How to decimal adjust 4 digit addition in assembly 8085

Question

I am trying to do a decimal adjust after addition creating a 4 digit decimal. I see that the daa command exists but that only adjusts the al while I need the entire ax adjusted to from hex to decimal.

For Example:

mov ax, 9876h
mov bx, 5432h
add ax, bx

would result in ECA8 in the ax register. The answer after the conversion I want would be something like 5308 in the ax register with a carry flag specifying the one before the 5 in the full answer (15308)

DAA only affects al instead of ax , is there some other command to do this or an easy way to do such a thing? (I'm also looking for an idea for subtraction as well since DAS also only affects al )

Answer 1

Since the original example is for the 8086, I'll show an answer with that instruction set. The same principle would apply to the 8085. There isn't an equivalent to the daa instruction that operates on a two-byte value. So, you'll have to split up your operation:

    mov al, 76h
    add al, 32h
    daa
    mov bl, al
    jnc skip
    mov bh, 1
skip:
    mov al, 98h
    add al, 54h
    daa
    add bh, al

And CF will be set if there's a 5th digit carry over.