Fix dynamic sound disabling, add notification system

Makefile

@@ -54,7 +54,6 @@ bootsect: $(BOOTSECT_OBJS)
 kernel: $(KERNEL_OBJS)
 	$(LD) -o ./bin/$(KERNEL) $^ $(LDFLAGS) -Tsrc/link.ld
 
-<<<<<<< HEAD
 img: dirs bootsect kernel
 	dd if=/dev/zero of=$(IMG) bs=512 count=2880
 	dd if=./bin/$(BOOTSECT) of=boot.img conv=notrunc bs=512 seek=0 count=1

src/main.c

@@ -1,6 +1,3 @@
-// remove to disable music, useful when building for hardware without an SB16
-#define ENABLE_MUSIC
-
 #include "util.h"
 #include "screen.h"
 #include "idt.h"
@@ -12,11 +9,8 @@
 #include "keyboard.h"
 #include "speaker.h"
 #include "fpu.h"
-
-#ifdef ENABLE_MUSIC
 #include "sound.h"
 #include "music.h"
-#endif
 
 #define FPS 30
 #define LEVELS 30
@@ -702,12 +696,13 @@ void _main(u32 magic) {
     keyboard_init();
     generate_sprites();
 
-#ifdef ENABLE_MUSIC
     sound_init();
-    music_init();
-    state.music = true;
-    sound_master(255);
-#endif
+
+    if (sound_enabled()) {
+        music_init();
+        state.music = true;
+        sound_master(255);
+    }
 
     state.menu = true;
 
@@ -718,12 +713,10 @@ void _main(u32 magic) {
     while (true) {
         const u32 now = (u32) timer_get();
 
-#ifdef ENABLE_MUSIC
-        if (now != last) {
+        if (sound_enabled() && now != last) {
             music_tick();
             last = now;
         }
-#endif
 
         if ((now - last_frame) > (TIMER_TPS / FPS)) {
             last_frame = now;
@@ -736,8 +729,7 @@ void _main(u32 magic) {
                 render();
             }
 
-#ifdef ENABLE_MUSIC
-            if (keyboard_char('m')) {
+            if (sound_enabled() && keyboard_char('m')) {
                 if (!last_music_toggle) {
                     state.music = !state.music;
                     sound_master(state.music ? 255 : 0);
@@ -747,7 +739,12 @@ void _main(u32 magic) {
             } else {
                 last_music_toggle = false;
             }
-#endif
+
+            // controlled in system.c
+            const char *notification = get_notification();
+            if (notification != NULL) {
+                font_str_doubled(notification, 0, 0, COLOR(6, 1, 1));
+            }
 
             screen_swap();
             state.frames++;

src/music.c

@@ -303,11 +303,7 @@ static size_t PART_LENGTHS[TRACK_PARTS];
 static i32 indices[TRACK_PARTS];
 static struct NoteActive current[NUM_NOTES];
 
-extern bool sound_enabled;
-
 void music_tick() {
-    if (!sound_enabled) return;
-
     for (size_t i = 0; i < TRACK_PARTS; i++) {
         if (indices[i] == -1 || (current[i].ticks -= 1) <= 0) {
             indices[i] = (indices[i] + 1) % PART_LENGTHS[i];
@@ -329,8 +325,6 @@ void music_tick() {
 }
 
 void music_init() {
-    if (!sound_enabled) return;
-
     sound_wave(0, WAVE_TRIANGLE);
     sound_volume(0, 255);
 

src/sound.c

@@ -147,12 +147,12 @@ static const f64 NOTES[NUM_OCTAVES * OCTAVE_SIZE] = {
 #define DSP_VOLUME  0x22
 #define DSP_IRQ     0x80
 
-#define SAMPLE_RATE     48000
+#define SAMPLE_RATE     21500
 #define BUFFER_MS       40
 
 #define BUFFER_SIZE ((size_t) (SAMPLE_RATE * (BUFFER_MS / 1000.0)))
 
-bool sound_enabled = false;
+static bool is_enabled = false;
 
 static i16 buffer[BUFFER_SIZE];
 static bool buffer_flip = false;
@@ -164,6 +164,14 @@ static u8 volumes[NUM_NOTES];
 static u8 notes[NUM_NOTES];
 static u8 waves[NUM_NOTES];
 
+bool sound_enabled() {
+    return is_enabled;
+}
+
+void sound_set_enabled(bool enabled) {
+    is_enabled = enabled;
+}
+
 void sound_note(u8 index, u8 octave, u8 note) {
     notes[index] = (octave << 4) | note;
 }
@@ -181,8 +189,6 @@ void sound_wave(u8 index, u8 wave) {
 }
 
 static void fill(i16 *buf, size_t len) {
-    if (!sound_enabled) return;
-
     for (size_t i = 0; i < len; i++) {
         double f = 0.0;
 
@@ -230,15 +236,11 @@ static void fill(i16 *buf, size_t len) {
 }
 
 static void dsp_write(u8 b) {
-    if (!sound_enabled) return;
-
     while (inportb(DSP_WRITE) & 0x80);
     outportb(DSP_WRITE, b);
 }
 
 static void dsp_read(u8 b) {
-    if (!sound_enabled) return;
-
     while (inportb(DSP_READ_STATUS) & 0x80);
     outportb(DSP_READ, b);
 }
@@ -247,11 +249,6 @@ static void reset() {
     char buf0[128], buf1[128];
 
     outportb(DSP_RESET, 1);
-
-    // TODO: maybe not necessary
-    // ~3 microseconds?
-    for (size_t i = 0; i < 1000000; i++);
-
     outportb(DSP_RESET, 0);
 
     u8 status = inportb(DSP_READ_STATUS);
@@ -273,22 +270,23 @@ static void reset() {
         goto fail;
     }
 
-    sound_enabled = true;
+    sound_set_enabled(true);
+    return;
 fail:
+    strlcpy(buf0, "FAILED TO RESET SB16: ", 128);
+    itoa(status, buf1, 128);
+    strlcat(buf0, buf1, 128);
+    notify(buf0);
     return;
 }
 
 static void set_sample_rate(u16 hz) {
-    if (!sound_enabled) return;
-
     dsp_write(DSP_SET_RATE);
     dsp_write((u8) ((hz >> 8) & 0xFF));
     dsp_write((u8) (hz & 0xFF));
 }
 
 static void transfer(void *buf, u32 len) {
-    if (!sound_enabled) return;
-
     u8 mode = 0x48;
 
     // disable DMA channel
@@ -317,8 +315,6 @@ static void transfer(void *buf, u32 len) {
 }
 
 static void sb16_irq_handler(struct Registers *regs) {
-    if (!sound_enabled) return;
-
     buffer_flip = !buffer_flip;
 
     fill(
@@ -348,7 +344,10 @@ static void configure() {
 void sound_init() {
     irq_install(MIXER_IRQ, sb16_irq_handler);
     reset();
-    if (!sound_enabled) return;
+
+    if (!sound_enabled()) {
+        return;
+    }
 
     configure();
 

src/sound.h

@@ -41,6 +41,8 @@
 #define WAVE_NOISE      2
 #define WAVE_TRIANGLE   3
 
+bool sound_enabled();
+void sound_set_enabled(bool enabled);
 void sound_init();
 void sound_note(u8 index, u8 octave, u8 note);
 void sound_master(u8 v);

src/system.c

@@ -1,6 +1,16 @@
 #include "system.h"
 #include "screen.h"
 #include "font.h"
+#include "timer.h"
+
+#define NOTIFICATION_DURATION_TICKS (TIMER_TPS * 2)
+
+static struct {
+    char content[512];
+    u64 ticks;
+} notification = {
+    "", -1
+};
 
 static u32 rseed = 1;
 
@@ -33,3 +43,19 @@ void panic(const char *err) {
     screen_swap();
     for (;;) {}
 }
+
+const char *get_notification() {
+    return timer_get() - notification.ticks <= NOTIFICATION_DURATION_TICKS ?
+        ((const char *) &notification.content) : NULL;
+}
+
+void notify(const char *message) {
+    memcpy(
+        &notification.content,
+        message,
+        MIN(strlen(message) + 1, sizeof(notification.content))
+    );
+
+    notification.content[sizeof(notification.content) - 1] = 0;
+    notification.ticks = timer_get();
+}

src/system.h

@@ -14,6 +14,8 @@
         _assert_1(__VA_ARGS__),\
         _assert_0(__VA_ARGS__))
 
+const char *get_notification();
+void notify(const char *err);
 void panic(const char *err);
 u32 rand();
 void seed(u32 s);