phs_bitta_0.asm

bit_to_a_0:
        bta_0:
        cmp ch,9
        jg bta_1
        add ch,'0'
        jmp bta_fin
                bta_1:
        sub ch,10
        add ch,'a'
                bta_fin:
        ret

phs_execution.asm

execution:
        mov bh,0x7f
        mov [hex_string+0x7c00],bh
        call print_hex_string
        jmp infloop
times 510-($-$$) db 0
dw 0xaa55

phs_hextoteletype.asm

jmp execution
hex_string:
        db '0x00',0
infloop:
        jmp $
print_string:
        mov ah,0x0e
        add bx,0x7c00
                        ps_l:
        mov al,[bx]
        cmp al,0
        je psfin
        int 0x10
        inc bx
        jmp ps_l
                        psfin:
        ret
print_hex_string:
        mov [hex_string+0x7c00],bh
        mov bl,0
                        phs_B:
        cmp bh,16
        jng phs_A
        sub bh,16
        inc bl
        jmp phs_B
                        phs_A:
        ;; Umrechnen in A oder 0
        mov ch,bl
        call bit_to_a_0
        mov bl,ch
        mov [hex_string+0x7c00+2],bl
        mov ch,bh
        call bit_to_a_0
        mov bh,ch
        mov [hex_string+0x7c00+3],bh
        mov bh,'0'
        mov [hex_string+0x7c00],bh
        mov bx,hex_string
        call print_string
        ret
bit_to_a_0:
        bta_0:
        cmp ch,9
        jg bta_1
        add ch,'0'
        jmp bta_fin
                bta_1:
        sub ch,10
        add ch,'a'
                bta_fin:
        ret
execution:
        mov bh,0x7f
        mov [hex_string+0x7c00],bh
        call print_hex_string
        jmp infloop
times 510-($-$$) db 0
dw 0xaa55

phs_print_hex_string.asm

print_hex_string:
        mov [hex_string+0x7c00],bh
        mov bl,0
                        phs_B:
        cmp bh,16
        jng phs_A
        sub bh,16
        inc bl
        jmp phs_B
                        phs_A:
        mov ch,bl
        call bit_to_a_0
        mov bl,ch
        mov [hex_string+0x7c00+2],bl
        mov ch,bh
        call bit_to_a_0
        mov bh,ch
        mov [hex_string+0x7c00+3],bh
        mov bh,'0'
        mov [hex_string+0x7c00],bh
        mov bx,hex_string
        call print_string
        ret

phs_print_hex_string2.asm

print_hex_string:
        mov [hex_string+0x7c00],bh
        mov bl,0
        cmp bh,0
        jg phs_B
        add bl,8
        add bh,128
                        phs_B:
        cmp bh,16
        jng phs_A
        sub bh,16
        inc bl
        jmp phs_B
                        phs_A:
        mov ch,bl
        call bit_to_a_0
        mov bl,ch
        mov [hex_string+0x7c00+2],bl
        mov ch,bh
        call bit_to_a_0
        mov bh,ch
        mov [hex_string+0x7c00+3],bh
        mov bh,'0'
        mov [hex_string+0x7c00],bh
        mov bx,hex_string
        call print_string
        ret

phs_qemu.txt

Booting from Hard Disk...
                          0x7f  
Booting from Hard Disk...
                          0x8f