汇编语言 实现一个数字的平方

Posted 2021-06-30 ʚVVcatɞ

; 参数 ax = 3456
; 返回值 dx = 高 16位  ax = 低16位
assume cs:code, ds:data, ss:stack

data segment
		db 128 dup(0)
data ends

stack segment stack
			db 128 dup(0)
stack ends

code segment 
		start: mov ax, stack
				mov ss, ax
				mov sp, 128
				
				call cpy_new_int7CH
				call set_new_int7CH
				
				mov ax, 3456
				int 7CH
				
				mov ax, 4C00H
				int 21H
;====================================================
new_int7CH:     mul ax
				iret
				
new_int7CH_end: nop

set_new_int7CH:
				mov bx, 0
				mov es, bx
				
				cli
				mov word ptr es:[7CH * 4], 7E00H
				mov word ptr es:[7CH * 4 + 2], 0
				sti
				ret
				
;========================================================
cpy_new_int7CH:		
				mov bx, cs
				mov ds, bx
				mov si, OFFSET new_int7CH
				
				mov bx, 0
				mov es, bx
				mov di, 7E00H
				
				mov cx, OFFSET new_int7CH_end - new_int7CH
				cld
				rep movsb
				ret
				
code ends

end start