.code16
.section .boot2,"a"
- .extern ser_putchar
+ .set drive_number, 0x7bec
+ # reset floppy drive
+ xor %ax, %ax
+ movb drive_number, %dl
+ int $0x13
+
+ # load initial GDT/IDT
+ lgdt (gdt_lim)
+ lidt (idt_lim)
+ # enable protection
+ mov %cr0, %eax
+ or $1, %eax
+ mov %eax, %cr0
+ # inter-segment jump to set cs selector to segment 1
+ ljmp $0x8,$0f
+
+ .code32
+ # set all data selectors to segment 2
+0: mov $0x10, %ax
+ mov %ax, %ds
+ mov %ax, %ss
+ mov %ax, %es
+ mov %ax, %gs
+ mov %ax, %fs
- mov $0x13, %ax
- int $0x10
+ mov $0x18, %ax
+ ltr %ax
+
+ #movb $10, %al
+ #call ser_putchar
+
+ call clearscr
+
+ mov $hello, %esi
+ call putstr
+
+ # enable A20 line
+ call enable_a20
+
+ cli
+ hlt
+
+hello: .asciz "Switched to 32bit\n"
+
+ .align 4
+gdt_lim: .word 31
+gdt_base:.long gdt
+
+ .align 4
+idt_lim: .word 111
+idt_base:.long idt
+
+
+ .align 8
+gdt: # 0: null segment
+ .long 0
+ .long 0
+ # 1: code - base:0, lim:4g, G:4k, 32bit, avl, pres|app, dpl:0, type:code/non-conf/rd
+ .long 0x0000ffff
+ .long 0x00cf9a00
+ # 2: data - base:0, lim:4g, G:4k, 32bit, avl, pres|app, dpl:0, type:data/rw
+ .long 0x0000ffff
+ .long 0x00cf9200
+ # 3: dummy TSS - base:tss, lim:103, type avail 32bit TSS, byte-granular
+ .short 103
+ .short tss
+ .short 0x8900
+ .short 0
+
+
+ .align 8
+idt: .space 104
+ # trap gate 13: general protection fault
+ .short prot_fault
+ .short 0x8
+ # type: trap, present, default
+ .short 0x8f00
+ .short 0
+
+ .align 4
+tss: .space 104
+
+gpf_msg: .asciz "GPF "
+
+prot_fault:
+ mov (%esp), %eax
+ shr $3, %eax
+ call print_num
+ mov $64, %al
+ call putchar
+ mov 4(%esp), %eax
+ call print_num
+ mov $10, %al
+ call putchar
+ hlt
+
+ena20_msg: .asciz "A20 line enabled\n"
+foo_msg: .asciz "Foo\n"
+
+enable_a20:
+ mov $foo_msg, %esi
+ call putstr
+ jmp .La20done
+
+ call test_a20
+ jnc .La20done
+ call enable_a20_kbd
+ call test_a20
+ jnc .La20done
+ call enable_a20_fast
+ call test_a20
+ jnc .La20done
+ # keep trying ... we can't do anything useful without A20 anyway
+ jmp enable_a20
+.La20done:
+ mov $ena20_msg, %esi
+ call putstr
+ ret
+
+ # CF = 1 if A20 test fails (not enabled)
+test_a20:
+ mov $0x07c000, %ebx
+ mov $0x17c000, %edx
+ movl $0xbaadf00d, (%ebx)
+ movl $0xaabbcc42, (%edx)
+ subl $0xbaadf00d, (%ebx)
+ ret
+
+ena20_fast_msg: .asciz "Attempting fast A20 enable\n"
+
+enable_a20_fast:
+ mov $ena20_fast_msg, %esi
+ call putstr
+
+ in $0x92, %al
+ or $2, %al
+ out %al, $0x92
+ ret
+
+ .set KBC_DATA_PORT, 0x60
+ .set KBC_CMD_PORT, 0x64
+ .set KBC_STATUS_PORT, 0x64
+ .set KBC_CMD_RD_OUTPORT, 0xd0
+ .set KBC_CMD_WR_OUTPORT, 0xd1
+
+ .set KBC_STAT_OUT_RDY, 0x01
+ .set KBC_STAT_IN_FULL, 0x02
+
+ena20_kbd_msg: .asciz "Attempting KBD A20 enable\n"
+
+ # enable A20 line through the keyboard controller
+enable_a20_kbd:
+ mov $ena20_kbd_msg, %esi
+ call putstr
+
+ call kbc_wait_write
+ mov $KBC_CMD_WR_OUTPORT, %al
+ out %al, $KBC_CMD_PORT
+ call kbc_wait_write
+ mov $0xdf, %al
+ out %al, $KBC_DATA_PORT
+ ret
+
+ # wait until the keyboard controller is ready to accept another byte
+kbc_wait_write:
+ in $KBC_STATUS_PORT, %al
+ and $KBC_STAT_IN_FULL, %al
+ jnz kbc_wait_write
+ ret
+
+ # better print routines, since we're not constrainted by the 512b of
+ # the boot sector.
+cursor_x: .long 0
+cursor_y: .long 0
+
+putchar:
+ pusha
+ call ser_putchar
+
+ cmp $10, %al
+ jnz 0f
+ call video_newline
+ jmp 1f
+
+0: push %eax
+ mov cursor_y, %eax
+ mov $80, %ecx
+ mul %ecx
+ add cursor_x, %eax
+ mov %eax, %ebx
+ pop %eax
+
+ mov $0xb8000, %edx
+
+ # this looks retarded. in nasm: [ebx * 2 + edx]
+ mov %al, (%edx, %ebx, 2)
+ movb $7, 1(%edx, %ebx, 2)
+ incl cursor_x
+ cmpl $80, cursor_x
+ jnz 1f
+ call video_newline
+
+1: popa
+ ret
+
+ # expects string pointer in esi
+putstr:
+ mov (%esi), %al
+ cmp $0, %al
+ jz 0f
+ call putchar
+ inc %esi
+ jmp putstr
+0: ret
+
+ # expects number in eax
+print_num:
+ # save registers
+ pusha
+
+ mov $numbuf + 16, %esi
+ movb $0, (%esi)
+ mov $10, %ebx
+.Lconvloop:
+ xor %edx, %edx
+ div %ebx
+ add $48, %dl
+ dec %esi
+ mov %dl, (%esi)
+ cmp $0, %eax
+ jnz .Lconvloop
+
+ call putstr
+
+ # restore regs
+ popa
+ ret
+
+
+video_newline:
+ movl $0, cursor_x
+ incl cursor_y
+ cmpl $25, cursor_y
+ jnz 0f
+ call scrollup
+ decl cursor_y
+0: ret
+
+scrollup:
+ pusha
+ # move 80 * 24 lines from b8050 -> b8000
+ mov $0xb8000, %edi
+ mov $0xb8050, %esi
+ mov $480, %ecx
+ rep movsl
+ # clear last line (b8780)
+ mov $0xb8780, %edi
+ xor %eax, %eax
+ mov $20, %ecx
+ rep stosl
+ popa
+ ret
+
+clearscr:
+ mov $0xb8000, %edi
+ xor %eax, %eax
+ mov $500, %ecx
+ rep stosl
+ ret
- movb $10, %al
+ .set UART_DATA, 0x3f8
+ .set UART_LSTAT, 0x3fd
+ .set LST_TREG_EMPTY, 0x20
+
+ser_putchar:
+ push %dx
+
+ cmp $10, %al
+ jnz 0f
+ push %ax
+ mov $13, %al
call ser_putchar
+ pop %ax
+
+0: mov %al, %ah
+ # wait until the transmit register is empty
+ mov $UART_LSTAT, %dx
+.Lwait: in %dx, %al
+ and $LST_TREG_EMPTY, %al
+ jz .Lwait
+ mov $UART_DATA, %dx
+ mov %ah, %al
+ out %al, %dx
+
+ pop %dx
+ ret
+
+
+ .code16
+logohack:
+ mov $0x13, %ax
+ int $0x10
# copy palette
mov $logo_pal, %si
mov $0x3c8, %dx
movb %cl, %al
outb %al, %dx
- #### DBG
- call ser_print_num
- mov $58, %al
- call ser_putchar
- mov $32, %al
- call ser_putchar
- xor %eax, %eax
- ####
inc %dx
# red
movb (%si), %al
inc %si
shr $2, %al
outb %al, %dx
- #### DBG
- call ser_print_num
- mov $32, %al
- call ser_putchar
- xor %eax, %eax
- ####
# green
movb (%si), %al
inc %si
shr $2, %al
outb %al, %dx
- #### DBG
- call ser_print_num
- mov $32, %al
- call ser_putchar
- xor %eax, %eax
- ####
# blue
movb (%si), %al
inc %si
shr $2, %al
outb %al, %dx
- #### DBG
- call ser_print_num
- mov $32, %al
- call ser_putchar
- mov $10, %al
- call ser_putchar
- xor %eax, %eax
- ####
add $1, %cl
jnc 0b
jz 0b
jmp .Lframeloop
- cli
- hlt
-
xval: .word 0
yval: .word 0
frameno: .word 0
ret
- # expects number in eax
-ser_print_num:
- # save registers
- pusha
-
- movw $numbuf + 16, %si
- movb $0, (%si)
- mov $10, %ebx
-.Lconvloop:
- xor %edx, %edx
- div %ebx
- add $48, %dl
- dec %si
- mov %dl, (%si)
- cmp $0, %eax
- jnz .Lconvloop
-
- call ser_print_str
-
- # restore regs
- popa
- ret
numbuf: .space 16
projects / bootcensus / commitdiff