needs to go
< movzwl 0xa(%esi), %ecx // %ecx -> length of BTX
< rep // Relocate
< movsb // BTX
< ljmp $SEL_SCODE16,$pm_16 // Jump to 16-bit PM
---
> pm_start: movw $SEL_SDATA, %ax # Initialize
> movw %ax, %ds # %ds and
> movw %ax, %es # %es to a flat selector
> rep # Relocate the
> movsb # text segment
> addl $(MEM_PAGE_SIZE - 1), %edi # pad %edi out to a new page
> andl $~(MEM_PAGE_SIZE - 1), %edi # for the data segment
> movl end+AOUT_DATA, %ecx # size of the data segment
> rep # Relocate the
> movsb # data segment
> movl end+AOUT_BSS, %ecx # size of the bss
> xorl %eax, %eax # zero %eax
> addb $3, %cl # round %ecx up to
> shrl $2, %ecx # a multiple of 4
> rep # zero the
> stosl # bss
> movl end+AOUT_ENTRY, %esi # %esi -> relocated loader
> addl $MEM_BTX_OFFSET, %esi # %esi -> BTX in the loader
> movl $MEM_BTX_ADDRESS, %edi # %edi -> where BTX needs to go
> movzwl 0xa(%esi), %ecx # %ecx -> length of BTX
> rep # Relocate
> movsb # BTX
> ljmp $SEL_SCODE16,$pm_16 # Jump to 16-bit PM
177,185c176,184
< pm_16: movw $SEL_RDATA, %ax // Initialize
< movw %ax, %ds // %ds and
< movw %ax, %es // %es to a real mode selector
< movl %cr0, %eax // Turn off
< andb $~0x1, %al // protected
< movl %eax, %cr0 // mode
< ljmp $0,$pm_end // Long jump to clear the
< // instruction pre-fetch queue
< pm_end: sti // Turn interrupts back on now
---
> pm_16: movw $SEL_RDATA, %ax # Initialize
> movw %ax, %ds # %ds and
> movw %ax, %es # %es to a real mode selector
> movl %cr0, %eax # Turn off
> andb $~0x1, %al # protected
> movl %eax, %cr0 # mode
> ljmp $0,$pm_end # Long jump to clear the
> # instruction pre-fetch queue
> pm_end: sti # Turn interrupts back on now
189,196c188,195
< xorw %ax, %ax // zero %ax and set
< movw %ax, %ds // %ds and %es
< movw %ax, %es // to segment 0
< movw $MEM_BTX_CLIENT, %di // Prepare to relocate
< movw $btx_client, %si // the simple btx client
< movw $(btx_client_end-btx_client), %cx // length of btx client
< rep // Relocate the
< movsb // simple BTX client
---
> xorw %ax, %ax # zero %ax and set
> movw %ax, %ds # %ds and %es
> movw %ax, %es # to segment 0
> movw $MEM_BTX_CLIENT, %di # Prepare to relocate
> movw $btx_client, %si # the simple btx client
> movw $(btx_client_end-btx_client), %cx # length of btx client
> rep # Relocate the
> movsb # simple BTX client
200,205c199,203
< movw $MEM_ARG, %si // where the args are at now
< movw $MEM_ARG_BTX, %di // where the args are moving to
< movw $(MEM_ARG_SIZE/4), %cx // size of the arguments in
< // longs
< rep // Relocate
< movsl // the words
---
> movw $MEM_ARG, %si # where the args are at now
> movw $MEM_ARG_BTX, %di # where the args are moving to
> movw $(MEM_ARG_SIZE/4), %cx # size of the arguments in longs
> rep # Relocate
> movsl # the words
209,211c207,209
< movl end+AOUT_ENTRY, %eax // load the entry point
< stosl // add it to the end of the
< // arguments
---
> movl end+AOUT_ENTRY, %eax # load the entry point
> stosl # add it to the end of the
> # arguments
215,217c213,215
< movw $jump_message, %si // Display the
< callw putstr // jump message
< ljmp $0,$MEM_BTX_ENTRY // Jump to the BTX entry point
---
> movw $jump_message, %si # Display the
> callw putstr # jump message
> ljmp $0,$MEM_BTX_ENTRY # Jump to the BTX entry point
222,230c220,227
< putstr: lodsb // load %al from %ds:(%si)
< testb %al,%al // stop at null
< jnz putc // if the char != null,
< // output it
< retw // return when null is hit
< putc: movw $0x7,%bx // attribute for output
< movb $0xe,%ah // BIOS: put_char
< int $0x10 // call BIOS, print char in %al
< jmp putstr // keep looping
---
> putstr: lodsb # load %al from %ds:(%si)
> testb %al,%al # stop at null
> jnz putc # if the char != null, output it
> retw # return when null is hit
> putc: movw $0x7,%bx # attribute for output
> movb $0xe,%ah # BIOS: put_char
> int $0x10 # call BIOS, print char in %al
> jmp putstr # keep looping
235,247c232,244
< seta20: cli // Disable interrupts
< seta20.1: inb $0x64,%al // Get status
< testb $0x2,%al // Busy?
< jnz seta20.1 // Yes
< movb $0xd1,%al // Command: Write
< outb %al,$0x64 // output port
< seta20.2: inb $0x64,%al // Get status
< testb $0x2,%al // Busy?
< jnz seta20.2 // Yes
< movb $0xdf,%al // Enable
< outb %al,$0x60 // A20
< sti // Enable interrupts
< retw // To caller
---
> seta20: cli # Disable interrupts
> seta20.1: inb $0x64,%al # Get status
> testb $0x2,%al # Busy?
> jnz seta20.1 # Yes
> movb $0xd1,%al # Command: Write
> outb %al,$0x64 # output port
> seta20.2: inb $0x64,%al # Get status
> testb $0x2,%al # Busy?
> jnz seta20.2 # Yes
> movb $0xdf,%al # Enable
> outb %al,$0x60 # A20
> sti # Enable interrupts
> retw # To caller
254,267c251,263
< // %ds:(%esi) -> end
< // of boot[12] args
< movl $(MEM_ARG_SIZE/4), %ecx // Number of words to push
< std // Go backwards
< push_arg: lodsl // Read argument
< pushl %eax // Push it onto the stack
< loop push_arg // Push all of the arguments
< cld // In case anyone depends
< // on this
< pushl MEM_ARG_BTX-MEM_BTX_CLIENT+MEM_ARG_SIZE // Entry point of
< // the loader
< pushl %eax // Emulate a near call
< movl $0x1, %eax // 'exec' system call
< int $INT_SYS // BTX system call
---
> # %ds:(%esi) -> end
> # of boot[12] args
> movl $(MEM_ARG_SIZE/4), %ecx # Number of words to push
> std # Go backwards
> push_arg: lodsl # Read argument
> pushl %eax # Push it onto the stack
> loop push_arg # Push all of the arguments
> cld # In case anyone depends on this
> pushl MEM_ARG_BTX-MEM_BTX_CLIENT+MEM_ARG_SIZE # Entry point of
> # the loader
> pushl %eax # Emulate a near call
> movl $0x1, %eax # 'exec' system call
> int $INT_SYS # BTX system call
275,279c271,275
< gdt: .word 0x0,0x0,0x0,0x0 // Null entry
< .word 0xffff,0x0,0x9200,0xcf // SEL_SDATA
< .word 0xffff,0x0,0x9200,0x0 // SEL_RDATA
< .word 0xffff,0x0,0x9a00,0xcf // SEL_SCODE (32-bit)
< .word 0xffff,0x0,0x9a00,0x8f // SEL_SCODE16 (16-bit)
---
> gdt: .word 0x0,0x0,0x0,0x0 # Null entry
> .word 0xffff,0x0,0x9200,0xcf # SEL_SDATA
> .word 0xffff,0x0,0x9200,0x0 # SEL_RDATA
> .word 0xffff,0x0,0x9a00,0xcf # SEL_SCODE (32-bit)
> .word 0xffff,0x0,0x9a00,0x8f # SEL_SCODE16 (16-bit)
284,285c280,281
< gdtdesc: .word gdt.1-gdt-1 // Limit
< .long gdt // Base
---
> gdtdesc: .word gdt.1-gdt-1 # Limit
> .long gdt # Base
< * $FreeBSD: head/sys/boot/i386/pxeldr/pxeldr.S 128716 2004-04-28 14:31:44Z ru $
---
> * $FreeBSD: head/sys/boot/i386/pxeldr/pxeldr.S 129240 2004-05-14 20:29:30Z ru $
22c22
< * boot[12] environment (protected mode, a bootinfo struct, etc.) and then jumps
---
> * boot[12] environment (protected mode, a bootinfo struct, etc.), and then jumps
31,40c31,40
< .set MEM_PAGE_SIZE,0x1000 // memory page size, 4k
< .set MEM_ARG,0x900 // Arguments at start
< .set MEM_ARG_BTX,0xa100 // Where we move them to so the
< // BTX client can see them
< .set MEM_ARG_SIZE,0x18 // Size of the arguments
< .set MEM_BTX_ADDRESS,0x9000 // where BTX lives
< .set MEM_BTX_ENTRY,0x9010 // where BTX starts to execute
< .set MEM_BTX_OFFSET,MEM_PAGE_SIZE // offset of BTX in the loader
< .set MEM_BTX_CLIENT,0xa000 // where BTX clients live
< .set MEM_BIOS_KEYBOARD,0x496 // BDA byte with keyboard bit
---
> .set MEM_PAGE_SIZE,0x1000 # memory page size, 4k
> .set MEM_ARG,0x900 # Arguments at start
> .set MEM_ARG_BTX,0xa100 # Where we move them to so the
> # BTX client can see them
> .set MEM_ARG_SIZE,0x18 # Size of the arguments
> .set MEM_BTX_ADDRESS,0x9000 # where BTX lives
> .set MEM_BTX_ENTRY,0x9010 # where BTX starts to execute
> .set MEM_BTX_OFFSET,MEM_PAGE_SIZE # offset of BTX in the loader
> .set MEM_BTX_CLIENT,0xa000 # where BTX clients live
> .set MEM_BIOS_KEYBOARD,0x496 # BDA byte with keyboard bit
44,49c44,49
< .set AOUT_TEXT,0x04 // text segment size
< .set AOUT_DATA,0x08 // data segment size
< .set AOUT_BSS,0x0c // zero'd BSS size
< .set AOUT_SYMBOLS,0x10 // symbol table
< .set AOUT_ENTRY,0x14 // entry point
< .set AOUT_HEADER,MEM_PAGE_SIZE // size of the a.out header
---
> .set AOUT_TEXT,0x04 # text segment size
> .set AOUT_DATA,0x08 # data segment size
> .set AOUT_BSS,0x0c # zero'd BSS size
> .set AOUT_SYMBOLS,0x10 # symbol table
> .set AOUT_ENTRY,0x14 # entry point
> .set AOUT_HEADER,MEM_PAGE_SIZE # size of the a.out header
53,54c53,54
< .set KARGS_FLAGS_PXE,0x2 // flag to indicate booting from
< // PXE loader
---
> .set KARGS_FLAGS_PXE,0x2 # flag to indicate booting from
> # PXE loader
58c58
< .set RB_SERIAL,0x1000 // serial console
---
> .set RB_SERIAL,0x1000 # serial console
62,65c62,65
< .set SEL_SDATA,0x8 // Supervisor data
< .set SEL_RDATA,0x10 // Real mode data
< .set SEL_SCODE,0x18 // PM-32 code
< .set SEL_SCODE16,0x20 // PM-16 code
---
> .set SEL_SDATA,0x8 # Supervisor data
> .set SEL_RDATA,0x10 # Real mode data
> .set SEL_SCODE,0x18 # PM-32 code
> .set SEL_SCODE16,0x20 # PM-16 code
69c69
< .set INT_SYS,0x30 // BTX syscall interrupt
---
> .set INT_SYS,0x30 # BTX syscall interrupt
84,97c84,97
< start: cld // string ops inc
< xorw %ax, %ax // zero %ax
< movw %ax, %ss // setup the
< movw $start, %sp // stack
< movw %es, %cx // save PXENV+ segment
< movw %ax, %ds // setup the
< movw %ax, %es // data segments
< andl $0xffff, %ecx // clear upper words
< andl $0xffff, %ebx // of %ebx and %ecx
< shll $4, %ecx // calculate the offset of
< addl %ebx, %ecx // the PXENV+ struct and
< pushl %ecx // save it on the stack
< movw $welcome_msg, %si // %ds:(%si) -> welcome message
< callw putstr // display the welcome message
---
> start: cld # string ops inc
> xorw %ax, %ax # zero %ax
> movw %ax, %ss # setup the
> movw $start, %sp # stack
> movw %es, %cx # save PXENV+ segment
> movw %ax, %ds # setup the
> movw %ax, %es # data segments
> andl $0xffff, %ecx # clear upper words
> andl $0xffff, %ebx # of %ebx and %ecx
> shll $4, %ecx # calculate the offset of
> addl %ebx, %ecx # the PXENV+ struct and
> pushl %ecx # save it on the stack
> movw $welcome_msg, %si # %ds:(%si) -> welcome message
> callw putstr # display the welcome message
101,113c101,112
< movw $bootinfo_msg, %si // %ds:(%si) -> boot args
< // message
< callw putstr // display the message
< movw $MEM_ARG, %bx // %ds:(%bx) -> boot args
< movw %bx, %di // %es:(%di) -> boot args
< xorl %eax, %eax // zero %eax
< movw $(MEM_ARG_SIZE/4), %cx // Size of arguments in 32-bit
< // dwords
< rep // Clear the arguments
< stosl // to zero
< orb $KARGS_FLAGS_PXE, 0x8(%bx) // kargs->bootflags |=
< // KARGS_FLAGS_PXE
< popl 0xc(%bx) // kargs->pxeinfo = *PXENV+
---
> movw $bootinfo_msg, %si # %ds:(%si) -> boot args message
> callw putstr # display the message
> movw $MEM_ARG, %bx # %ds:(%bx) -> boot args
> movw %bx, %di # %es:(%di) -> boot args
> xorl %eax, %eax # zero %eax
> movw $(MEM_ARG_SIZE/4), %cx # Size of arguments in 32-bit
> # dwords
> rep # Clear the arguments
> stosl # to zero
> orb $KARGS_FLAGS_PXE, 0x8(%bx) # kargs->bootflags |=
> # KARGS_FLAGS_PXE
> popl 0xc(%bx) # kargs->pxeinfo = *PXENV+
118c117
< orl $RB_SERIAL, (%bx) // enable serial console
---
> orl $RB_SERIAL, (%bx) # enable serial console
125,127c124,126
< testb $KEYBOARD_BIT, MEM_BIOS_KEYBOARD // keyboard present?
< jnz keyb // yes, so skip
< orl $RB_SERIAL, (%bx) // enable serial console
---
> testb $KEYBOARD_BIT, MEM_BIOS_KEYBOARD # keyboard present?
> jnz keyb # yes, so skip
> orl $RB_SERIAL, (%bx) # enable serial console
133c132
< callw seta20 // Turn A20 on
---
> callw seta20 # Turn A20 on
137,151c136,150
< movw $relocate_msg, %si // Display the
< callw putstr // relocation message
< movl end+AOUT_ENTRY, %edi // %edi is the destination
< movl $(end+AOUT_HEADER), %esi // %esi is
< // the start of the text
< // segment
< movl end+AOUT_TEXT, %ecx // %ecx = length of the text
< // segment
< lgdt gdtdesc // setup our own gdt
< cli // turn off interrupts
< movl %cr0, %eax // Turn on
< orb $0x1, %al // protected
< movl %eax, %cr0 // mode
< ljmp $SEL_SCODE,$pm_start // long jump to clear the
< // instruction pre-fetch queue
---
> movw $relocate_msg, %si # Display the
> callw putstr # relocation message
> movl end+AOUT_ENTRY, %edi # %edi is the destination
> movl $(end+AOUT_HEADER), %esi # %esi is
> # the start of the text
> # segment
> movl end+AOUT_TEXT, %ecx # %ecx = length of the text
> # segment
> lgdt gdtdesc # setup our own gdt
> cli # turn off interrupts
> movl %cr0, %eax # Turn on
> orb $0x1, %al # protected
> movl %eax, %cr0 # mode
> ljmp $SEL_SCODE,$pm_start # long jump to clear the
> # instruction pre-fetch queue
153,175c152,174
< pm_start: movw $SEL_SDATA, %ax // Initialize
< movw %ax, %ds // %ds and
< movw %ax, %es // %es to a flat selector
< rep // Relocate the
< movsb // text segment
< addl $(MEM_PAGE_SIZE - 1), %edi // pad %edi out to a new page
< andl $~(MEM_PAGE_SIZE - 1), %edi // for the data segment
< movl end+AOUT_DATA, %ecx // size of the data segment
< rep // Relocate the
< movsb // data segment
< movl end+AOUT_BSS, %ecx // size of the bss
< xorl %eax, %eax // zero %eax
< addb $3, %cl // round %ecx up to
< shrl $2, %ecx // a multiple of 4
< rep // zero the
< stosl // bss
< movl end+AOUT_ENTRY, %esi // %esi -> relocated loader
< addl $MEM_BTX_OFFSET, %esi // %esi -> BTX in the loader
< movl $MEM_BTX_ADDRESS, %edi // %edi -> where BTX needs to go
< movzwl 0xa(%esi), %ecx // %ecx -> length of BTX
< rep // Relocate
< movsb // BTX
< ljmp $SEL_SCODE16,$pm_16 // Jump to 16-bit PM
---
> pm_start: movw $SEL_SDATA, %ax # Initialize
> movw %ax, %ds # %ds and
> movw %ax, %es # %es to a flat selector
> rep # Relocate the
> movsb # text segment
> addl $(MEM_PAGE_SIZE - 1), %edi # pad %edi out to a new page
> andl $~(MEM_PAGE_SIZE - 1), %edi # for the data segment
> movl end+AOUT_DATA, %ecx # size of the data segment
> rep # Relocate the
> movsb # data segment
> movl end+AOUT_BSS, %ecx # size of the bss
> xorl %eax, %eax # zero %eax
> addb $3, %cl # round %ecx up to
> shrl $2, %ecx # a multiple of 4
> rep # zero the
> stosl # bss
> movl end+AOUT_ENTRY, %esi # %esi -> relocated loader
> addl $MEM_BTX_OFFSET, %esi # %esi -> BTX in the loader
> movl $MEM_BTX_ADDRESS, %edi # %edi -> where BTX needs to go
> movzwl 0xa(%esi), %ecx # %ecx -> length of BTX
> rep # Relocate
> movsb # BTX
> ljmp $SEL_SCODE16,$pm_16 # Jump to 16-bit PM
177,185c176,184
< pm_16: movw $SEL_RDATA, %ax // Initialize
< movw %ax, %ds // %ds and
< movw %ax, %es // %es to a real mode selector
< movl %cr0, %eax // Turn off
< andb $~0x1, %al // protected
< movl %eax, %cr0 // mode
< ljmp $0,$pm_end // Long jump to clear the
< // instruction pre-fetch queue
< pm_end: sti // Turn interrupts back on now
---
> pm_16: movw $SEL_RDATA, %ax # Initialize
> movw %ax, %ds # %ds and
> movw %ax, %es # %es to a real mode selector
> movl %cr0, %eax # Turn off
> andb $~0x1, %al # protected
> movl %eax, %cr0 # mode
> ljmp $0,$pm_end # Long jump to clear the
> # instruction pre-fetch queue
> pm_end: sti # Turn interrupts back on now
189,196c188,195
< xorw %ax, %ax // zero %ax and set
< movw %ax, %ds // %ds and %es
< movw %ax, %es // to segment 0
< movw $MEM_BTX_CLIENT, %di // Prepare to relocate
< movw $btx_client, %si // the simple btx client
< movw $(btx_client_end-btx_client), %cx // length of btx client
< rep // Relocate the
< movsb // simple BTX client
---
> xorw %ax, %ax # zero %ax and set
> movw %ax, %ds # %ds and %es
> movw %ax, %es # to segment 0
> movw $MEM_BTX_CLIENT, %di # Prepare to relocate
> movw $btx_client, %si # the simple btx client
> movw $(btx_client_end-btx_client), %cx # length of btx client
> rep # Relocate the
> movsb # simple BTX client
200,205c199,203
< movw $MEM_ARG, %si // where the args are at now
< movw $MEM_ARG_BTX, %di // where the args are moving to
< movw $(MEM_ARG_SIZE/4), %cx // size of the arguments in
< // longs
< rep // Relocate
< movsl // the words
---
> movw $MEM_ARG, %si # where the args are at now
> movw $MEM_ARG_BTX, %di # where the args are moving to
> movw $(MEM_ARG_SIZE/4), %cx # size of the arguments in longs
> rep # Relocate
> movsl # the words
209,211c207,209
< movl end+AOUT_ENTRY, %eax // load the entry point
< stosl // add it to the end of the
< // arguments
---
> movl end+AOUT_ENTRY, %eax # load the entry point
> stosl # add it to the end of the
> # arguments
215,217c213,215
< movw $jump_message, %si // Display the
< callw putstr // jump message
< ljmp $0,$MEM_BTX_ENTRY // Jump to the BTX entry point
---
> movw $jump_message, %si # Display the
> callw putstr # jump message
> ljmp $0,$MEM_BTX_ENTRY # Jump to the BTX entry point
222,230c220,227
< putstr: lodsb // load %al from %ds:(%si)
< testb %al,%al // stop at null
< jnz putc // if the char != null,
< // output it
< retw // return when null is hit
< putc: movw $0x7,%bx // attribute for output
< movb $0xe,%ah // BIOS: put_char
< int $0x10 // call BIOS, print char in %al
< jmp putstr // keep looping
---
> putstr: lodsb # load %al from %ds:(%si)
> testb %al,%al # stop at null
> jnz putc # if the char != null, output it
> retw # return when null is hit
> putc: movw $0x7,%bx # attribute for output
> movb $0xe,%ah # BIOS: put_char
> int $0x10 # call BIOS, print char in %al
> jmp putstr # keep looping
235,247c232,244
< seta20: cli // Disable interrupts
< seta20.1: inb $0x64,%al // Get status
< testb $0x2,%al // Busy?
< jnz seta20.1 // Yes
< movb $0xd1,%al // Command: Write
< outb %al,$0x64 // output port
< seta20.2: inb $0x64,%al // Get status
< testb $0x2,%al // Busy?
< jnz seta20.2 // Yes
< movb $0xdf,%al // Enable
< outb %al,$0x60 // A20
< sti // Enable interrupts
< retw // To caller
---
> seta20: cli # Disable interrupts
> seta20.1: inb $0x64,%al # Get status
> testb $0x2,%al # Busy?
> jnz seta20.1 # Yes
> movb $0xd1,%al # Command: Write
> outb %al,$0x64 # output port
> seta20.2: inb $0x64,%al # Get status
> testb $0x2,%al # Busy?
> jnz seta20.2 # Yes
> movb $0xdf,%al # Enable
> outb %al,$0x60 # A20
> sti # Enable interrupts
> retw # To caller
254,267c251,263
< // %ds:(%esi) -> end
< // of boot[12] args
< movl $(MEM_ARG_SIZE/4), %ecx // Number of words to push
< std // Go backwards
< push_arg: lodsl // Read argument
< pushl %eax // Push it onto the stack
< loop push_arg // Push all of the arguments
< cld // In case anyone depends
< // on this
< pushl MEM_ARG_BTX-MEM_BTX_CLIENT+MEM_ARG_SIZE // Entry point of
< // the loader
< pushl %eax // Emulate a near call
< movl $0x1, %eax // 'exec' system call
< int $INT_SYS // BTX system call
---
> # %ds:(%esi) -> end
> # of boot[12] args
> movl $(MEM_ARG_SIZE/4), %ecx # Number of words to push
> std # Go backwards
> push_arg: lodsl # Read argument
> pushl %eax # Push it onto the stack
> loop push_arg # Push all of the arguments
> cld # In case anyone depends on this
> pushl MEM_ARG_BTX-MEM_BTX_CLIENT+MEM_ARG_SIZE # Entry point of
> # the loader
> pushl %eax # Emulate a near call
> movl $0x1, %eax # 'exec' system call
> int $INT_SYS # BTX system call
275,279c271,275
< gdt: .word 0x0,0x0,0x0,0x0 // Null entry
< .word 0xffff,0x0,0x9200,0xcf // SEL_SDATA
< .word 0xffff,0x0,0x9200,0x0 // SEL_RDATA
< .word 0xffff,0x0,0x9a00,0xcf // SEL_SCODE (32-bit)
< .word 0xffff,0x0,0x9a00,0x8f // SEL_SCODE16 (16-bit)
---
> gdt: .word 0x0,0x0,0x0,0x0 # Null entry
> .word 0xffff,0x0,0x9200,0xcf # SEL_SDATA
> .word 0xffff,0x0,0x9200,0x0 # SEL_RDATA
> .word 0xffff,0x0,0x9a00,0xcf # SEL_SCODE (32-bit)
> .word 0xffff,0x0,0x9a00,0x8f # SEL_SCODE16 (16-bit)
284,285c280,281
< gdtdesc: .word gdt.1-gdt-1 // Limit
< .long gdt // Base
---
> gdtdesc: .word gdt.1-gdt-1 # Limit
> .long gdt # Base