Move an 8 bit register to a 16 bit memory location, how?

Question

I have problem moving 8 bit register to a 16 bit register.

What i'm trying to do is to divide a number repeatedly by 10 til it gets lower than 10, and, within each division time, i try to move out the remained part of the division out from AH register, add 48 to it, then i could have its Ascii code , then i try to show the digit i got , on screen.

 Num1 DW 255
 DIVISION :
        CMP NUM1,10
            Jl DIVEND
            
        MOV AX,10
        DIV NUM1
        MOV NUM1,AL    ;*  Operand types do not match
    
        
        ADD AH,48
        MOV DL,AH; 
        MOV AH,02H
        INT 21H
        
    JMP DIVISION

but , when im trying to assemble it , it says , Operand types do not match on the line indicated by *.

im using turbo assembler V4.1 ...

Answer 1

Did you mean that?

mov bx, Offset Num1 
mov [bx], al

The error you get is because you declare a word but adress it as a byte. If you did Num1 db it also works.

Tested with TASM 4.1

Answer 2

As for the more general question in the title: you use movzx (move zero extend) for unsigned values and movsx (move sign extend) for signed values.