/*
- * Minimalistic overlay demo program.
- *
- * 2009-10-02, Oliver Schmidt (ol.sc@web.de)
- *
- */
+** Minimalistic overlay demo program.
+**
+** Shows how to load overlay files from disk.
+**
+** 2009-10-02, Oliver Schmidt (ol.sc@web.de)
+**
+*/
#include <stdio.h>
-#include <conio.h>
+#include <cc65.h>
+#ifndef __CBM__
#include <fcntl.h>
#include <unistd.h>
+#else
+#include <cbm.h>
+#include <device.h>
+#endif
-extern void _OVERLAY1_LOAD__, _OVERLAY1_SIZE__;
-extern void _OVERLAY2_LOAD__, _OVERLAY2_SIZE__;
-extern void _OVERLAY3_LOAD__, _OVERLAY3_SIZE__;
+extern void _OVERLAY1_LOAD__[], _OVERLAY1_SIZE__[];
+extern void _OVERLAY2_LOAD__[], _OVERLAY2_SIZE__[];
+extern void _OVERLAY3_LOAD__[], _OVERLAY3_SIZE__[];
/* Functions resident in an overlay can call back functions resident in the
- * main program at any time without any precautions. The function log() is
- * an example for such a function resident in the main program.
- */
+** main program at any time without any precautions. The function log() is
+** an example for such a function resident in the main program.
+*/
void log (char *msg)
{
printf ("Log: %s\n", msg);
/* In a real-world overlay program one would probably not use a #pragma but
- * rather place the all the code of certain source files into the overlay by
- * compiling them with --code-name OVERLAY1.
- */
+** rather place all the code of certain source files into the overlay by
+** compiling them with --code-name OVERLAY1.
+*/
#pragma code-name (push, "OVERLAY1");
void foo (void)
{
/* Functions resident in an overlay can access all program variables and
- * constants at any time without any precautions because those are never
- * placed in overlays. The string constant below is an example for such
- * a constant resident in the main program.
- */
+ ** constants at any time without any precautions because those are never
+ ** placed in overlays. The string constant below is an example for such
+ ** a constant resident in the main program.
+ */
log ("Calling main from overlay 1");
}
unsigned char loadfile (char *name, void *addr, void *size)
{
+#ifndef __CBM__
+
int file = open (name, O_RDONLY);
if (file == -1) {
log ("Opening overlay file failed");
return 0;
}
-
read (file, addr, (unsigned) size);
close (file);
+
+#else
+
+ /* Avoid compiler warnings about unused parameters. */
+ (void) addr; (void) size;
+ if (cbm_load (name, getcurrentdevice (), NULL) == 0) {
+ log ("Loading overlay file failed");
+ return 0;
+ }
+
+#endif
return 1;
}
log ("Calling overlay 1 from main");
/* The symbols _OVERLAY1_LOAD__ and _OVERLAY1_SIZE__ were generated by the
- * linker. They contain the overlay area address and size specific to a
- * certain program.
- */
- if (loadfile ("ovrldemo.1", &_OVERLAY1_LOAD__, &_OVERLAY1_SIZE__)) {
+ ** linker. They contain the overlay area address and size specific to a
+ ** certain program.
+ */
+ if (loadfile ("ovrldemo.1", _OVERLAY1_LOAD__, _OVERLAY1_SIZE__)) {
/* The linker makes sure that the call to foo() ends up at the right mem
- * addr. However it's up to user to make sure that the - right - overlay
- * is actually loaded before making the the call.
- */
+ ** addr. However it's up to user to make sure that the - right - overlay
+ ** is actually loaded before making the the call.
+ */
foo ();
}
log ("Calling overlay 2 from main");
/* Replacing one overlay with another one can only happen from the main
- * program. This implies that an overlay can never load another overlay.
- */
- if (loadfile ("ovrldemo.2", &_OVERLAY2_LOAD__, &_OVERLAY2_SIZE__)) {
+ ** program. This implies that an overlay can never load another overlay.
+ */
+ if (loadfile ("ovrldemo.2", _OVERLAY2_LOAD__, _OVERLAY2_SIZE__)) {
bar ();
}
log ("Calling overlay 3 from main");
- if (loadfile ("ovrldemo.3", &_OVERLAY3_LOAD__, &_OVERLAY3_SIZE__)) {
+ if (loadfile ("ovrldemo.3", _OVERLAY3_LOAD__, _OVERLAY3_SIZE__)) {
foobar ();
}
- cgetc ();
+ if (doesclrscrafterexit ()) {
+ getchar ();
+ }
}