Rename video_mode -> display_mode

This also changes the _kind_ of field from an incrementally enumerated
one to a collection of bit flags.

include/apple2.h

@@ -35,15 +35,6 @@
  */
 #define APPLE2_APPLESOFT_MAIN 0xE000
 
-enum video_modes {
-    VIDEO_40COL_TEXT,
-    VIDEO_LORES,
-    VIDEO_HIRES,
-    VIDEO_80COL_TEXT,
-    VIDEO_DOUBLE_LORES,
-    VIDEO_DOUBLE_HIRES,
-};
-
 enum color_modes {
     COLOR_GREEN,
     COLOR_AMBER,
@@ -154,6 +145,50 @@ enum memory_mode {
     MEMORY_SLOTC3ROM = 0x80,
 };
 
+enum display_mode {
+    DISPLAY_DEFAULT = 0x0,
+
+    /*
+     * Display text in the "alternate" character set
+     */
+    DISPLAY_ALTCHAR = 0x1,
+
+    /*
+     * Show text in 80 columns, rather than the default 40 columns
+     */
+    DISPLAY_80COL = 0x2,
+
+    /*
+     * Display only text. By default, we display lo-res graphics and
+     * perhaps mixed graphics and text if the MIXED bit is high.
+     */
+    DISPLAY_TEXT = 0x4,
+
+    /*
+     * If TEXT is not high, then we are directed to display both text
+     * and graphics.
+     */
+    DISPLAY_MIXED = 0x8,
+
+    /*
+     * If this is high, we will show high-resolution graphics; if not,
+     * low-resolution. This bit is overridden by TEXT; if TEXT is high,
+     * we will only show text.
+     */
+    DISPLAY_HIRES = 0x10,
+
+    /*
+     * Enable IOU access for $C058..$C05F when this bit is on; NOTE: the
+     * tech ref says that this is left on by the firmware
+     */
+    DISPLAY_IOUDIS = 0x20,
+
+    /*
+     * Display double-high-resolution graphics
+     */
+    DISPLAY_DHIRES = 0x40,
+};
+
 enum bank_switch {
     /*
      * In nominal bank-switch mode, reads in the bank-switchable address
@@ -243,9 +278,9 @@ typedef struct {
     /*
      * This is the mode in which we must interpret graphics. This will
      * tell us not only if we're in lo- or hi-res, but also if we are in
-     * single or double view mode.
+     * single or double view mode. Among other things!
      */
-    int video_mode;
+    vm_8bit display_mode;
 
     /*
      * This is the color mode we want to emulate. You can have a few
@@ -288,6 +323,6 @@ extern void apple2_run_loop(apple2 *);
 extern void apple2_set_bank_switch(apple2 *, vm_8bit);
 extern void apple2_set_color(apple2 *, int);
 extern void apple2_set_memory_mode(apple2 *, vm_8bit);
-extern void apple2_set_video(apple2 *, int);
+extern void apple2_set_display(apple2 *, vm_8bit);
 
 #endif

src/apple2.c

@@ -125,7 +125,7 @@ apple2_create(int width, int height)
     apple2_set_color(mach, COLOR_FULL);
 
     // We default to lo-res mode.
-    apple2_set_video(mach, VIDEO_LORES);
+    apple2_set_display(mach, DISPLAY_DEFAULT);
 
     // Let's install our bitmap font.
     mach->sysfont = vm_bitfont_create(mach->screen,
@@ -193,9 +193,7 @@ bool
 apple2_is_double_video(apple2 *mach)
 {
     return 
-        mach->video_mode == VIDEO_DOUBLE_HIRES ||
-        mach->video_mode == VIDEO_DOUBLE_LORES ||
-        mach->video_mode == VIDEO_80COL_TEXT;
+        mach->display_mode & DISPLAY_DHIRES;
 }
 
 /*
@@ -255,7 +253,7 @@ apple2_reset(apple2 *mach)
     mach->cpu->S = 0;
 
     // Switch video mode back to 40 column text
-    apple2_set_video(mach, VIDEO_40COL_TEXT);
+    apple2_set_display(mach, DISPLAY_DEFAULT);
 
     // Switch us back to defaults
     apple2_set_bank_switch(mach, BANK_DEFAULT);
@@ -388,15 +386,15 @@ apple2_set_color(apple2 *mach, int mode)
 }
 
 /*
- * Set the video mode of the display. This would be the type of
+ * Set the display mode of the display. This would be the type of
  * resolution (text by which number of columns, lo-res, hi-res, etc.)
  */
 void
-apple2_set_video(apple2 *mach, int mode)
+apple2_set_display(apple2 *mach, vm_8bit mode)
 {
     int width, height;
 
-    mach->video_mode = mode;
+    mach->display_mode = mode;
 
     // In the traditional video modes that Apple II first came in, you
     // would have a maximum width of 280 pixels. (In lo-res, you have
@@ -407,9 +405,7 @@ apple2_set_video(apple2 *mach, int mode)
 
     // In double video modes, the width is effectively doubled, but the
     // height is untouched.
-    if (mach->video_mode == VIDEO_DOUBLE_LORES ||
-        mach->video_mode == VIDEO_DOUBLE_HIRES
-       ) {
+    if (apple2_is_double_video(mach)) {
         width = 560;
     }
 

tests/apple2.c

@@ -34,29 +34,10 @@ Test(apple2, create)
 
 Test(apple2, is_double_video)
 {
-    for (int i = 0; i <= VIDEO_DOUBLE_HIRES; i++) {
-        mach->video_mode = i;
-        switch (i) {
-            case VIDEO_40COL_TEXT:
+    mach->display_mode = DISPLAY_DEFAULT;
     cr_assert_eq(apple2_is_double_video(mach), false);
-                break;
-            case VIDEO_LORES:
-                cr_assert_eq(apple2_is_double_video(mach), false);
-                break;
-            case VIDEO_HIRES:
-                cr_assert_eq(apple2_is_double_video(mach), false);
-                break;
-            case VIDEO_80COL_TEXT:
+    mach->display_mode = DISPLAY_DHIRES;
     cr_assert_eq(apple2_is_double_video(mach), true);
-                break;
-            case VIDEO_DOUBLE_LORES:
-                cr_assert_eq(apple2_is_double_video(mach), true);
-                break;
-            case VIDEO_DOUBLE_HIRES:
-                cr_assert_eq(apple2_is_double_video(mach), true);
-                break;
-        }
-    }
 }
 
 Test(apple2, boot)
@@ -109,12 +90,12 @@ Test(apple2, set_color)
     cr_assert_eq(mach->color_mode, COLOR_FULL);
 }
 
-Test(apple2, set_video)
+Test(apple2, set_display)
 {
-    apple2_set_video(mach, VIDEO_DOUBLE_HIRES);
-    cr_assert_eq(mach->video_mode, VIDEO_DOUBLE_HIRES);
-    apple2_set_video(mach, VIDEO_LORES);
-    cr_assert_eq(mach->video_mode, VIDEO_LORES);
+    apple2_set_display(mach, DISPLAY_DHIRES);
+    cr_assert_eq(mach->display_mode, DISPLAY_DHIRES);
+    apple2_set_display(mach, DISPLAY_TEXT);
+    cr_assert_eq(mach->display_mode, DISPLAY_TEXT);
 }
 
 Test(apple2, set_bank_switch)