Category : Assembly Language Source Code
Archive   : ASM_SUBR.ZIP
Filename : FPTNORM

;-------------------------fptnorm routine begins--------------------------+
; from BLUEBOOK OF ASSEMBLY ROUTINES FOR IBM PC & XT.
; page : 84
;
; NAME FPTNORM
; ROUTINE FOR NORMALIZATION OF TEMPORARY FLOATING POINT
;
; FUNCTION: This routine normalizes temporary binary floating point
; numbers that have too large a mantissa.
;
; INPUT: Upon entry DS:DI points to a temporary binary floating point
; number whose mantissa is too large
;
; OUTPUT: Upon exit DS:DI points to a normalized temporary binary floating
; point number.
;
; REGISTERS USED: No registers are modified. DI must point to the number
;
; SEGMENTS REFERENCED: The data segment must contain the temporary
; floating point number.
;
; ROUTINES CALLED: None
; SPECIAL NOTES: Equates are used to shorten address fields. This is a
; near procedure needed by FPIN.
;
; ROUTINE TO NORMALIZE TEMP FLO-ATING POINT NUMBERS THAT HAVE TOO LARGE
; A MANTISSA.
;
fptnorm proc near
;
cmp diword+8,100h ; test if too high
jl fptnorm1 ; exit if low enough
sar diword+8,1 ; shift right all bytes
rcr diword+6,1 ; carry on
rcr diword+4,1
rcr diword+2,1
rcr diword+0,1
inc diword+11 ; increment exponent
jmp fptnorm
;
fptnorm1:
ret ; return
;
fptnorm endp
;-------------------------fptnorm routine ends---------------------------+