Merge pull request #257 from petersobolev/patch-1

Create assembler_6809vectrex.asm

a/assembler_6809vectrex.asm

@@ -0,0 +1,33 @@
+
+; Hello World for Vectrex computer with 6809 CPU
+; by Frog ( http://frog.enlight.ru )
+; 24 March 2016
+
+;***************************************************************************
+                org     0
+
+; this header required to identify ROM by Vectrex hardware (only year allowed to change)
+                db      "g GCE 2016", $80       ; 'g' is copyright sign
+                dw      $F600                   ; music from the rom (no music)
+                db      $FC, $30, 33, -$2a      ; height, width, rel y, rel x for app title
+                db      "HELLO WORLD", $80      ; app title, ending with $80
+                db      0                       ; end of header
+
+; main loop (required to redraw vectors on CRT screen)
+loop:
+
+; recalibrate CRT, reset beam to 0,0 (center of the screen)
+                jsr     $f192                   ; Wait_Recal subroutine in ROM
+
+                ldu     #helloworld             ; string address
+                lda     #10                     ; Y
+                ldb     #-45                    ; X
+
+                jsr     $f37a                   ; Print_Str_d subroutine in ROM
+
+                bra     loop
+
+; Text data ($80 - end of line)
+
+helloworld:     db      'HELLO WORLD!',$80
+