atari: split color.s into bordercolor.s and bgcolor.s

2019-04-02 19:10:52 +02:00
parent 0576fe51e7
commit edd596b2a4
3 changed files with 23 additions and 14 deletions
--- a/libsrc/atari/bgcolor.s
+++ b/libsrc/atari/bgcolor.s
@@ -0,0 +1,22 @@
+;
+; Christian Groessler, 02-Apr-2019
+;
+
+        .export         _bgcolor
+
+        .include        "atari.inc"
+
+
+_bgcolor:
+        ldx     COLOR2  ; get old value
+        sta     COLOR2  ; set new value
+        and     #$0e
+        cmp     #8
+        bcs     bright
+        lda     #$0e
+        .byte   $2c     ; bit opcode, eats the next 2 bytes
+bright: lda     #0
+        sta     COLOR1
+        txa
+        ldx     #0      ; fix X
+        rts