8086组装-更好的数据存储/操作？

我正在为一个课堂项目工作，并且按项目要求工作，尽管我想知道是否有一种更好的方法来实现一些事情。我因在另一个项目中不必要的“移动”而停靠了几点。这是问题1。

“如果-否则（34分）：编写一个程序，要求用户输入一个数字。如果该数字小于5，则应声明，然后将其加5并将其存储在变量中；如果该数字大于5，则将其声明为0，然后从中减去5并将其存储在变量中；如果数字为5，则将其加3并声明为3并将其存储在变量中。”

org 100h   
mov dx, offset start   ;move start of string address 'start' into dx
mov ah, 09h   
int 21h                ;print the string stored at DS:DX
mov ah, 01h            ;function for getting keyboard input
int 21h
sub al, 30h            ;subtract 30h to store our number as hexadecimal
mov bl, al             ;copying data to BL as the following commands manipulate the data
                       ;at AL. 
cmp bl, 5              ;BL = AL
jz ifZero              ;jump to ifZero if BL = 5
jl ifLess              ;jump to isLess if BL < 5
jg ifGreater           ;jump to ifGreater if BL > 5

ifZero:                ;direct console output function
mov ah, 06h            
mov dl, 0Ah
int 21h
mov dl, 0Dh
int 21h                ;print newline and character return
add bl, 03h            ;add 3 to BL, BL = 8
mov temp, bl           
mov dx, offset eq      ;move start of string address 'eq' into dx
mov ah, 09h
int 21h                ;print string
jmp exit               ;unconditional jump to end program

ifLess:                ;direct console output function
mov ah, 06h
mov dl, 0aH
int 21h
mov dl, 0Dh
int 21h                ;print newline and character return
add bl, 05h            ;add 5 to BL
mov temp, bl           
mov dx, offset less    ;move start of string address 'less' into dx
mov ah, 09h
int 21h                ;print string
jmp exit               ;unconditional jump to end program

ifGreater: 
mov ah, 06h            
mov dl, 0ah
int 21h
mov dl, 0dh
int 21h                ;print newline and character return
sub bl, 05h            ;subtract 5 from BL
mov temp, bl
mov dx, offset great   ;move starting address of string 'great' into dx
mov ah, 09h
int 21h                ;print string
jmp exit               ;unconditional jump to end program


exit:
ret

temp db ? 
start db "Please enter a number: $"
less db "Less than 5... adding 5 $"
great db "Greater than 5... subtracting 5 $"
eq db "Equal to 5... adding 3 $"

在这种情况下，是否不需要'mov bl，al'？通过反汇编程序运行，表明AL中的数据在执行这些命令中的大多数后都会发生变化。这应该发生吗？有更好的方法吗？

问题3：计数器控制的循环。该程序将要求用户输入一个字符，然后将其显示带有标签的字符五次。例如：输入一个字符：A您输入了：A

org 100h
mov cx, 05h             ;counter controlled loop, start as 5

LabelLoop:
mov dx, offset prompt   ;move string offset to dx
mov ah, 09h             ;function for printing string from dx
int 21h
mov ah, 01h             ;function to read character from keyboard
int 21h    
mov bl, al              ;preserving character read by copying to BL
                        ;as register data for AL will be changing
                        ;due to various functions
mov ah, 06h             ;function for direct console output
mov dl, 0ah
int 21h
mov dl, 0dh             ;these just make the text appear on a new
                    ;line
int 21h
mov dx, offset output   ;move the memory offset of output to dx
mov ah, 09h             ;printing another string
int 21h
mov ah, 02h             ;function to write a character to console
                        ;gets the value from DL
mov dl, bl                  ;so we copy BL to DL and print it
int 21h
jmp newLine             ;we unconditionally jump to the newLine
                        ;label and print a new line for the program
                        ;to run again

newLine:
mov ah, 06h
mov dl, 0ah
int 21h
mov dl, 0dh
int 21h
loop LabelLoop         ;we jump to LabelLoop and CX = CX - 1

mov dx, offset goodbye
mov ah, 09h
int 21h

ret

prompt db 'Enter a character: $'
output db 'You entered: $'
goodbye db 'Good bye!$'

因此，对于这些问题，我有更好的方法吗？键盘输入存储在AL中，但是每次我对AH执行mov功能时，无论是字符串打印还是字符打印，寄存器值都会更改。为了避免变量（因为它不是要求的一部分）或将其分配到内存（我们还没有学到），我将数据移到了另一个寄存器中。这对于两个程序来说都是不必要的“移动”吗？

编辑：我意识到后AL = DL

mov ah, 06h
mov dl, 0ah
int 21h       ;AL = DL after execution