;Reads a character to AL

readch:

;Store the initial registers
push bx
push ax

;Read a keypress
mov ah, 0x0
int 0x16

;Check for non-printing characters
cmp al, 0x1f
jle readch
cmp al, 0x7f
je readch

;Print the character
mov ah, 0xe
int 0x10

;Load the initial registers
pop bx
mov ah, bh
pop bx

ret