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

;-------------------------decnorm routine begins--------------------------+
; from BLUEBOOK OF ASSEMBLY ROUTINES FOR IBM PC & XT.
; page : 99
;
; NAME DECNORM
;
; ROUTINE FOR Normalization of Temporary Decimal Floating Point
;
; FUNCTION: This routine normalizes a temporary decimal floating point
; nuumber.
;
; INPUT: Upon entry DS:DI points to a temporary decimal floating point
; number.
;
; OUTPUT: Upon exit the temporary floating point number is normalized.
;
; REGISTERS USED: AX, CX, and DI are modified.
;
; SEGMENTS REFERENCED: The data segment contains storage for a temporary
; decimal floating point number
;
; ROUTINES CALLED: None
;
; SPECIAL NOTES: Equates are used to shorten address fields.
;
decnorm proc near
;
; check top + 1 digit
cmp dibyte+22,0 ; is it already zero ?
je decnorm2 ; if so exit
;
; round up starting with bottom digit
mov al,[di] ; first digit
add al,al ; double it for roundup
mov ah,0 ; prepare carry
aaa ; adjust for decimal
;
; now shift the rest
mov cx,24 ; for a count of 24
decnorm1:
mov al,[di+1] ; get next digit
add al,ah ; add carry
mov ah,0 ; prepare next carry
aaa ; adjust for decimal
mov [di],al ; put digit into place
inc di ; point to next digit
loop decnorm1
;
inc deexp ; incrememt decimal exponent
;
decnorm2:
;
ret ; return
;
decnorm endp
;-------------------------decnorm routine ends---------------------------+