Add APU-related debugger commands

This change includes making one of the APU functions public

Core/apu.c

@@ -21,7 +21,7 @@ static void refresh_channel(GB_gameboy_t *gb, unsigned index, unsigned cycles_of
     gb->apu_output.last_update[index] = gb->apu_output.cycles_since_render + cycles_offset;
 }
 
-static bool is_DAC_enabled(GB_gameboy_t *gb, unsigned index)
+bool GB_apu_is_DAC_enabled(GB_gameboy_t *gb, unsigned index)
 {
     switch (index) {
         case GB_SQUARE_1:
@@ -42,7 +42,7 @@ static bool is_DAC_enabled(GB_gameboy_t *gb, unsigned index)
 
 static void update_sample(GB_gameboy_t *gb, unsigned index, int8_t value, unsigned cycles_offset)
 {
-    if (!is_DAC_enabled(gb, index)) {
+    if (!GB_apu_is_DAC_enabled(gb, index)) {
         value = gb->apu.samples[index];
     }
     else {
@@ -73,7 +73,7 @@ static void render(GB_gameboy_t *gb, bool no_downsampling, GB_sample_t *dest)
     UNROLL
     for (unsigned i = 0; i < GB_N_CHANNELS; i++) {
         double multiplier = CH_STEP;
-        if (!is_DAC_enabled(gb, i)) {
+        if (!GB_apu_is_DAC_enabled(gb, i)) {
             gb->apu_output.dac_discharge[i] -= ((double) DAC_DECAY_SPEED) / gb->apu_output.sample_rate;
             if (gb->apu_output.dac_discharge[i] < 0) {
                 multiplier = 0;

Core/apu.h

@@ -160,6 +160,7 @@ size_t GB_apu_get_current_buffer_length(GB_gameboy_t *gb);
 void GB_set_highpass_filter_mode(GB_gameboy_t *gb, GB_highpass_mode_t mode);
 
 #ifdef GB_INTERNAL
+bool GB_apu_is_DAC_enabled(GB_gameboy_t *gb, unsigned index);
 void GB_apu_write(GB_gameboy_t *gb, uint8_t reg, uint8_t value);
 uint8_t GB_apu_read(GB_gameboy_t *gb, uint8_t reg);
 void GB_apu_div_event(GB_gameboy_t *gb);

Core/debugger.c

@@ -1570,6 +1570,172 @@ static bool lcd(GB_gameboy_t *gb, char *arguments, char *modifiers, const debugg
     return true;
 }
 
+static bool apu(GB_gameboy_t *gb, char *arguments, char *modifiers, const debugger_command_t *command)
+{
+    NO_MODIFIERS
+    if (strlen(lstrip(arguments))) {
+        print_usage(gb, command);
+        return true;
+    }
+
+
+    GB_log(gb, "Current state: ");
+    if(!gb->apu.global_enable) {
+        GB_log(gb, "Disabled\n");
+    }
+    else {
+        GB_log(gb, "Enabled\n");
+        for(uint8_t channel = 0; channel < GB_N_CHANNELS; channel++) {
+            GB_log(gb, "CH%u is %s, DAC %s; current sample = 0x%x\n", channel + 1,
+                gb->apu.is_active[channel] ? "active  " : "inactive",
+                GB_apu_is_DAC_enabled(gb, channel) ? "active  " : "inactive",
+                gb->apu.samples[channel]);
+        }
+    }
+
+    GB_log(gb, "SO1 (left output):  volume %u,", gb->io_registers[GB_IO_NR50] & 0x07);
+    if(gb->io_registers[GB_IO_NR51] & 0x0f) {
+        for(uint8_t channel = 0, mask = 0x01; channel < GB_N_CHANNELS; channel++, mask <<= 1) {
+            if(gb->io_registers[GB_IO_NR51] & mask) {
+                GB_log(gb, " CH%u", channel + 1);
+            }
+        }
+    } else {
+        GB_log(gb, " no channels");
+    }
+    GB_log(gb, "%s\n", gb->io_registers[GB_IO_NR50] & 0x80 ? " VIN": "");
+
+    GB_log(gb, "SO2 (right output): volume %u,", gb->io_registers[GB_IO_NR50] & 0x70 >> 4);
+    if(gb->io_registers[GB_IO_NR51] & 0xf0) {
+        for(uint8_t channel = 0, mask = 0x10; channel < GB_N_CHANNELS; channel++, mask <<= 1) {
+            if(gb->io_registers[GB_IO_NR51] & mask) {
+                GB_log(gb, " CH%u", channel + 1);
+            }
+        }
+    } else {
+        GB_log(gb, " no channels");
+    }
+    GB_log(gb, "%s\n", gb->io_registers[GB_IO_NR50] & 0x80 ? " VIN": "");
+
+
+    for(uint8_t channel = GB_SQUARE_1; channel <= GB_SQUARE_2; channel++) {
+        GB_log(gb, "\nCH%u:\n", channel + 1);
+        GB_log(gb, "    Current volume: %u, current sample length: %u APU ticks (next in %u ticks)\n",
+            gb->apu.square_channels[channel].current_volume,
+            gb->apu.square_channels[channel].sample_length,
+            gb->apu.square_channels[channel].sample_countdown);
+
+        uint8_t nrx2 = gb->io_registers[channel == GB_SQUARE_1? GB_IO_NR12 : GB_IO_NR22];
+        GB_log(gb, "    %u 256 Hz ticks till next volume %screase (out of %u)\n",
+            gb->apu.square_channels[channel].volume_countdown,
+            nrx2 & 8 ? "in" : "de",
+            nrx2 & 7);
+
+        uint8_t duty = gb->io_registers[channel == GB_SQUARE_1? GB_IO_NR11 :GB_IO_NR21] >> 6;
+        GB_log(gb, "    Duty cycle %s%% (%s), current index %u/8%s\n",
+            (char*[]){"12.5", "  25", "  50", "  75"}[duty],
+            (char*[]){"_______-", "-______-", "-____---", "_------_"}[duty],
+            gb->apu.square_channels[channel].current_sample_index & 0x7f,
+            gb->apu.square_channels[channel].current_sample_index >> 7 ? " (suppressed)" : "");
+
+        if(channel == GB_SQUARE_1) {
+            GB_log(gb, "    Frequency sweep %s and %s (next in %u APU ticks)\n",
+                gb->apu.sweep_enabled? "active" : "inactive",
+                gb->apu.sweep_decreasing? "decreasing" : "increasing",
+                gb->apu.square_sweep_calculate_countdown);
+        }
+
+        if(gb->apu.square_channels[channel].length_enabled) {
+            GB_log(gb, "    Channel will end in %u 256 Hz ticks\n",
+                gb->apu.square_channels[channel].pulse_length);
+        }
+    }
+
+
+    GB_log(gb, "\nCH3:\n");
+    GB_log(gb, "    Wave:");
+    for(uint8_t i = 0; i < 32; i++) {
+        GB_log(gb, "%s%X", i%4?"":" ", gb->apu.wave_channel.wave_form[i]);
+    }
+    GB_log(gb, ", has %sjust been read\n", gb->apu.wave_channel.wave_form_just_read? "": "not ");
+    GB_log(gb, "    Current position: %u\n", gb->apu.wave_channel.current_sample_index);
+
+    GB_log(gb, "    Volume %s (right-shifted %ux)\n",
+        (char*[]){"100%", "50%", "25%", NULL, "muted"}[gb->apu.wave_channel.shift],
+        gb->apu.wave_channel.shift);
+
+    GB_log(gb, "    Current sample length: %u APU ticks (next in %u ticks)\n",
+        gb->apu.wave_channel.sample_length,
+        gb->apu.wave_channel.sample_countdown);
+
+    if(gb->apu.wave_channel.length_enabled) {
+        GB_log(gb, "    Channel will end in %u 256 Hz ticks\n",
+            gb->apu.wave_channel.pulse_length);
+    }
+
+
+    GB_log(gb, "\nCH4:\n");
+    GB_log(gb, "    Current volume: %u, current sample length: %u APU ticks (next in %u ticks)\n",
+        gb->apu.noise_channel.current_volume,
+        gb->apu.noise_channel.sample_length,
+        gb->apu.noise_channel.sample_countdown);
+
+    GB_log(gb, "    %u 256 Hz ticks till next volume %screase (out of %u)\n",
+        gb->apu.noise_channel.volume_countdown,
+        gb->io_registers[GB_IO_NR42] & 8 ? "in" : "de",
+        gb->io_registers[GB_IO_NR42] & 7);
+
+    GB_log(gb, "    LFSR in %u-step mode, current value %%",
+        gb->apu.noise_channel.narrow? 7 : 15);
+    for(uint16_t lfsr = gb->apu.noise_channel.lfsr, i = 15; i--; lfsr <<= 1) {
+        GB_log(gb, "%u%s", (lfsr >> 14) & 1, i%4 ? "" : " ");
+    }
+
+    if(gb->apu.noise_channel.length_enabled) {
+        GB_log(gb, "    Channel will end in %u 256 Hz ticks\n",
+            gb->apu.noise_channel.pulse_length);
+    }
+
+
+    GB_log(gb, "\n\nReminder: APU ticks are @ 2 MiHz\n");
+
+    return true;
+}
+
+static bool wave(GB_gameboy_t *gb, char *arguments, char *modifiers, const debugger_command_t *command)
+{
+    if (strlen(lstrip(arguments)) || (modifiers && !strchr("fcl", modifiers[0]))) {
+        print_usage(gb, command);
+        return true;
+    }
+
+    uint8_t shift_amount = 1, mask;
+    if(modifiers) {
+        switch(modifiers[0]) {
+            case 'c':
+                shift_amount = 2;
+                break;
+            case 'l':
+                shift_amount = 8;
+                break;
+        }
+    }
+    mask = (0xf << (shift_amount - 1)) & 0xf;
+
+    for(int8_t cur_val = 0xf & mask; cur_val >= 0; cur_val -= shift_amount) {
+        for(uint8_t i = 0; i < 32; i++) {
+            if((gb->apu.wave_channel.wave_form[i] & mask) == cur_val) {
+                GB_log(gb, "%X", gb->apu.wave_channel.wave_form[i]);
+            } else {
+                GB_log(gb, "%c", i%4 == 2 ? '-' : ' ');
+            }
+        }
+        GB_log(gb, "\n");
+    }
+
+    return true;
+}
+
 static bool help(GB_gameboy_t *gb, char *arguments, char *modifiers, const debugger_command_t *command);
 
 #define HELP_NEWLINE "\n             "
@@ -1587,6 +1753,10 @@ static const debugger_command_t commands[] = {
     {"registers", 1, registers, "Print values of processor registers and other important registers"},
     {"cartridge", 2, mbc, "Displays information about the MBC and cartridge"},
     {"mbc", 3, }, /* Alias */
+    {"apu", 3, apu, "Displays information about the current state of the audio chip"},
+    {"wave", 3, wave, "Prints a visual representation of the wave RAM" HELP_NEWLINE
+                      "Modifiers can be used for a (f)ull print (the default)," HELP_NEWLINE
+                      "a more (c)ompact one, or a one-(l)iner"},
     {"lcd", 3, lcd, "Displays information about the current state of the LCD controller"},
     {"palettes", 3, palettes, "Displays the current CGB palettes"},
     {"breakpoint", 1, breakpoint, "Add a new breakpoint at the specified address/expression" HELP_NEWLINE