From c68524fb30716a9ece935f85df5e02e14403b161 Mon Sep 17 00:00:00 2001
From: Ian C <ianc@noddybox.co.uk>
Date: Sat, 25 May 2024 21:37:36 +0100
Subject: Initial test skeleton with flashing colours to try on real VCS

---
 Makefile     |  2 +-
 vcs.asm      | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 vcsdrive.asm | 33 ++++++++++++++++++++++
 3 files changed, 124 insertions(+), 1 deletion(-)
 create mode 100644 vcs.asm

diff --git a/Makefile b/Makefile
index 73f5262..42436ec 100644
--- a/Makefile
+++ b/Makefile
@@ -20,5 +20,5 @@
 # Makefile
 #
 
-vcsdrive.bin: vcsdrive.asm
+vcsdrive.bin: vcsdrive.asm vcs.asm
 	casm vcsdrive.asm
diff --git a/vcs.asm b/vcs.asm
new file mode 100644
index 0000000..e716442
--- /dev/null
+++ b/vcs.asm
@@ -0,0 +1,90 @@
+; vcsdrive - Simple Atari VCS driving game
+;
+; Copyright (C) 2024  Ian Cowburn (ianc@noddybox.demon.co.uk)
+;
+; This program is free software: you can redistribute it and/or modify
+; it under the terms of the GNU General Public License as published by
+; the Free Software Foundation, either version 3 of the License, or
+; (at your option) any later version.
+;
+; This program is distributed in the hope that it will be useful,
+; but WITHOUT ANY WARRANTY; without even the implied warranty of
+; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+; GNU General Public License for more details.
+;
+; You should have received a copy of the GNU General Public License
+; along with this program.  If not, see <http://www.gnu.org/licenses/>.
+;
+; -------------------------------------------------------------------------
+;
+; Atari VCS definitions
+;
+VSYNC	equ	$00
+VBLANK	equ	$01
+WSYNC	equ	$02
+RSYNC	equ	$03
+NUSIZ0	equ	$04
+NUSIZ1	equ	$05
+COLUP0	equ	$06
+COLUP1	equ	$07
+COLUPF	equ	$08
+COLUBK	equ	$09
+CTRLPF	equ	$0A
+REFP0	equ	$0B
+REFP1	equ	$0C
+PF0	equ	$0D
+PF1	equ	$0E
+PF2	equ	$0F
+RESP0	equ	$10
+RESP1	equ	$11
+RESM0	equ	$12
+RESM1	equ	$13
+RESBL	equ	$14
+AUDC0	equ	$15
+AUDC1	equ	$16
+AUDF0	equ	$17
+AUDF1	equ	$18
+AUDV0	equ	$19
+AUDV1	equ	$1A
+GRP0	equ	$1B
+GRP1	equ	$1C
+ENAM0	equ	$1D
+ENAM1	equ	$1E
+ENABL	equ	$1F
+HMP0	equ	$20
+HMP1	equ	$21
+HMM0	equ	$22
+HMM1	equ	$23
+HMBL	equ	$24
+VDELP0	equ	$25
+VDELP1	equ	$26
+VDELBL	equ	$27
+RESMP0	equ	$28
+RESMP1	equ	$29
+HMOVE	equ	$2A
+HMCLR	equ	$2B
+CXCLR	equ	$2C
+CXM0P	equ	$30
+CXM1P	equ	$31
+CXP0FB	equ	$32
+CXP1FB	equ	$33
+CXM0FB	equ	$34
+CXM1FB	equ	$35
+CXBLPF	equ	$36
+CXPPMM	equ	$37
+INPT0	equ	$38
+INPT1	equ	$39
+INPT2	equ	$3A
+INPT3	equ	$3B
+INPT4	equ	$3C
+INPT5	equ	$3D
+SWCHA	equ	$0280
+SWACNT	equ	$0281
+SWCHB	equ	$0282
+SWBCNT	equ	$0283
+INTIM	equ	$0284
+INSTAT	equ	$0285
+TIM1T	equ	$0294
+TIM8T	equ	$0295
+TIM64T	equ	$0296
+T1024T	equ	$0297
diff --git a/vcsdrive.asm b/vcsdrive.asm
index dd84ef1..c271652 100644
--- a/vcsdrive.asm
+++ b/vcsdrive.asm
@@ -19,3 +19,36 @@
 ;
 ; Code
 ;
+        processor       6502
+        option          output-file,vcsdrive.bin
+
+        include         vcs.asm
+
+        org             $f000
+
+        ; Set up stack pointer
+start:
+        sei
+        cld
+        ldx             #$ff
+        txs
+
+        ; Initialise page zero
+        lda             #0
+.zero:
+        sta             $0,x
+        dex
+        bne             zero
+
+        ; Set background
+        lda             #$3e
+        clc
+.loop:
+        sta             COLUBK
+        adc             #1
+        jmp             loop
+
+        ; Set start adresses and pad ROM
+        org             $fffc
+        word            start
+        word            start
-- 
cgit v1.2.3