--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/level2/modules/joydrv_joy.asm	Thu Apr 04 16:34:12 2002 +0000
@@ -0,0 +1,229 @@
+********************************************************************
+* JoyDrv - Joystick Driver for CoCo 3 Hi-Res Mouse
+*
+* $Id$
+*
+* Ed.    Comments                                       Who YY/MM/DD
+* ------------------------------------------------------------------
+* 6      L2 Upgrade distribution version
+*        Annotations by Robert Gault                    RG  98/10/09
+
+         nam   JoyDrv
+         ttl   Joystick Driver for CoCo 3 Hi-Res Mouse
+
+* Disassembled 98/09/09 09:07:45 by Disasm v1.6 (C) 1988 by RML
+
+         ifp1  
+         use   defsfile
+         endc  
+
+tylg     set   Systm+Objct
+atrv     set   ReEnt+rev
+rev      set   $01
+edition  set   6
+
+         mod   eom,name,tylg,atrv,start,size
+size     equ   .
+
+name     fcs   /JoyDrv/
+         fcb   edition
+
+start    lbra  Init       setup for special button state & clear buttons
+         lbra  Term       clear button but don't change special flag
+         lbra  SSMsBtn    read and process button values
+         lbra  SSMsXY    read joystick values; with processing
+         lbra  SSJoyBtn  clear keyboard input and return raw button info
+
+SSJoyXY  pshs  y,x,b,a    read joystick values
+         pshs  x,b,a
+         ldx   #PIA0Base  point to PIA#1
+         lda   <$23,x     read sound enable state?
+         ldb   <$20,x     read 6-bit DAC
+         pshs  b,a        save current states
+         anda  #%11110111 clear sound enable
+         sta   <$23,x     set switch
+         lda   $01,x      read MUX SEL#1
+         ldb   $03,x      read MUX SEL#2
+         pshs  b,a        save current state
+         orb   #$08       set SEL#2
+         lda   $08,s      read ?what?
+         anda  #$02       keep only left or right joystick
+         bne   L0047      if left then don't
+         andb  #%11110111 clear SEL#2
+L0047    stb   $03,x      enable SEL#2 value
+         leay  <L0097,pcr point to high res routine
+         ldb   $0D,s      flag for high/low res
+         bne   L0054
+         leay  >L010F,pcr point to low res routine
+L0054    lda   ,s
+         ora   #$08       set MUX SEL#1
+         jsr   ,y         read pot
+         tst   $0D,s      here the same byte seems to be used for x/y flag??
+         beq   L0060
+         bsr   L00DB      convert from width to height value
+L0060    std   $06,s      return joystick value
+         lda   ,s         now read the other direction
+         anda  #$F7       flip the MUX SEL#1 bit
+         jsr   ,y         read the second pot
+         std   $04,s      save the other value
+         puls  b,a
+         sta   $01,x
+         stb   $03,x
+         puls  b,a
+         stb   <$20,x     reset the DAC and sound selector
+         sta   <$23,x
+         puls  y,x
+         lda   ,s         flag for double button?
+         cmpa  #$01
+         bne   L0094
+         ldb   #$80       minimum flag
+         lda   $05,s
+         bne   L008B
+         cmpx  #32        minimum joystick value
+         bcc   L0092
+L008B    cmpx  #320       maximum joystick value
+         bcc   L0092      if less than don't change flag
+         ldb   #$C0       maximum flag
+L0092    stb   ,u         save max/min flag value
+L0094    leas  $06,s
+         rts   
+L0097    pshs  cc         high res routine
+         sta   $01,x      select x/y pot
+         lda   #$FF       full DAC value
+         sta   <$20,x     store in DAC to charge capacitor
+         lda   #$5A       timing loop; wait for voltage to settle
+L00A2    deca  
+         bne   L00A2      wait
+         ldd   #$0329
+         pshs  a
+         lda   #$02
+         orcc  #IntMasks  kill interrupts
+         sta   <$20,x     clear DAC; mask RS-232; start cap. discharge
+L00B1    lda   ,x         test comparator
+         bmi   L00C0
+         decb             counter  
+         bne   L00B1      loop until state change
+         dec   ,s         3 -> 0
+         bpl   L00B1      loop again
+         puls  a
+         bra   L00D6      branch to maximum value
+L00C0    puls  a
+         decb  
+         pshs  b,a
+         ldd   #640
+         subd  ,s++       convert from 640 -> 0 to 0 -> 640
+         bcc   L00D0
+         clra             minimum value is $00  
+         clrb  
+         puls  pc,cc
+L00D0    cmpd  #639
+         bcs   L00D9
+L00D6    ldd   #639       maximum value
+L00D9    puls  pc,cc
+* This routine converts a pot value from width (640) to height (192) to match
+* possible screen values; ie. value divided by 3.33
+L00DB    pshs  a
+         lda   #$09
+         pshs  a
+         lda   #$03
+         mul   
+         pshs  b,a
+         lda   $03,s
+         ldb   #$03
+         mul   
+         exg   b,a
+         addd  ,s++
+L00EF    clr   $01,s
+         cmpa  #$0A
+         bcs   L00F9
+         inc   $01,s
+         suba  #$0A
+L00F9    lsr   $01,s
+         rolb  
+         rola  
+         dec   ,s
+         bne   L00EF
+         cmpb  #$BF
+         beq   L010B
+         cmpa  #$0A
+         bcs   L010B
+         addb  #$01
+L010B    clra  
+         leas  $02,s
+         rts   
+* Low res binary tree search for joystick value   
+L010F    sta   $01,x      set MUX SEL#1
+         lda   #$7F       DAC value
+         ldb   #$40
+         bra   L0122
+L0117    lsrb             reset DAC offset value 
+         cmpb  #$01
+         bhi   L0122
+         lsra  
+         lsra  
+         tfr   a,b
+         clra  
+         rts              return with voltage   
+L0122    pshs  b
+         sta   <$20,x     set DAC
+         tst   ,x         test comparator
+         bpl   L012F
+         adda  ,s+        adjust binary tree search
+         bra   L0117
+L012F    suba  ,s+        adjust binary tree search
+         bra   L0117
+
+SSMsXY   leay  ,y         get flag??
+         lbne  SSJoyXY    go read joystick pots
+         lbsr  SSJoyXY    go read joystick pots and then convert values
+         tfr   x,d        multiply regX by 10 and regY by 3
+         lda   #$0A
+         mul   
+         tfr   d,x
+         cmpx  #630
+         bcs   L014B
+         ldx   #634       maximum limit on regX
+*	may be an error and could be 639
+L014B    tfr   y,d
+         lda   #$03
+         mul   
+         tfr   d,y
+         rts   
+
+Init     ldb   #$80
+         stb   ,u
+
+Term     clr   $01,u
+         rts   
+
+SSJoyBtn ldx   #PIA0Base  PIA#1 base address
+         clrb  
+         comb  
+         stb   $02,x      clear PIA#1 key strobe lines
+         ldb   ,x         read data lines
+         comb             only buttons and comparator valid
+         andb  #$0F       only buttons; 0=off 1=on
+         rts   
+
+SSMsBtn  bsr   SSJoyBtn
+         tfr   b,a
+         anda  #%11111010 regA=left buttons; should be $0A not $FA
+         pshs  a          save left button values
+         andb  #$05       regB=right buttons
+         orb   $01,u      ORB with previous state??
+         leax  <L0187,pcr point to sequential switch table possibilities
+         lda   b,x
+         anda  #%00001010 keep only left values
+         sta   $01,u      save for change test
+         ldb   b,x        repeat
+         andb  #%10000101 keep flag and right values
+         bpl   L0184
+         ldb   ,u         previous min/max state
+L0184    orb   ,s+        ORB with current left values and pop stack
+         rts   
+L0187    fcb   $00,$03,$00,$03,$08,$06,$02,$06,$80,$02,$00,$02,$08,$06,$0a,$06
+
+         emod  
+eom      equ   *
+         end   
+