[stella] cosmic ark stars missile 1

[Andrew Davie]

I don't understand the magic behind cosmic ark stars, but I am using it
successfully for Boulder Dash to give the extra-life shimmer.  However, the
code I use is using missile 0 and I really want to use missile 1.  But when
I change things from missile 0 to missile 1, I no longer get 'stars';  just
'stripes'.  In other words the effect doesn't work.  I'm pretty sure it's to
do with the magic numbers in the following code.  I just don't know what
magic numbers to use for M1 (or for ball).  Can anyone help?

                jsr rndm
                and #7
                clc
                adc #4

                TAY
         ;       STA     WSYNC
.r22             DEY
                BPL     .r22
                STA     RESM0
                LDA     #$70            ;this value is important for the
effect
                STA     HMM0

                STA     WSYNC
                STA     HMOVE
                JSR     Trick2           ;waste 18 cycles and load move
value
                STA     HMM0            ;this is the tricky part


                LDA     #$02            ;turn missile0 on
                sta WSYNC                       ; 3
                STA     ENAM0

                rts

Trick2:          NOP                     ;the tricky subroutine
                NOP
                LDA     #$60
                RTS


The above gives a reasonable random effect for me.  If I change the lda #$60
then it stops working.  If I change to missile 1, it stops working.

Could someone please analyse this and/or suggest the correct values?

Thanks
A