*\ RND.ASM                                             From: AMIGA.3955
*  :ts=8 bk=0
* Yet Another random number generator.  By Leo Schwab.
* Based on an idea posted on the USENET (Thanks, Sam Dicker!)
* For the MetaComCo assembler
*
* Calling convention:
*  long rnd (range);
*  long range;
*
* Assembling:
*  df1:c/assem rnd.asm -o rnd.o
* 
* 8606.30
*/

                section code
                xdef    _rnd

_rnd            lea     rndseed,a0      Get address of seed
                move.l  4(sp),d1        Get range argument
                tst.l   d1
                ble.s   setseed         Go reset seed


                move.l  (a0),d0         Get seed
                ADD.L   D0,D0
                BHI.S   over
                EORI.L  #$1D872B41,D0
over
                move.l  d0,(a0)         Save new seed
                andi.l  #$ffff,d0       Coerce into word
                andi.l  #$ffff,d1
                divu    d1,d0           Divide by range
                swap    d0               and get remainder (modulus)
                ext.l   d0
                rts

setseed         neg.l   d1              Probably don't need this
                move.l  d1,(a0)
                rts

                section data
rndseed         dc.l    0
                end