.code16
.section .boot2,"a"
- .extern ser_putchar
+ # make sure any BIOS call didn't re-enable interrupts
+ cli
+
+ # just in case we were loaded from floppy, turn all floppy motors off
+ call motor_off
mov $0x13, %ax
int $0x10
+ # 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
+
movb $10, %al
call ser_putchar
+ call clearscr
+
+ mov $hello, %esi
+ call putstr
+
+ # enable A20 line
+ call enable_a20
+
+ call logohack
+
+ cli
+ hlt
+
+hello: .asciz "Switched to 32bit\n"
+
+ .align 4
+gdt_lim: .word 23
+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
+
+
+ .align 8
+idt: .space 104
+ # trap gate 13: general protection fault
+ .short prot_fault
+ .short 0x8
+ # type: trap, present, default
+ .short 0x8f00
+ .short 0
+
+gpf_msg: .asciz "GP fault "
+
+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"
+
+enable_a20:
+ call test_a20
+ jnc a20done
+ call enable_a20_kbd
+ call test_a20
+ jnc a20done
+ call enable_a20_fast
+ call test_a20
+ jnc a20done
+ # keep trying ... we can't do anything useful without A20 anyway
+ jmp enable_a20
+a20done:
+ 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
+
+ # enable A20 line through port 0x92 (fast A20)
+enable_a20_fast:
+ mov $ena20_fast_msg, %esi
+ call putstr
+
+ in $0x92, %al
+ or $2, %al
+ out %al, $0x92
+ ret
+
+ena20_fast_msg: .asciz "Attempting fast A20 enable\n"
+
+
+ # enable A20 line through the keyboard controller
+ .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
+
+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
+
+ena20_kbd_msg: .asciz "Attempting KBD A20 enable\n"
+
+ # 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
+convloop:
+ xor %edx, %edx
+ div %ebx
+ add $48, %dl
+ dec %esi
+ mov %dl, (%esi)
+ cmp $0, %eax
+ jnz convloop
+
+ 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
+
+ .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
+wait: in %dx, %al
+ and $LST_TREG_EMPTY, %al
+ jz wait
+ mov $UART_DATA, %dx
+ mov %ah, %al
+ out %al, %dx
+
+ pop %dx
+ ret
+
+
+motor_off:
+ mov $0x3f2, %dx
+ in %dx, %al
+ and $0xf0, %al
+ out %al, %dx
+ ret
+
+logohack:
# copy palette
- mov $logo_pal, %si
+ mov $logo_pal, %esi
xor %cl, %cl
0: xor %eax, %eax
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
+ movb (%esi), %al
+ inc %esi
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
+ movb (%esi), %al
+ inc %esi
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
+ movb (%esi), %al
+ inc %esi
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
# copy pixels
- pushw $0xa000
- pop %es
- mov $logo_pix, %eax
- shr $4, %eax
- #mov %ax, %ds
- mov %ax, %gs
- #mov $16000, %ecx
- #rep movsl
-
- mov $sintab, %eax
- shr $4, %eax
- mov %ax, %fs
-
-.Lframeloop:
- xor %di, %di
-
- movw $0, yval
-.Lyloop:
- movw $0, xval
-.Lxloop:
- # calc src scanline address -> bx
- mov yval, %bx
- shl $2, %bx
- add frameno, %bx
- xor %bh, %bh
- mov %fs:(%bx), %cl
- xor %ch, %ch
- shr $5, %cx
-
- mov yval, %ax
- add %cx, %ax
+ mov $sintab, %ebp
+ mov $logo_pix, %esi
+frameloop:
+ mov $0xa0000, %edi
+ movl $0, yval
+yloop:
+ movl $0, xval
+xloop:
+ # calc src scanline address -> ebx
+ xor %ecx, %ecx
+ mov yval, %ebx
+ shl $2, %ebx
+ add frameno, %ebx
+ and $0xff, %ebx
+ mov (%ebp, %ebx), %cl
+ shr $5, %ecx
+
+ mov yval, %eax
+ add %ecx, %eax
# bounds check
- cmp $200, %ax
+ cmp $200, %eax
jl 0f
- mov $199, %ax
-
-0: mov %ax, %bx
- shl $8, %ax
- shl $6, %bx
- add %ax, %bx
-
- # calc src x offset -> si
- mov xval, %ax
- shl $2, %ax
- add frameno, %ax
- xor %ah, %ah
- mov %ax, %si
- mov %fs:(%si), %cl
- xor %ch, %ch
- shr $5, %cx
-
- mov xval, %ax
- add %cx, %ax
+ mov $199, %eax
+
+0: mov %eax, %ebx
+ shl $8, %eax
+ shl $6, %ebx
+ add %eax, %ebx
+
+ # calc src x offset -> eax
+ xor %ecx, %ecx
+ mov xval, %eax
+ shl $2, %eax
+ add frameno, %eax
+ and $0xff, %eax
+ mov (%ebp, %eax), %cl
+ shr $5, %ecx
+
+ mov xval, %eax
+ add %ecx, %eax
# bounds check
- cmp $320, %ax
+ cmp $320, %eax
jl 0f
- mov $319, %ax
-
-0: mov %ax, %si
+ mov $319, %eax
- mov %gs:(%bx, %si), %al
+0: add %eax, %ebx
+ mov (%ebx, %esi), %al
- mov %al, %es:(%di)
- inc %di
+ mov %al, (%edi)
+ inc %edi
- incw xval
- cmpw $320, xval
- jnz .Lxloop
+ incl xval
+ cmpl $320, xval
+ jnz xloop
- incw yval
- cmpw $200, yval
- jnz .Lyloop
+ incl yval
+ cmpl $200, yval
+ jnz yloop
- incw frameno
+ incl frameno
# wait vsync
mov $0x3da, %dx
0: in %dx, %al
and $8, %al
jz 0b
- jmp .Lframeloop
-
- cli
- hlt
-
-xval: .word 0
-yval: .word 0
-frameno: .word 0
-
- # expects string pointer in ds:si
-ser_print_str:
- pusha
-
-0: mov (%si), %al
- cmp $0, %al
- jz .Lend
- call ser_putchar
- inc %si
- jmp 0b
-
-.Lend: popa
- ret
-
+ jmp frameloop
- # 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
+xval: .long 0
+yval: .long 0
+frameno: .long 0
numbuf: .space 16
projects / bootcensus / blobdiff