Category : Assembly Language Source Code
Archive   : ASM-SUBR.ZIP
Filename : I162BCD

;-------------------------i162bcd routine begins--------------------------+
; from BLUEBOOK OF ASSEMBLY ROUTINES FOR IBM PC & XT.
; page : 70
;
; NAME I162BCD
; ROUTINE FOR CONVERSION FROM 16-BIT BINARY TO BCD
;
; FUNCTION: This routine converts from internal 16-bit binary numbers to
; numbers stored in internal BCD format
;
; INPUT: Upon entry a 16-bit binary number is in the DX register
;
; OUTPUT: Upon return a 36-digit number is stored in BCD form in an 18-
; byte buffer in the data segment called BCDBUFF
;
; REGISTERS USED: No registers are modified. DX is used for input.
;
; SEGMENTS REFERENCED: DATAS is a data segment which contains the buffer
; BDCBUFF
;
; ROUTINES CALLED: None
; SPECIAL NOTES: None
;
; ROUTIINE TO CONVERT FROM INTERNAL 16-BIT BINARY TO INTERNAL BCD
;
i162bcd proc far
;
push ds ; save registers
push si
push dx
push cx
push ax
;
; set up the data segment
mov ax,datas ; point to data segment
mov ds,ax
;
; a binary number is in DX
;
; clear bcd buffer
lea di,bcdbuff ; point to buffer
mov al,0 ; zero byte
mov cx,18 ; bcdbuff size
;
i162bcd1:
mov [di],al ; clear byte
inc di ; point to next one
loop i162bcd1
;
; put the digits in a buffer
lea di,bcdbuff ; point to bcdbuff
;
i162bcd2
mov ax,dx ; numerator
mov dx,0 ; clear upper half
mov cx,10 ; divisor of 10
div cx ; divide
xchg ax,dx ; get quotient
mov bl,al ; save digit
;
mov ax,dx ; numerator
mov dx,0 ; clear upper half
mov cx,10 ; divisor of 10
div cx ; divide
xchg ax,dx ; get quotient
;
mov cl,4 ; for a count of 4
rol al,cl ; rotate byte
and al,0Fh ; just the digit
or al,bl ; combine digits
;
mov [di],al ; put in buffer
inc di ; next byte
cmp dx,0 ; done ?
jnz i162bcd2 ; nope
;
pop ax ; yes, done...restore registers
pop cx
pop dx
pop di
pop ds
ret ; return
;
i162bcd endp
;-------------------------i162bcd routine ends---------------------------+