initial commit of soft80 implementation

libsrc/c64/soft80_cvline.s

@@ -0,0 +1,28 @@
+;
+; void cvlinexy (unsigned char x, unsigned char y, unsigned char length);
+; void cvline (unsigned char length);
+;
+
+        .export         soft80_cvline, soft80_cvlinexy
+        .import         popa, _gotoxy, putchar, newline ; CHECK/FIX
+        .importzp       tmp1
+
+soft80_cvlinexy:
+        pha                     ; Save the length
+        jsr     popa            ; Get y
+        jsr     _gotoxy         ; Call this one, will pop params
+        pla                     ; Restore the length and run into soft80_cvlinexy
+
+soft80_cvline:
+        cmp     #0              ; Is the length zero?
+        beq     L9              ; Jump if done
+        sta     tmp1
+L1:     lda     #125            ; Vertical bar
+        jsr     putchar         ; Write, no cursor advance
+        jsr     newline         ; Advance cursor to next line
+        dec     tmp1
+        bne     L1
+L9:     rts
+
+
+