用 子程序 一个字符串中的小写转为大写
assume cs :code
data segment
db "I am a boooy!!",0
data ends
code segment
start:
mov ax,data
mov ds,ax
mov si,0
mov dx,0
call s
ok: mov ax,4c00h
int 21h
s: push ax
push si
push dx
mov ah,[si]
cmp ah,0
je ok
cmp ah,'a'
jb esc1
cmp ah,'z'
ja esc1
inc dx
and ah,11011111B
mov [si],ah
inc si
jmp s
pop dx
pop si
pop ax
ret
esc1: inc si
jmp s
pop dx
pop si
pop ax
ret
code ends
end start
在一个字符串中找等于 8 的字符个数(注意 类型的 转换)
assume cs:code
data segment
db 8,11,8,1,8,5,63,38
data ends
code segment
start: mov ax,data
mov ds,ax
mov si,0
mov cx,8
mov ax,0
s:
cmp byte ptr [si],8
jna ok
inc ax
ok:
inc si
loop s
mov ax,4c00h
int 21h
code ends
end start
待续