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

;-------------------------random routine begins--------------------------+
; from BLUEBOOK OF ASSEMBLY ROUTINES FOR IBM PC & XT.
; page : 175
;
; NAME RANDOM
; ROUTINE FOR PSEUDO-RANDOM NUMBER GENERATOR
;
; FUNCTION: This routine generates pseudo-random numbers bewteen0 and 1.
; The numbers are stored in 16-bit binary fixed-point notation with the
; binary point on the extreme left.
; INPUT: Upon entry the variabl,e SEED contains a seed value.
; OUTPUT: Upon exit the seed is updated and the CX register contains a
; pseudo-random number.
; REGISTERS USED: Only CX is modified.
; SEGMENTS REFERENCED: pon entry the data segment contains the variable
; SEED.
; ROUTINES CALLED: None
; SPECIAL NOTES: None
;
random proc far
;
mov cx,seed ;get the seed
add cx,9248h ; add random pattern
ror cx,1 ; rotate
ror cx,1 ; three
ror cx,1 ; times.
mov seed,cx ; put it back
ret ; return
;
random endp
;-------------------------random routine ends---------------------------+