Add basic support for ORIC Atmos

git-svn-id: svn://svn.cc65.org/cc65/trunk@2046 b7a2c559-68d2-44c3-8de9-860c34a00d81
2003-04-13 22:12:09 +00:00
parent d48f341bba
commit 9f547a5a4d
21 changed files with 1001 additions and 5 deletions
--- a/libsrc/atmos/clrscr.s
+++ b/libsrc/atmos/clrscr.s
@@ -0,0 +1,47 @@
+;
+; Ullrich von Bassewitz, 2003-04-13
+;
+
+	.export	  	_clrscr
+        .importzp       ptr2
+
+	.include  	"atmos.inc"
+
+; ------------------------------------------------------------------------
+; void __fastcall__ clrscr (void);
+
+.proc	_clrscr
+
+; Set the cursor to top left cursor position
+
+        ldy     #$00
+        sty     CURS_X
+        sty     CURS_Y
+
+; Set ptr2 to the screen position (left upper border)
+
+        lda     #<SCREEN
+        sta     ptr2
+        lda     #>SCREEN
+        sta     ptr2+1
+
+; Clear full pages. Y is still zero
+
+        ldx     #>(28*40)
+        lda     #' '
+@L1:    sta     (ptr2),y
+        iny                     ; Bump low byte of address
+        bne     @L1
+        inc     ptr2+1          ; Bump high byte of address
+        dex
+        bne     @L1
+
+; Clear the remaining page
+
+@L2:    sta     (ptr2),y
+        iny
+        cpy     #<(28*40)
+        bne     @L2
+        rts
+
+.endproc