-; Break vector
-BRKVec = $03F0
-; Goto Dos
-RESTOR = $03D0
+;-----------------------------------------------------------------------------
+; Zero page stuff
-; Soft switches
-;
-; write to USEROM to enable apple rom C000-CFFF
-USEROM = $C007
-; 80 column card switches
-C80ON = $C00C
-C80OFF = $C00D
-RD80COL = $C01F
-PG2OFF = $C054
-PG2ON = $C055
-RDPAGE2 = $C01C
-
-; Text routines
MIN_X = $20
MAX_X = $21
MIN_Y = $22
CV = $25
BASL = $28
TEXTTYP = $32
+RNDL = $4E ; Random value, low byte
+RNDH = $4F ; Random value, high byte
MEMSIZE = $73 ; Highest free RAM location
-HOME = $FC58
-VTABZ = $FC24
-COUT = $FDED
+
+;-----------------------------------------------------------------------------
+; Vectors
+
+BRKVec = $03F0 ; Break vector
+RESTOR = $03D0 ; Goto Dos
+
+;-----------------------------------------------------------------------------
+; Hardware
+
+; Soft switches
+;
+; Write to USEROM to enable apple rom C000-CFFF
+USEROM = $C007
+
+; 80 column card switches
+C80ON = $C00C
+C80OFF = $C00D
+RD80COL = $C01F
+PG2OFF = $C054
+PG2ON = $C055
+RDPAGE2 = $C01C
; Keyboard entries
RDKEY = $FD0C
KEY_STROBE = $C000
; Game controller
-OPEN_APPLE = $C061
-CLOSED_APPLE = $C062
+OPEN_APPLE = $C061
+CLOSED_APPLE = $C062
+
+;-----------------------------------------------------------------------------
+; ROM routines
+
+; Text output and helpers
+HOME = $FC58
+VTABZ = $FC24
+COUT = $FDED
-;Graphics entry points, by cbmnut (applenut??) cbmnut@hushmail.com
-WHITE = $01 ;white for $1c, I think...
+; Graphics entry points, by cbmnut (applenut??) cbmnut@hushmail.com
+WHITE = $01 ; White for $1c, I think...
-COLOR = $1C ;Current plot color
+COLOR = $1C ; Current plot color
-HGR2 = $F3D8 ;Initialize and clear hi-res page 2.
+HGR2 = $F3D8 ; Initialize and clear hi-res page 2.
-HGR = $F3E2 ;Initialize and clear hi-res page 1.
+HGR = $F3E2 ; Initialize and clear hi-res page 1.
-HCLR = $F3F2 ;Clear the current hi-res screen to black.
+HCLR = $F3F2 ; Clear the current hi-res screen to black.
-BKGND = $F3F6 ;Clear the current hi-res screen to the
- ;last plotted color (from ($1C).
+BKGND = $F3F6 ; Clear the current hi-res screen to the
+ ; last plotted color (from ($1C).
-HPOSN = $F411 ;Positions the hi-res cursor without
- ;plotting a point.
- ;Enter with (A) = Y-coordinate, and
- ;(Y,X) = X-coordinate.
+HPOSN = $F411 ; Positions the hi-res cursor without
+ ; plotting a point.
+ ; Enter with (A) = Y-coordinate, and
+ ; (Y,X) = X-coordinate.
-HPLOT = $F457 ;Calls HPOSN and tries to plot a dot at
- ;the cursor's position. If you are
- ;trying to plot a non-white color at
- ;a complementary color position, no
- ;dot will be plotted.
+HPLOT = $F457 ; Calls HPOSN and tries to plot a dot at
+ ; the cursor's position. If you are
+ ; trying to plot a non-white color at
+ ; a complementary color position, no
+ ; dot will be plotted.
-HLIN = $F53A ;Draws a line from the last plotted
- ;point or line destination to:
- ;(X,A) = X-coordinate, and
- ;(Y) = Y-coordinate.
+HLIN = $F53A ; Draws a line from the last plotted
+ ; point or line destination to:
+ ; (X,A) = X-coordinate, and
+ ; (Y) = Y-coordinate.
-HFIND = $F5CB ;Converts the hi-res coursor's position
- ;back to X- and Y-coordinates; stores
- ;X-coordinate at $E0,E1 and Y-coordinate
- ;at $E2.
+HFIND = $F5CB ; Converts the hi-res coursor's position
+ ; back to X- and Y-coordinates; stores
+ ; X-coordinate at $E0,E1 and Y-coordinate
+ ; at $E2.
-DRAW = $F601 ;Draws a shape. Enter with (Y,X) = the
- ;address of the shape table, and (A) =
- ;the rotation factor. Uses the current
- ;color.
+DRAW = $F601 ; Draws a shape. Enter with (Y,X) = the
+ ; address of the shape table, and (A) =
+ ; the rotation factor. Uses the current
+ ; color.
-XDRAW = $F65D ;Draws a shape by inverting the existing
- ;color of the dots the shape draws over.
- ;Same entry parameters as DRAW.
+XDRAW = $F65D ; Draws a shape by inverting the existing
+ ; color of the dots the shape draws over.
+ ; Same entry parameters as DRAW.
-SETHCOL = $F6EC ;Set the hi-res color to (X), where (X)
- ;must be between 0 and 7.
+SETHCOL = $F6EC ; Set the hi-res color to (X), where (X)
+ ; must be between 0 and 7.