王爽<汇编语言> 第十一章 实验十一

assume cs:codesg,ds:datasg



datasg segment

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

datasg ends



codesg segment

letterc:push bp

mov bp,sp

push bx

push ax

mov bx,ss:4h[bp]



lt_find:mov al,ds:[bx]

cmp al,0h

je lt_end

cmp al,61h

jb lt_next

cmp al,7ah

ja lt_next

sub al,20h

mov ds:[bx],al

lt_next:inc bx

jmp lt_find



lt_end:pop ax

pop bx

pop bp

ret 2h

start:mov ax,datasg

mov ds,ax



mov ax,0h

push ax

call letterc



mov ax,4c00h

int 21h

codesg ends



end start