atari5200 update: simple conio "hello world" works now

2014-04-25 03:02:44 +02:00
parent ec417c0dc5
commit 92b32d7d0e
7 changed files with 252 additions and 14 deletions
--- a/libsrc/atari5200/mul20.s
+++ b/libsrc/atari5200/mul20.s
@@ -0,0 +1,33 @@
+;
+; Christian Groessler, April 2014
+;
+; mul20
+; multiplies A by 20 and returns result in AX
+; uses tmp4
+
+        .importzp       tmp4
+        .export         mul20,loc_tmp
+
+.proc   mul20
+
+        ldx     #0
+        stx     tmp4
+        sta     loc_tmp
+        asl     a
+        rol     tmp4
+        asl     a
+        rol     tmp4            ; val * 4
+        adc     loc_tmp
+        bcc     L1
+        inc     tmp4            ; val * 5
+L1:     asl     a
+        rol     tmp4            ; val * 10
+        asl     a
+        rol     tmp4            ; val * 20
+        ldx     tmp4
+        rts
+
+.endproc
+
+        .bss
+loc_tmp:.res    1