hos2.s

用于汇编领域的,运用于OS的MAIN函数.基于硬件基础的源代码

.code16
.globl _start
_start:
   movw $0x1000, %ax
   movw %ax, %ds
   movw %ax, %es
   call screen_setup
   movw $greet, %si
   call print
   lp: jmp lp

screen_setup:
   movw $0xb800, %ax
   movw %ax, %es
   xorw %di, %di
   movw $0x1f20, %ax
   movw $0x800, %cx
   cld
   rep stosw
   movb $0x02, %ah
   xorw %dx, %dx
   xorw %bx, %bx
   int $0x10
   ret

print:
   movb (%si), %al
   cmpb $0x00, %al
   je print_end
   movb $0x0e, %ah
   xorw %bx, %bx
   int $0x10
   incw %si
   jmp print
print_end:
   movb $0x0e, %ah
   movb $0x0d, %al
   xorw %bx, %bx
   int $0x10
   movb $0x0a, %al
   int $0x10
   ret
greet:
   .asciz "Hello from hos2"