Fix the plot routine to work with the buggy -02 kernal.

git-svn-id: svn://svn.cc65.org/cc65/trunk@4234 b7a2c559-68d2-44c3-8de9-860c34a00d81

diff --git a/libsrc/c64/cputc.s b/libsrc/c64/cputc.s
index cf4275668a7a1d258096f2f1df35311b1c5dce02..6df02b4050a51fae1273cdb629d121967b8cc3b6 100644 (file)
--- a/libsrc/c64/cputc.s
+++ b/libsrc/c64/cputc.s
@@ -1,8 +1,8 @@
 ;
-; Ullrich von Bassewitz, 06.08.1998
+; Ullrich von Bassewitz, 1998-08-06, 2009-09-26
 ;
-; void cputcxy (unsigned char x, unsigned char y, char c);
-; void cputc (char c);
+; void __fastcall__ cputcxy (unsigned char x, unsigned char y, char c);
+; void __fastcall__ cputc (char c);
 ;
 
        .export         _cputcxy, _cputc, cputdirect, putchar
@@ -84,12 +84,20 @@ L11:        ora     #$40
 
 
 
-; Set cursor position, calculate RAM pointers
+; Set cursor position, calculate RAM pointers. Because kernal -02 doesn't
+; update the color RAM pointer, we have to do that manually here.
 
 plot:  ldy     CURS_X
        ldx     CURS_Y
        clc
-       jmp     PLOT            ; Set the new cursor
+               jsr     PLOT            ; Set the new cursor
+        lda     SCREEN_PTR      ; Low byte of color RAM ...
+        sta     CRAM_PTR        ; ... is same as text screen pointer
+        lda     SCREEN_PTR+1    ; While high byte of color RAM
+        and     #$03
+        ora     #$D8            ; ... needs to be adjusted
+        sta     CRAM_PTR+1
+        rts