Add switch read/write for display buffer switches

include/apple2.dbuf.h

@@ -7,5 +7,7 @@
 extern SEGMENT_READER(apple2_dbuf_read);
 extern SEGMENT_WRITER(apple2_dbuf_write);
 extern void apple2_dbuf_map(vm_segment *);
+extern SEGMENT_READER(apple2_dbuf_switch_read);
+extern SEGMENT_WRITER(apple2_dbuf_switch_write);
 
 #endif

src/apple2.dbuf.c

@@ -4,6 +4,33 @@
 
 #include "apple2.dbuf.h"
 
+static size_t switch_reads[] = {
+    0xC01A,
+    0xC01B,
+    0xC01E,
+    0xC01F,
+    0xC07E,
+    0xC07F,
+};
+
+static size_t switch_writes[] = {
+    0xC00C,
+    0xC00D,
+    0xC00E,
+    0xC00F,
+    0xC050,
+    0xC051,
+    0xC052,
+    0xC053,
+    0xC056,
+    0xC057,
+    0xC059,
+    0xC05E,
+    0xC05F,
+    0xC07E,
+    0xC07F,
+};
+
 /*
  * Handle reads from text page 1 and hires graphics page 1 (the display
  * buffers).
@@ -71,6 +98,7 @@ void
 apple2_dbuf_map(vm_segment *segment)
 {
     size_t addr;
+    int i, rlen, wlen;
 
     for (addr = 0x400; addr < 0x800; addr++) {
         vm_segment_read_map(segment, addr, apple2_dbuf_read);
@@ -81,13 +109,140 @@ apple2_dbuf_map(vm_segment *segment)
         vm_segment_read_map(segment, addr, apple2_dbuf_read);
         vm_segment_write_map(segment, addr, apple2_dbuf_write);
     }
+
+    rlen = sizeof(switch_reads) / sizeof(size_t);
+    wlen = sizeof(switch_writes) / sizeof(size_t);
+
+    for (i = 0; i < rlen; i++) {
+        vm_segment_read_map(segment, switch_reads[i], apple2_dbuf_switch_read);
+    }
+
+    for (i = 0; i < wlen; i++) {
+        vm_segment_write_map(segment, switch_writes[i], apple2_dbuf_switch_write);
+    }
 }
 
 /*
  * Handle all read switches for display buffer code. Some switches
  * respond to either reads _or_ writes, so you may see some cases
  * duplicated in the write map.
+ *
+ * Additionally, a number of the display modes also count as memory
+ * modes, and are handled in apple2.mem.c. Notably, some are HIRES,
+ * PAGE2, and 80STORE.
  */
 SEGMENT_READER(apple2_dbuf_switch_read)
 {
+    apple2 *mach = (apple2 *)_mach;
+
+    switch (addr) {
+        case 0xC01E:
+            return mach->display_mode & DISPLAY_ALTCHAR
+                ? 0x80
+                : 0x00;
+
+        case 0xC01F:
+            return mach->display_mode & DISPLAY_80COL
+                ? 0x80
+                : 0x00;
+
+        case 0xC01A:
+            return mach->display_mode & DISPLAY_TEXT
+                ? 0x80
+                : 0x00;
+
+        case 0xC01B:
+            return mach->display_mode & DISPLAY_MIXED
+                ? 0x80
+                : 0x00;
+
+        // NOTE: IOUDIS is the only bit that seems to share a write
+        // address with a read address. We can certainly handle that,
+        // since we support separate read and write tables! But it's
+        // interesting that they chose to do that, where they mostly
+        // stick with separate addresses for separate functions.
+        case 0xC07E:
+            return mach->display_mode & DISPLAY_IOUDIS
+                ? 0x80
+                : 0x00;
+
+        case 0xC07F:
+            return mach->display_mode & DISPLAY_DHIRES
+                ? 0x80
+                : 0x00;
+    }
+
+    // ???
+    return 0;
+}
+
+/*
+ * Here we update the statuses of the various display soft switches,
+ * and--there's a bunch of them!
+ */
+SEGMENT_WRITER(apple2_dbuf_switch_write)
+{
+    apple2 *mach = (apple2 *)_mach;
+
+    switch (addr) {
+        case 0xC00E:
+            apple2_set_display(mach,
+                               mach->display_mode | DISPLAY_ALTCHAR);
+            break;
+
+        case 0xC00F:
+            apple2_set_display(mach,
+                               mach->display_mode & ~DISPLAY_ALTCHAR);
+            break;
+
+        case 0xC00C:
+            apple2_set_display(mach,
+                               mach->display_mode | DISPLAY_80COL);
+            break;
+
+        case 0xC00D:
+            apple2_set_display(mach,
+                               mach->display_mode & ~DISPLAY_80COL);
+            break;
+
+        case 0xC050:
+            apple2_set_display(mach,
+                               mach->display_mode | DISPLAY_TEXT);
+            break;
+
+        case 0xC051:
+            apple2_set_display(mach,
+                               mach->display_mode & ~DISPLAY_TEXT);
+            break;
+
+        case 0xC052:
+            apple2_set_display(mach,
+                               mach->display_mode | DISPLAY_MIXED);
+            break;
+
+        case 0xC053:
+            apple2_set_display(mach,
+                               mach->display_mode & ~DISPLAY_MIXED);
+            break;
+
+        case 0xC07E:
+            apple2_set_display(mach,
+                               mach->display_mode | DISPLAY_IOUDIS);
+            break;
+
+        case 0xC07F:
+            apple2_set_display(mach,
+                               mach->display_mode & ~DISPLAY_IOUDIS);
+            break;
+
+        case 0xC05E:
+            apple2_set_display(mach,
+                               mach->display_mode | DISPLAY_DHIRES);
+            break;
+
+        case 0xC05F:
+            apple2_set_display(mach,
+                               mach->display_mode & ~DISPLAY_DHIRES);
+            break;
+    }
 }