汇编11章的作业语言

assume cs:codesg

datasg segment

db "Beginner's All-purpose Symbolic Instruction Code.",0

datasg ends

codesg segment

start:

mov ax,datasg

mov ds,ax

mov si,0

call letterc

mov ax,4c00h

int 21h

letterc:;==小写字母转为大写字母==

push si

push ax

mov ax,0

push ax

popf

s0:

mov al,[si]

cmp al,0

je quit

cmp al,61h

jb s1

cmp al,07aH

ja s1

sub al,20h

mov [si],al

s1:

inc si

jmp s0

quit:

pop ax

pop si

ret

codesg ends

end start