From 083ed795ec22cc51c3ee0f06bc0daf07c41fe266 Mon Sep 17 00:00:00 2001
From: Philip Zembrod <pzembrod@gmail.com>
Date: Tue, 18 Jun 2024 19:39:35 +0200
Subject: [PATCH] Port taskdemo.fth to the X16, directly writing to VERA's
 VRAM.

---
 6502/C64/src/taskdemo-x16.fth | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 6502/C64/src/taskdemo-x16.fth

diff --git a/6502/C64/src/taskdemo-x16.fth b/6502/C64/src/taskdemo-x16.fth
new file mode 100644
index 0000000..4d1682c
--- /dev/null
+++ b/6502/C64/src/taskdemo-x16.fth
@@ -0,0 +1,33 @@
+\ Taskdemo for X16
+
+: taskmark ; \needs cbm>scr : cbm>scr ;
+
+\ This method of writing directly into the X16's screen memory
+\ is a bit hacky and relies on the default settings that the
+\ Kernal uses for text mode.
+: scrstart  ( -- adr)  $b000 ;
+: ctrl@  ( -- b )  $9f25 c@ ;
+: addr-sel@ ( -- 0/1 )  ctrl@  1 and ;
+: datax!  ( c -- )  $9f23 addr-sel@ +  c! ;
+: addrx-l/m!  ( u -- )  $9f20 ! ;
+: scr!  ( scrcode vram-addr -- )
+  addrx-l/m!  datax! ;
+
+Variable counter  counter off
+
+$100 $100 Task Background
+
+: >count  ( n -)
+ Background 1 pass
+ counter !
+ BEGIN  counter @  -1 counter +! ?dup
+ WHILE  pause 0 <# #s #>   dup >r
+  0 DO  pause  dup I + c@  cbm>scr
+        scrstart I 2* +  scr!  LOOP  drop
+  bl  r> 2* scrstart +  scr!
+ REPEAT
+ BEGIN stop REPEAT ; \ stop's forever
+: wait  Background sleep ;
+: go    Background wake ;
+
+multitask       $1000 >count  page