; Title - hi-res
; By    - Adam Trionfo
; REV.    1.2 - June 5, 2004
;              - This program NO longer seems to even
;                run under the MESS emulator...
;         1.1 - Nov. 30, 2003
;               - Made compatible with HVGLIB.H
;         1.0 - March 22, 2002
; 
; This program could not have been written without using
; Mike White's "Astro BASIC 4x2 Multicart Loader" and
; and the "Nutting Manual" as a reference.
;
;  
; About this Program
; ------------------ 
;
; Displays, in hi-res, 16 pixels starting at $4000
; (the top-left side of the screen).
; The colors are repeated twice (two whites together,
; two blacks together, etc) so that they can be
; disguised from each other.  This program works on
; the Astrocade emulator (it doesn't ANYMORE!),
; but not a real Astrocade.
; This program only displays in the top-left 1/4 of the
; screen (since the Astrocade only has 4K of RAM and
; this isn't really "true" hi-res [there's not 16K]).
;
; Assembling this Program
; -----------------------
;    This file will assemble with ZMAC 1.3 (a little
; known, freely distributable Z-80 assembler (with C
; source), that has a 25-year history.  ZMAC can be
; compiled under just about any O.S. in existence, so
; try it out. 
;  
; To assemble Z-80 source code using ZMAC:
;  
; zmac -i -m -o <outfile> -x <listfile> <filename>
; 
; For example, to assemble this Astrocade Z-80 program:
;    
; zmac -i -m -o hi-res.bin -x hi-res.lst hi-res.asm

INCLUDE "HVGLIB.H"        ; Home Video Game Library Header

        ORG    FIRSTC     ; First byte of Cartridge
        JP     PRGST

; Program Start
PRGST:  DI                ; Disable interrupts

        LD      A,$01     ; Set system into high-res
        OUT    (CONCM),A

        SYSTEM (INTPC)    ; Start System Interpreter 

        DO     (SETOUT)   ; Set Display Ports
        DB     176D       ; Vertical Blanking Line 
        DB     1D         ; Left/Right Color Boundary 
        DB     $18        ; Interrupt Mode 

        DO     (COLSET)   ; Set Color Registers
        DW     COLTAB     ; Color Table

        DO     (FILL)     ; Screen Fill
        DW     $4000      ; Destination
        DW     4000D      ; Bytes to move
        DB     $00        ; Fill with zeros

        DO     (MOVE)     ; Move Bytes
        DW     $4000      ; Destination
        DW     4D         ; Bytes to move (two)
        DW     TOMOVE     ; Source Address

        EXIT              ; Exit System Interpreter

        EI                ; Enable interrupts 

LOOP:   NOP               ; Endless loop
        JP     LOOP       ; End of program

; Program Data

; Color Table #1

COLTAB: DB     $04        ; Color 3 Left 
        DB     $05        ; Color 2 Left
        DB     $06        ; Color 1 Left 
        DB     $07        ; Color 0 Left - White
        DB     $00        ; Color 3 Right - Black
        DB     $01        ; Color 2 Right 
        DB     $02        ; Color 1 Right 
        DB     $03        ; Color 0 Right

; Bytes to move
TOMOVE: DB     00000101B  ; Four pixels (0,1,2,3)
        DB     10101111B  ; Four pixels (0,1,2,3)
        DB     00000101B  ; Four pixels (0,1,2,3)
        DB     10101111B  ; Four pixels (0,1,2,3)

; End of Program