Created a target and a library for the Commander X16 prototype computer.

2019-09-27 03:38:51 -04:00
parent 0896deedef
commit 18afc7c703
49 changed files with 2440 additions and 59 deletions
--- a/libsrc/cx16/revers.s
+++ b/libsrc/cx16/revers.s
@@ -0,0 +1,23 @@
+;
+; 2019-09-16, Greg King
+;
+; unsigned char __fastcall__ revers (unsigned char onoff);
+;
+
+        .export         _revers
+
+        .include        "cx16.inc"
+
+.proc   _revers
+        ldy     #$00            ; Assume revers off
+        tax                     ; Test on/off
+        beq     :+              ; Jump if off
+        ldy     #$80            ; Load "on" value
+        ldx     #>$0000         ; Zero high byte of result
+:       lda     RVS             ; Load old value
+        sty     RVS             ; Set new value
+        clc
+        rol     a               ; Convert bit-mask into boolean
+        rol     a
+        rts
+.endproc