Assembly sum with different size numbers

Can I sum different bits (8 bit with 1开发者_运维问答6 bit) number in assembly?

For example;

 sums proc near
 mov ax,0280h
 mov bh,30h
 mov ch,20h
 adc ax,bh
 adc ax,ch
 ret 
 sums endp

This code gives an error; "operant types dont match"

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Sure. Just load the 8-bit value into a register and sign-extend or zero-extend it. Then add.

---

Of course.

mov ax,33h
mov cx,1133h
add ax,cx

---

This is a shot in the dark, so correct me if I'm wrong (NASM - AT & T syntax)

 .section .text

 .globl _start
_start:
 movl $0, %eax
 mov $0x280, %ax
 movl $0, %ebx
 movl $0, %ecx
 mov $0x30, %bh
 mov $0x20, %ch
 add %bx, %ax
 add %cx, %ax

 movl %eax, %ebx    # store the result in %ebx
 movl $1, %eax      # syscall for exit()
 int $0x80

If you are on Linux, after running this application on the console, execute:

echo $?

to print the return code of the app, which is actually the sum we did before (and stored in %ebx).

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Change

mov bh,30h
mov ch,20h
adc ax,bh
adc ax,ch

to

mov bx,30h
mov cx,20h
adc ax,bx
adc ax,cx