Draw a floor which moves.

colourgo.xcodeproj/project.pbxproj

@@ -19,6 +19,10 @@
 		9DFD77D31F1F9C2500639A48 /* V2Make.scpt */ = {isa = PBXFileReference; lastKnownFileType = file; name = V2Make.scpt; path = make/V2Make.scpt; sourceTree = "<group>"; };
 		9DFD77D91F1FA47900639A48 /* main.c */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.c; path = main.c; sourceTree = "<group>"; };
 		9DFD77DB1F1FA4A400639A48 /* game.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = game.h; sourceTree = "<group>"; };
+		9DFD77DC1F1FB69600639A48 /* vbl.s */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.asm; path = vbl.s; sourceTree = "<group>"; };
+		9DFD77DD1F1FB69600639A48 /* vbl.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = vbl.h; sourceTree = "<group>"; };
+		9DFD77DE1F1FB69600639A48 /* machine.c */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.c; path = machine.c; sourceTree = "<group>"; };
+		9DFD77DF1F1FB69600639A48 /* machine.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = machine.h; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXGroup section */
@@ -35,6 +39,10 @@
 				9DFD77C91F1F9C2500639A48 /* game.s */,
 				9DFD77DB1F1FA4A400639A48 /* game.h */,
 				9DFD77D91F1FA47900639A48 /* main.c */,
+				9DFD77DC1F1FB69600639A48 /* vbl.s */,
+				9DFD77DD1F1FB69600639A48 /* vbl.h */,
+				9DFD77DE1F1FB69600639A48 /* machine.c */,
+				9DFD77DF1F1FB69600639A48 /* machine.h */,
 				9DFD77CA1F1F9C2500639A48 /* Makefile */,
 				9DFD77CB1F1F9C2500639A48 /* make */,
 			);

colourgo/game.s

@@ -9,6 +9,8 @@
 
     .export _game
 
+    .import _vblWait
+
     .include "apple2.inc"
 
 
@@ -218,27 +220,102 @@ LINE191 = LINE190 + 1024
 
 .CODE
 
-_game:
+.proc _game
 
 ; Set up hires screen
-
     jsr clearScreen
     lda TXTCLR
     lda MIXCLR
     lda HIRES
     lda LOWSCR
 
-    
+
-wait:
+    ldy #150
+    jsr drawLine
+    ldy #155
+    jsr drawLine
+
+    ldx #0
+@L1:
+    jsr _vblWait
+    ldy #151
+    jsr drawGrid
+    ldy #152
+    jsr drawGrid
+    ldy #153
+    jsr drawGrid
+    ldy #154
+    jsr drawGrid
+    inx
+    cpx #7
+    bne @L2
+    ldx #0
+
+@L2:
     lda KEYBOARD
-    bpl wait
+    bpl @L1
     lda STROBE
 
     lda TXTSET
 
     rts
 
-clearScreen:
+.endproc
+
+
+.proc drawLine
+    lda loAddrs,y
+    sta ZPADDR
+    lda page1HiAddrs,y
+    sta ZPADDR+1
+
+    ldy #0
+@L1:
+    lda #$55
+    sta (ZPADDR),y
+    iny
+    lda #$2a
+    sta (ZPADDR),y
+    iny
+    cpy #MAXXBYTE
+    bne @L1
+
+    rts
+.endproc
+
+
+.proc drawGrid
+    lda loAddrs,y
+    sta ZPADDR
+    lda page1HiAddrs,y
+    sta ZPADDR+1
+
+    lda violetEvenGrid,x
+    sta evenVal
+    lda violetOddGrid,x
+    sta oddVal
+
+    ldy #0
+@L1:
+    lda evenVal
+    sta (ZPADDR),y
+    iny
+    lda oddVal
+    sta (ZPADDR),y
+    iny
+    cpy #MAXXBYTE
+    bne @L1
+
+    rts
+
+; Locals
+evenVal: .BYTE $00
+oddVal:  .BYTE $00
+
+.endproc
+
+
+.proc clearScreen
     ldx #0
     ldy #0
 
@@ -260,6 +337,8 @@ clearScreen:
     bne @L1
 
     rts
+.endproc
+
 
 .DATA
 
@@ -340,3 +419,10 @@ page2HiAddrs:
 .HIBYTES LINE168+$2000, LINE169+$2000, LINE170+$2000, LINE171+$2000, LINE172+$2000, LINE173+$2000, LINE174+$2000, LINE175+$2000
 .HIBYTES LINE176+$2000, LINE177+$2000, LINE178+$2000, LINE179+$2000, LINE180+$2000, LINE181+$2000, LINE182+$2000, LINE183+$2000
 .HIBYTES LINE184+$2000, LINE185+$2000, LINE186+$2000, LINE187+$2000, LINE188+$2000, LINE189+$2000, LINE190+$2000, LINE191+$2000
+
+violetEvenGrid:
+    .BYTE $00, $00, $00, $40, $10, $04, $01
+
+violetOddGrid:
+    .BYTE $20, $08, $02, $00, $00, $00, $00
+

colourgo/machine.c

@@ -0,0 +1,103 @@
+//
+//  machine.c
+//  colourgo
+//
+//  Created by Jeremy Rand on 2017-07-19.
+//  Copyright © 2017 Jeremy Rand. All rights reserved.
+//
+
+
+#include <apple2.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+#include "machine.h"
+#include "vbl.h"
+
+
+// Typedefs
+typedef enum {
+    GS_SPEED_SLOW,
+    GS_SPEED_FAST
+} tMachineGSSpeed;
+
+
+// Globals
+
+static tMachineGSSpeed gOldSpeed = GS_SPEED_SLOW;
+
+
+// Implementation
+
+
+static bool machineIs2c(void)
+{
+    switch (get_ostype()) {
+        case APPLE_IIC:
+        case APPLE_IIC35:
+        case APPLE_IICEXP:
+        case APPLE_IICREV:
+        case APPLE_IICPLUS:
+            return true;
+    }
+    
+    return false;
+}
+
+
+static bool machineIs2GS(void)
+{
+    switch (get_ostype()) {
+        case APPLE_IIGS:
+        case APPLE_IIGS1:
+        case APPLE_IIGS3:
+            return true;
+    }
+    
+    return false;
+}
+
+
+static tMachineGSSpeed setGSSpeed(tMachineGSSpeed newSpeed)
+{
+    uint8_t *speedRegister = (uint8_t *)0xc036;
+    uint8_t value = *speedRegister;
+    tMachineGSSpeed oldSpeed;
+    
+    if ((value & 0x80) != 0)
+        oldSpeed = GS_SPEED_FAST;
+    else
+        oldSpeed = GS_SPEED_SLOW;
+    
+    if (oldSpeed != newSpeed) {
+        if (newSpeed == GS_SPEED_FAST) {
+            value |= 0x80;
+        } else {
+            value &= 0x7f;
+        }
+        *speedRegister = value;
+    }
+    
+    return oldSpeed;
+}
+
+
+void initMachine(void)
+{
+    gVblWait = vblWaitNon2c;
+    
+    if (machineIs2c()) {
+        gVblWait = vblWait2c;
+    } else if (machineIs2GS()) {
+        vblInit2gs();
+        gOldSpeed = setGSSpeed(GS_SPEED_SLOW);
+    }
+}
+
+
+void uninitMachine(void)
+{
+    if (machineIs2GS()) {
+        setGSSpeed(gOldSpeed);
+    }
+}

colourgo/machine.h

@@ -0,0 +1,19 @@
+//
+//  machine.h
+//  colourgo
+//
+//  Created by Jeremy Rand on 2017-07-19.
+//  Copyright © 2017 Jeremy Rand. All rights reserved.
+//
+
+#ifndef __colourgo__machine__
+#define __colourgo__machine__
+
+
+// API
+
+extern void initMachine(void);
+extern void uninitMachine(void);
+
+
+#endif /* defined(__colourgo__machine__) */

colourgo/main.c

@@ -9,10 +9,13 @@
 #include <stdio.h>
 
 #include "game.h"
+#include "machine.h"
 
 
 int main(void)
 {
+    initMachine();
     game();
+    uninitMachine();
     return 0;
 }

colourgo/vbl.h

@@ -0,0 +1,32 @@
+//
+//  vbl.h
+//  colourgo
+//
+//  Created by Jeremy Rand on 2017-07-19.
+//  Copyright © 2017 Jeremy Rand. All rights reserved.
+//
+
+#ifndef __colourgo__vbl__
+#define __colourgo__vbl__
+
+
+// Typedefs
+
+typedef void (*tVblWaitFunction)(void);
+
+
+// Globals
+
+extern tVblWaitFunction gVblWait;
+
+// API
+
+extern void __fastcall__ vblInit2gs(void);
+extern void __fastcall__ vblWait(void);
+extern void __fastcall__ vblWaitNon2c(void);
+extern void __fastcall__ vblWait2c(void);
+
+extern void __fastcall__ vblIRQCallback(void);
+
+
+#endif /* defined(__colourgo__vbl__) */

colourgo/vbl.s

@@ -0,0 +1,75 @@
+;
+;  vbl.s
+;  colourgo
+;
+;  Created by Jeremy Rand on 2017-07-19.
+;  Copyright © 2017 Jeremy Rand. All rights reserved.
+;
+
+
+
+    .export _vblWait, _vblWaitNon2c, _vblWait2c, _vblInit2gs
+    .export _gVblWait
+    .interruptor _vblIRQCallback
+
+
+    .include "apple2.inc"
+
+
+RDVBLBAR      :=  $C019
+
+
+.proc _vblWait
+    jmp (_gVblWait)
+.endproc
+
+.proc _vblInit2gs
+    lda #$fe
+    sta compType
+.endproc
+
+
+.proc _vblWaitNon2c
+    lda   compType
+@L1:
+    cmp   RDVBLBAR
+    bpl   @L1
+@L2:
+    cmp   RDVBLBAR
+    bmi   @L2
+
+    rts
+.endproc
+
+
+.proc _vblIRQCallback
+    pha
+    lda #$0
+    sta vbl2cByte
+    pla
+    rts
+.endproc
+
+
+.proc _vblWait2c
+    lda #$ff
+    sta vbl2cByte
+
+@L1:
+    lda vbl2cByte
+    bne @L1
+
+    rts
+.endproc
+
+
+.data
+
+_gVblWait:
+    .BYTE   $0, $0
+
+compType:
+    .BYTE   $7e
+
+vbl2cByte:
+    .BYTE   $00