atari5200: implement bgcolor() and textcolor()

Includes some other small fixes/cleanups.

testcode/lib/atari5200/hello.c

@@ -0,0 +1,101 @@
+/*
+** Fancy hello world program using cc65.
+**
+** Ullrich von Bassewitz (ullrich@von-bassewitz.de)
+**
+** TEST version for atari5200 conio, using all four colors
+*/
+
+
+
+#include <stdlib.h>
+#include <string.h>
+#include <conio.h>
+#include <joystick.h>
+
+
+
+/*****************************************************************************/
+/*                                   Data                                    */
+/*****************************************************************************/
+
+
+
+static const char Text [] = "Hello world!";
+
+
+
+/*****************************************************************************/
+/*                                   Code                                    */
+/*****************************************************************************/
+
+
+
+int main (void)
+{
+    unsigned char XSize, YSize;
+    unsigned char PosY;
+
+    /* Set screen colors */
+    (void) textcolor (COLOR_WHITE);
+    (void) bordercolor (COLOR_BLACK);
+    (void) bgcolor (COLOR_BLACK);
+
+    /* Clear the screen, put cursor in upper left corner */
+    clrscr ();
+
+    /* Ask for the screen size */
+    screensize (&XSize, &YSize);
+
+    /* Draw a border around the screen */
+
+    /* Top line */
+    cputc (CH_ULCORNER);
+    chline (XSize - 2);
+    cputc (CH_URCORNER);
+
+    /* Vertical line, left side */
+    cvlinexy (0, 1, YSize - 2);
+
+    /* Bottom line */
+    cputc (CH_LLCORNER);
+    chline (XSize - 2);
+    cputc (CH_LRCORNER);
+
+    /* Vertical line, right side */
+    cvlinexy (XSize - 1, 1, YSize - 2);
+
+    /* Write the greeting in the mid of the screen */
+    gotoxy ((XSize - strlen (Text)) / 2, YSize / 2);
+    cprintf ("%s", Text);
+
+    PosY = wherey () + 1;
+    textcolor (0); /* switch to color #0 */
+    cputsxy(3, PosY++, "COLOR 0");
+    textcolor (1); /* switch to color #1 */
+    cputsxy(3, PosY++, "COLOR 1");
+    textcolor (2); /* switch to color #2 */
+    cputsxy(3, PosY++, "COLOR 2");
+    textcolor (3); /* switch to color #3 */
+    cputsxy(3, PosY, "COLOR 3");
+
+#if defined(__NES__) || defined(__PCE__) || defined(__GAMATE__) || defined(__ATARI5200__)
+
+    /* Wait for the user to press a button */
+    joy_install (joy_static_stddrv);
+    while (!joy_read (JOY_1)) ;
+    joy_uninstall ();
+
+#else
+
+    /* Wait for the user to press a key */
+    cgetc ();
+
+#endif
+
+    /* Clear the screen again */
+    clrscr ();
+
+    /* Done */
+    return EXIT_SUCCESS;
+}