Category : Assembly Language Source Code
Archive   : ASM-SUBR.ZIP
Filename : DEC16IN

;-------------------------dec16in routine begins--------------------------+
; from BLUEBOOK OF ASSEMBLY ROUTINES FOR IBM PC & XT.
; page : 57
;
; NAME DEC16IN
; ROUTINE FOR conversion from ASCII decimal to 16-bit Binary
;
; FUNCTION: This routine accepts an decimal number from the standard input
; device and converts it to internal 16-bit binary form.
; INPUT: The individual digits of the decimal number are received in ASCII
; through a call to a standard I/O routine. The valid digits are 0 - 9.
; An ASCII code other than for a valid digit will terminate the routine.
;
; OUTPUT: A 16-bit binary number is returned in the DX register.
; REGISTERS USED: Only DX is modified. It returns the result.
; SEGMENTS REFERENCED: None
; ROUTINES CALLED: STDIN
; SPECIAL NOTES: None
;
; ROUTINE TO CONVERT FROM ASCII decimal TO INTERNAL 16-BIT BINARY
;
dec16in proc far
;
push cx ; save registers
push ax
;
mov dx,0 ; initialize DX
;
dec16in1:
call stdin ; a digit comes in in AL
sub al,30h ; reduce from ASCII
jl dec16in2 ; check if too low
cmp al,9
jg dec16in2 ; check if too high
cbw ; convert to word
;
push ax ; save digit
mov ax,dx ;
mov cx,10 ; decimal power of 10
mul cx ; multiply
mov dx,ax ; store result in DX
pop axl ; restore digit
add dx,ax ; add in digit
jmp dec16in1
;
dec16in2:
;
pop ax ; restore registers
pop cx
ret ; return
;
dec16in endp
;-------------------------dec16in routine ends---------------------------+