!
! setup.S Copyright (C) 1991, 1992 Linus Torvalds
!
! setup.s is responsible for getting the system data from the BIOS,
! and putting them into the appropriate places in system memory.
! both setup.s and system has been loaded by the bootblock.
!
! This code asks the bios for memory/disk/other parameters, and
! puts them in a "safe" place: 0x90000-0x901FF, ie where the
! boot-block used to be. It is then up to the protected mode
! system to read them from there before the area is overwritten
! for buffer-blocks.
!
! Move PS/2 aux init code to psaux.c
! (troyer@saifr00.cfsat.Honeywell.COM) 03Oct92
!
! some changes and additional features by Christoph Niemann, March 1993
! (niemann@rubdv15.ETDV.Ruhr-Uni-Bochum.De)
!

! NOTE! These had better be the same as in bootsect.s!
#include <linux/config.h>
#include <linux/segment.h>

#ifndef SVGA_MODE
#define SVGA_MODE ASK_VGA
#endif

INITSEG = DEF_INITSEG ! we move boot here - out of the way
SYSSEG = DEF_SYSSEG ! system loaded at 0x10000 (65536).
SETUPSEG = DEF_SETUPSEG ! this is the current segment

.globl begtext, begdata, begbss, endtext, enddata, endbss
.text
begtext:
.data
begdata:
.bss
begbss:
.text

! 程序入口
entry start
start:

! ok, the read went well so we get current cursor position and save it for
! posterity.
! ok，读取正常，现在我们获取当前光标位置然后保存

! 设定ds段位置
mov ax,#INITSEG ! this is done in bootsect already, but...
mov ds,ax

! Get memory size (extended mem, kB)
! 获取内存
mov ah,#0x88
int 0x15
mov [2],ax

! set the keyboard repeat rate to the max
! 设置键盘最大重复速率
mov ax,#0x0305
xor bx,bx ! clear bx
int 0x16

! check for EGA/VGA and some config parameters
! 检测EGA/VGA并配置参数

mov ah,#0x12
mov bl,#0x10
int 0x10
mov [8],ax
mov [10],bx
mov [12],cx
mov ax,#0x5019
cmp bl,#0x10
je novga
mov ax,#0x1a00 ! Added check for EGA/VGA discrimination
int 0x10
mov bx,ax
mov ax,#0x5019
cmp bl,#0x1a ! 1a means VGA, anything else EGA or lower
jne novga
call chsvga ! 子函数，过程比较简单，但是读取的可能配置比较多
novga: mov [14],ax
mov ah,#0x03 ! read cursor pos
xor bh,bh ! clear bh
int 0x10 ! save it in known place, con_init fetches
mov [0],dx ! it from 0x90000.

! Get video-card data:
! 获取显卡数据

mov ah,#0x0f
int 0x10
mov [4],bx ! bh = display page
mov [6],ax ! al = video mode, ah = window width

! Get hd0 data
! 获取第一个硬盘数据

xor ax,ax ! clear ax
mov ds,ax
lds si,[4*0x41]
mov ax,#INITSEG
mov es,ax
mov di,#0x0080
mov cx,#0x10
cld
rep
movsb

! Get hd1 data
! 获取第二个硬盘数据

xor ax,ax ! clear ax
mov ds,ax
lds si,[4*0x46]
mov ax,#INITSEG
mov es,ax
mov di,#0x0090
mov cx,#0x10
cld
rep
movsb

! Check that there IS a hd1 :-)
! 检测硬盘数量
mov ax,#0x01500
mov dl,#0x81
int 0x13
jc no_disk1
cmp ah,#3
je is_disk1
no_disk1: ! 没有第二块硬盘的处理
mov ax,#INITSEG
mov es,ax
mov di,#0x0090
mov cx,#0x10
xor ax,ax ! clear ax
cld
rep
stosb
is_disk1:

! check for PS/2 pointing device
! 检测PS/2设备，应该是鼠标
mov ax,#INITSEG
mov ds,ax
mov [0x1ff],#0 ! default is no pointing device
int 0x11 ! int 0x11: equipment determination
test al,#0x04 ! check if pointing device installed
jz no_psmouse
mov [0x1ff],#0xaa ! device present
no_psmouse:
! now we want to move to protected mode ...
! 准备进入保护模式
cli ! no interrupts allowed !
mov al,#0x80 ! disable NMI for the bootup sequence
out #0x70,al

! first we move the system to its rightful place
! 首先我们移动system到正确的位置
mov ax,#0x100 ! start of destination segment
mov bx,#0x1000 ! start of source segment
cld ! ‘direction‘=0, movs moves forward
do_move: ! 上面是初始化，下面开始移动
mov es,ax ! destination segment
add ax,#0x100
cmp ax,#0x9000
jz end_move
mov ds,bx ! source segment
add bx,#0x100
sub di,di
sub si,si
mov cx,#0x800
rep
movsw
jmp do_move

! then we load the segment descriptors
! 移动完毕，我们加载段描述符

end_move:
mov ax,#SETUPSEG ! right, forgot this at first. didn‘t work :-)
mov ds,ax
! 加载idt
lidt idt_48 ! load idt with 0,0
! 加载gdt
lgdt gdt_48 ! load gdt with whatever appropriate

! that was painless, now we enable A20
! 设置完毕，我们现在准备打开A20地址线

call empty_8042
mov al,#0xD1 ! command write
out #0x64,al
call empty_8042
mov al,#0xDF ! A20 on
out #0x60,al
call empty_8042

! make sure any possible coprocessor is properly reset..
! 确保处理器正确设置

xor ax,ax
out #0xf0,al
call delay
out #0xf1,al
call delay

! well, that went ok, I hope. Now we have to reprogram the interrupts :-(
! we put them right after the intel-reserved hardware interrupts, at
! int 0x20-0x2F. There they won‘t mess up anything. Sadly IBM really
! messed this up with the original PC, and they haven‘t been able to
! rectify it afterwards. Thus the bios puts interrupts at 0x08-0x0f,
! which is used for the internal hardware interrupts as well. We just
! have to reprogram the 8259‘s, and it isn‘t fun.

! 重新设置中断
mov al,#0x11 ! initialization sequence
out #0x20,al ! send it to 8259A-1
call delay
out #0xA0,al ! and to 8259A-2
call delay
mov al,#0x20 ! start of hardware int‘s (0x20)
out #0x21,al
call delay
mov al,#0x28 ! start of hardware int‘s 2 (0x28)
out #0xA1,al
call delay
mov al,#0x04 ! 8259-1 is master
out #0x21,al
call delay
mov al,#0x02 ! 8259-2 is slave
out #0xA1,al
call delay
mov al,#0x01 ! 8086 mode for both
out #0x21,al
call delay
out #0xA1,al
call delay
mov al,#0xFF ! mask off all interrupts for now
out #0xA1,al
call delay
mov al,#0xFB ! mask all irq‘s but irq2 which
out #0x21,al ! is cascaded

! well, that certainly wasn‘t fun :-(. Hopefully it works, and we don‘t
! need no steenking BIOS anyway (except for the initial loading :-).
! The BIOS-routine wants lots of unnecessary data, and it‘s less
! "interesting" anyway. This is how REAL programmers do it.
!
! Well, now‘s the time to actually move into protected mode. To make
! things as simple as possible, we do no register set-up or anything,
! we let the gnu-compiled 32-bit programs do that. We just jump to
! absolute address 0x00000, in 32-bit protected mode.
!
! Note that the short jump isn‘t strictly needed, althought there are
! reasons why it might be a good idea. It won‘t hurt in any case.
!
! 打开地址线，进入保护模式
mov ax,#0x0001 ! protected mode (PE) bit
lmsw ax ! This is it!
jmp flush_instr
flush_instr:
jmpi 0x1000,KERNEL_CS ! jmp offset 1000 of segment 0x10 (cs)
! 跳转到cs段的偏移为0x1000处执行，即执行zBoot/head.s

! This routine checks that the keyboard command queue is empty
! (after emptying the output buffers)
!
! No timeout is used - if this hangs there is something wrong with
! the machine, and we probably couldn‘t proceed anyway.
empty_8042:
call delay
in al,#0x64 ! 8042 status port
test al,#1 ! output buffer?
jz no_output
call delay
in al,#0x60 ! read it
jmp empty_8042
no_output:
test al,#2 ! is input buffer full?
jnz empty_8042 ! yes - loop
ret
!
! Read a key and return the (US-)ascii code in al, scan code in ah
!
getkey:
xor ah,ah
int 0x16
ret

!
! Read a key with a timeout of 30 seconds. The cmos clock is used to get
! the time.
!
getkt:
call gettime
add al,#30 ! wait 30 seconds
cmp al,#60
jl lminute
sub al,#60
lminute:
mov cl,al
again: mov ah,#0x01
int 0x16
jnz getkey ! key pressed, so get it
call gettime
cmp al,cl
jne again
mov al,#0x20 ! timeout, return default char `space‘
ret

!
! Flush the keyboard buffer
!
flush: mov ah,#0x01
int 0x16
jz empty
xor ah,ah
int 0x16
jmp flush
empty: ret

!
! Read the cmos clock. Return the seconds in al
!
gettime:
push cx
mov ah,#0x02
int 0x1a
mov al,dh ! dh contains the seconds
and al,#0x0f
mov ah,dh
mov cl,#0x04
shr ah,cl
aad
pop cx
ret

!
! Delay is needed after doing i/o
!
delay:
.word 0x00eb ! jmp $+2
ret

! Routine trying to recognize type of SVGA-board present (if any)
! and if it recognize one gives the choices of resolution it offers.
! If one is found the resolution chosen is given by al,ah (rows,cols).

chsvga: cld
push ds
push cs
mov ax,[0x01fa]
pop ds
mov modesave,ax
mov ax,#0xc000
mov es,ax
mov ax,modesave
cmp ax,#NORMAL_VGA
je defvga
cmp ax,#EXTENDED_VGA
je vga50
cmp ax,#ASK_VGA
jne svga
lea si,msg1
call prtstr
call flush
nokey: call getkt
cmp al,#0x0d ! enter ?
je svga ! yes - svga selection
cmp al,#0x20 ! space ?
je defvga ! no - repeat
call beep
jmp nokey
defvga: mov ax,#0x5019
pop ds
ret
/* extended vga mode: 80x50 */
vga50:
mov ax,#0x1112
xor bl,bl
int 0x10 ! use 8x8 font set (50 lines on VGA)
mov ax,#0x1200
mov bl,#0x20
int 0x10 ! use alternate print screen
mov ax,#0x1201
mov bl,#0x34
int 0x10 ! turn off cursor emulation
mov ah,#0x01
mov cx,#0x0607
int 0x10 ! turn on cursor (scan lines 6 to 7)
pop ds
mov ax,#0x5032 ! return 80x50
ret
/* extended vga mode: 80x28 */
vga28:
pop ax ! clean the stack
mov ax,#0x1111
xor bl,bl
int 0x10 ! use 9x14 fontset (28 lines on VGA)
mov ah, #0x01
mov cx,#0x0b0c
int 0x10 ! turn on cursor (scan lines 11 to 12)
pop ds
mov ax,#0x501c ! return 80x28
ret
/* svga modes */
svga: cld
lea si,id9GXE ! Check for the #9GXE (jyanowit@orixa.mtholyoke.edu,thanks dlm40629@uxa.cso.uiuc.edu)
mov di,#0x49 ! id string is at c000:049
mov cx,#0x11 ! length of "Graphics Power By"
repe
cmpsb
jne of1280
is9GXE: lea si,dsc9GXE ! table of descriptions of video modes for BIOS
lea di,mo9GXE ! table of sizes of video modes for my BIOS
br selmod ! go ask for video mode
of1280: cld
lea si,idf1280 ! Check for Orchid F1280 (dingbat@diku.dk)
mov di,#0x10a ! id string is at c000:010a
mov cx,#0x21 ! length
repe
cmpsb
jne nf1280
isVRAM: lea si,dscf1280
lea di,mof1280
br selmod
nf1280: lea si,idVRAM
mov di,#0x10a
mov cx,#0x0c
repe
cmpsb
je isVRAM
cld
lea si,idati ! Check ATI ‘clues‘
mov di,#0x31
mov cx,#0x09
repe
cmpsb
jne noati
lea si,dscati
lea di,moati
br selmod
noati: mov ax,#0x200f ! Check Ahead ‘clues‘
mov dx,#0x3ce
out dx,ax
inc dx
in al,dx
cmp al,#0x20
je isahed
cmp al,#0x21
jne noahed
isahed: lea si,dscahead
lea di,moahead
br selmod
noahed: mov dx,#0x3c3 ! Check Chips & Tech. ‘clues‘
in al,dx
or al,#0x10
out dx,al
mov dx,#0x104
in al,dx
mov bl,al
mov dx,#0x3c3
in al,dx
and al,#0xef
out dx,al
cmp bl,[idcandt]
jne nocant
lea si,dsccandt
lea di,mocandt
br selmod
nocant: mov dx,#0x3d4 ! Check Cirrus ‘clues‘
mov al,#0x0c
out dx,al
inc dx
in al,dx
mov bl,al
xor al,al
out dx,al
dec dx
mov al,#0x1f
out dx,al
inc dx
in al,dx
mov bh,al
xor ah,ah
shl al,#4
mov cx,ax
mov al,bh
shr al,#4
add cx,ax
shl cx,#8
add cx,#6
mov ax,cx
mov dx,#0x3c4
out dx,ax
inc dx
in al,dx
and al,al
jnz nocirr
mov al,bh
out dx,al
in al,dx
cmp al,#0x01
jne nocirr
call rst3d4
lea si,dsccirrus
lea di,mocirrus
br selmod
rst3d4: mov dx,#0x3d4
mov al,bl
xor ah,ah
shl ax,#8
add ax,#0x0c
out dx,ax
ret
nocirr: call rst3d4 ! Check Everex ‘clues‘
mov ax,#0x7000
xor bx,bx
int 0x10
cmp al,#0x70
jne noevrx
shr dx,#4
cmp dx,#0x678
je istrid
cmp dx,#0x236
je istrid
lea si,dsceverex
lea di,moeverex
br selmod
istrid: lea cx,ev2tri
jmp cx
noevrx: lea si,idgenoa ! Check Genoa ‘clues‘
xor ax,ax
seg es
mov al,[0x37]
mov di,ax
mov cx,#0x04
dec si
dec di
l1: inc si
inc di
mov al,(si)
test al,al
jz l2
seg es
cmp al,(di)
l2: loope l1
cmp cx,#0x00
jne nogen
lea si,dscgenoa
lea di,mogenoa
br selmod
nogen: cld
lea si,idoakvga
mov di,#0x08
mov cx,#0x08
repe
cmpsb
jne nooak
lea si,dscoakvga
lea di,mooakvga
br selmod
nooak: cld
lea si,idparadise ! Check Paradise ‘clues‘
mov di,#0x7d
mov cx,#0x04
repe
cmpsb
jne nopara
lea si,dscparadise
lea di,moparadise
br selmod
nopara: mov dx,#0x3c4 ! Check Trident ‘clues‘
mov al,#0x0e
out dx,al
inc dx
in al,dx
xchg ah,al
xor al,al
out dx,al
in al,dx
xchg al,ah
mov bl,al ! Strange thing ... in the book this wasn‘t
and bl,#0x02 ! necessary but it worked on my card which
jz setb2 ! is a trident. Without it the screen goes
and al,#0xfd ! blurred ...
jmp clrb2 !
setb2: or al,#0x02 !
clrb2: out dx,al
and ah,#0x0f
cmp ah,#0x02
jne notrid
ev2tri: lea si,dsctrident
lea di,motrident
jmp selmod
notrid: mov dx,#0x3cd ! Check Tseng ‘clues‘
in al,dx ! Could things be this simple ! :-)
mov bl,al
mov al,#0x55
out dx,al
in al,dx
mov ah,al
mov al,bl
out dx,al
cmp ah,#0x55
jne notsen
lea si,dsctseng
lea di,motseng
jmp selmod
notsen: mov dx,#0x3cc ! Check Video7 ‘clues‘
in al,dx
mov dx,#0x3b4
and al,#0x01
jz even7
mov dx,#0x3d4
even7: mov al,#0x0c
out dx,al
inc dx
in al,dx
mov bl,al
mov al,#0x55
out dx,al
in al,dx
dec dx
mov al,#0x1f
out dx,al
inc dx
in al,dx
mov bh,al
dec dx
mov al,#0x0c
out dx,al
inc dx
mov al,bl
out dx,al
mov al,#0x55
xor al,#0xea
cmp al,bh
jne novid7
lea si,dscvideo7
lea di,movideo7
jmp selmod
novid7: lea si,dsunknown
lea di,mounknown
selmod: xor cx,cx
mov cl,(di)
mov ax,modesave
cmp ax,#ASK_VGA
je askmod
cmp ax,#NORMAL_VGA
je askmod
cmp al,cl
jl gotmode
push si
lea si,msg4
call prtstr
pop si
askmod: push si
lea si,msg2
call prtstr
pop si
push si
push cx
tbl: pop bx
push bx
mov al,bl
sub al,cl
call modepr
lodsw
xchg al,ah
call dprnt
xchg ah,al
push ax
mov al,#0x78
call prnt1
pop ax
call dprnt
push si
lea si,crlf ! print CR+LF
call prtstr
pop si
loop tbl
pop cx
lea si,msg3
call prtstr
pop si
add cl,#0x30
jmp nonum
nonumb: call beep
nonum: call getkey
cmp al,#0x30 ! ascii `0‘
jb nonumb
cmp al,#0x3a ! ascii `9‘
jbe number
cmp al,#0x61 ! ascii `a‘
jb nonumb
cmp al,#0x7a ! ascii `z‘
ja nonumb
sub al,#0x27
cmp al,cl
jae nonumb
sub al,#0x30
jmp gotmode
number: cmp al,cl
jae nonumb
sub al,#0x30
gotmode: xor ah,ah
or al,al
beq vga50
push ax
dec ax
beq vga28
add di,ax
mov al,(di)
int 0x10
pop ax
shl ax,#1
add si,ax
lodsw
pop ds
ret

! Routine to print asciiz-string at DS:SI

prtstr: lodsb
and al,al
jz fin
call prnt1
jmp prtstr
fin: ret

! Routine to print a decimal value on screen, the value to be
! printed is put in al (i.e 0-255).

dprnt: push ax
push cx
xor ah,ah ! Clear ah
mov cl,#0x0a
idiv cl
cmp al,#0x09
jbe lt100
call dprnt
jmp skip10
lt100: add al,#0x30
call prnt1
skip10: mov al,ah
add al,#0x30
call prnt1
pop cx
pop ax
ret

!
! Routine to print the mode number key on screen. Mode numbers
! 0-9 print the ascii values `0‘ to ‘9‘, 10-35 are represented by
! the letters `a‘ to `z‘. This routine prints some spaces around the
! mode no.
!

modepr: push ax
cmp al,#0x0a
jb digit ! Here is no check for number > 35
add al,#0x27
digit: add al,#0x30
mov modenr, al
push si
lea si, modestring
call prtstr
pop si
pop ax
ret

! Part of above routine, this one just prints ascii al

prnt1: push ax
push cx
xor bh,bh
mov cx,#0x01
mov ah,#0x0e
int 0x10
pop cx
pop ax
ret

beep: mov al,#0x07
jmp prnt1

gdt:
.word 0,0,0,0 ! dummy

.word 0,0,0,0 ! unused

.word 0x07FF ! 8Mb - limit=2047 (2048*4096=8Mb)
.word 0x0000 ! base address=0
.word 0x9A00 ! code read/exec
.word 0x00C0 ! granularity=4096, 386

.word 0x07FF ! 8Mb - limit=2047 (2048*4096=8Mb)
.word 0x0000 ! base address=0
.word 0x9200 ! data read/write
.word 0x00C0 ! granularity=4096, 386

idt_48:
.word 0 ! idt limit=0
.word 0,0 ! idt base=0L

gdt_48:
.word 0x800 ! gdt limit=2048, 256 GDT entries
.word 512+gdt,0x9 ! gdt base = 0X9xxxx

msg1: .ascii "Press <RETURN> to see SVGA-modes available, <SPACE> to continue or wait 30 secs."
db 0x0d, 0x0a, 0x0a, 0x00
msg2: .ascii "Mode: COLSxROWS:"
db 0x0d, 0x0a, 0x0a, 0x00
msg3: db 0x0d, 0x0a
.ascii "Choose mode by pressing the corresponding number or letter."
crlf: db 0x0d, 0x0a, 0x00
msg4: .ascii "You passed an undefined mode number to setup. Please choose a new mode."
db 0x0d, 0x0a, 0x0a, 0x07, 0x00
modestring: .ascii " "
modenr: db 0x00 ! mode number
.ascii ": "
db 0x00

idati: .ascii "761295520"
idcandt: .byte 0xa5
idgenoa: .byte 0x77, 0x00, 0x99, 0x66
idparadise: .ascii "VGA="
idoakvga: .ascii "OAK VGA "
idf1280: .ascii "Orchid Technology Fahrenheit 1280"
id9GXE: .ascii "Graphics Power By"
idVRAM: .ascii "Stealth VRAM"

! Manufacturer: Numofmodes+2: Mode:
! Number of modes is the number of chip-specific svga modes plus the extended
! modes available on any vga (currently 2)

moati: .byte 0x04, 0x23, 0x33
moahead: .byte 0x07, 0x22, 0x23, 0x24, 0x2f, 0x34
mocandt: .byte 0x04, 0x60, 0x61
mocirrus: .byte 0x06, 0x1f, 0x20, 0x22, 0x31
moeverex: .byte 0x0c, 0x03, 0x04, 0x07, 0x08, 0x0a, 0x0b, 0x16, 0x18, 0x21, 0x40
mogenoa: .byte 0x0c, 0x58, 0x5a, 0x60, 0x61, 0x62, 0x63, 0x64, 0x72, 0x74, 0x78
moparadise: .byte 0x04, 0x55, 0x54
motrident: .byte 0x09, 0x50, 0x51, 0x52, 0x57, 0x58, 0x59, 0x5a
motseng: .byte 0x07, 0x26, 0x2a, 0x23, 0x24, 0x22
movideo7: .byte 0x08, 0x40, 0x43, 0x44, 0x41, 0x42, 0x45
mooakvga: .byte 0x08, 0x00, 0x07, 0x4e, 0x4f, 0x50, 0x51
mo9GXE: .byte 0x04, 0x54, 0x55
mof1280: .byte 0x04, 0x54, 0x55
mounknown: .byte 0x02

! msb = Cols lsb = Rows:
! The first two modes are standard vga modes available on any vga.
! mode 0 is 80x50 and mode 1 is 80x28

dscati: .word 0x5032, 0x501c, 0x8419, 0x842c
dscahead: .word 0x5032, 0x501c, 0x842c, 0x8419, 0x841c, 0xa032, 0x5042
dsccandt: .word 0x5032, 0x501c, 0x8419, 0x8432
dsccirrus: .word 0x5032, 0x501c, 0x8419, 0x842c, 0x841e, 0x6425
dsceverex: .word 0x5032, 0x501c, 0x5022, 0x503c, 0x642b, 0x644b, 0x8419, 0x842c, 0x501e, 0x641b, 0xa040, 0x841e
dscgenoa: .word 0x5032, 0x501c, 0x5020, 0x642a, 0x8419, 0x841d, 0x8420, 0x842c, 0x843c, 0x503c, 0x5042, 0x644b
dscparadise: .word 0x5032, 0x501c, 0x8419, 0x842b
dsctrident: .word 0x5032, 0x501c, 0x501e, 0x502b, 0x503c, 0x8419, 0x841e, 0x842b, 0x843c
dsctseng: .word 0x5032, 0x501c, 0x503c, 0x6428, 0x8419, 0x841c, 0x842c
dscvideo7: .word 0x5032, 0x501c, 0x502b, 0x503c, 0x643c, 0x8419, 0x842c, 0x841c
dscoakvga: .word 0x5032, 0x501c, 0x2819, 0x5019, 0x503c, 0x843c, 0x8419, 0x842b
dscf1280: .word 0x5032, 0x501c, 0x842b, 0x8419
dsc9GXE: .word 0x5032, 0x501c, 0x842b, 0x8419
dsunknown: .word 0x5032, 0x501c
modesave: .word SVGA_MODE

.text
endtext:
.data
enddata:
.bss
endbss: