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boote.s
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boote.s
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.code16
movw $0x07c0, %ax
movw %ax, %ds
xorw %ax, %ax
movw $0x7c00, %sp
callw clear_screen
pushw $0
callw set_cursor
addw $2, %sp
pushw $message
callw puts
addw $2, %sp
jmp .
# 目的: 打印字符串
#
# 输入:
# 参数1 字符串在数据段的索引
#
# 输出: 无
puts:
pushw %bp
movw %sp, %bp
pushw %bx
pushw %si
movw 4(%bp), %si
1:
cmpb $0, (%si)
je .ps_exit
movb (%si), %bl
andw $0x00ff, %bx
orw $0x0a00, %bx
pushw %bx
callw putc
addw $2, %sp
incw %si
jmp 1b
.ps_exit:
popw %si
popw %bx
movw %bp, %sp
popw %bp
retw
# 目的: 打印字符
#
# 输入:
# 参数1 字符(可包含显示属性)
#
# 输出: 无
putc:
pushw %bp
movw %sp, %bp
pushw %cx
pushw %es
pushw %si
movw 4(%bp), %cx
movw $0xb800, %ax
movw %ax, %es
callw get_cursor
movw %ax, %si
shlw $1, %si
movw %cx, %es:(%si)
incw %ax
pushw %ax
callw set_cursor
addw $2, %sp
popw %si
popw %es
popw %cx
movw %bp, %sp
popw %bp
retw
# 目的: 获取光标位置
#
# 输入: 无
#
# 输出: 光标当前位置, 保存在 %ax 中
get_cursor:
movw $0x3d4, %dx
movb $0xe, %al
outb %al, %dx
movw $0x3d5, %dx
inb %dx, %al
movb %al, %ah
movw $0x3d4, %dx
movb $0xf, %al
outb %al, %dx
movw $0x3d5, %dx
inb %dx, %al
retw
# 目的: 设置光标位置
#
# 输入:
# 参数1 光标所在位置
#
# 输出: 无
set_cursor:
pushw %bp
movw %sp, %bp
movw $0x3d4, %dx
movb $0xe, %al
outb %al, %dx
movw $0x3d5, %dx
movb 5(%bp), %al
outb %al, %dx
movw $0x3d4, %dx
movb $0xf, %al
outb %al, %dx
movw $0x3d5, %dx
movb 4(%bp), %al
outb %al, %dx
movw %bp, %sp
popw %bp
retw
# 目的: 清空屏幕
#
# 输入: 无
#
# 输出: 无
clear_screen:
pushw %bp
movw %sp, %bp
pushw %es
pushw %si
pushw %cx
movw $0xb800, %cx
movw %cx, %es
movw $2000, %cx
xorw %si, %si
1:
movw $' ' | 0x0700, %es:(%si)
addw $2, %si
loop 1b
popw %cx
popw %si
popw %es
movw %bp, %sp
popw %bp
retw
message:
.asciz "laoli ai ni!"
.org 510
.word 0xAA55