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ds: Replace magic numbers in mixer by definitions #17

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52 changes: 37 additions & 15 deletions source/ds/arm7/mixer.c
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Original file line number Diff line number Diff line change
Expand Up @@ -23,10 +23,33 @@
#define SWM_CHANNEL_1 6
#define SWM_CHANNEL_2 7

#define ROUND_CLOSEST(dividend, divisor) (((dividend) + (((divisor) + 1) >> 1)) / (divisor))

#define MIX_TIMER_NUMBER 0

#define SFRAC 10

#define MIX_TIMER_256_HZ_FREQ 1024
#define MIX_TIMER_256_HZ_DIV TIMER_DIV_1024
#define MIX_TIMER_194_8125_HZ_FREQ 256
#define MIX_TIMER_194_8125_HZ_DIV TIMER_DIV_256

// Get the value closest to -((BUS_CLOCK / frequency) / hz), where hz can be a non-integer value
#define MIX_TIMER_SET_VALUE(x, divisor, frequency) (-ROUND_CLOSEST(BUS_CLOCK, ROUND_CLOSEST((x) * (frequency), divisor)))
#define MIX_TIMER_SET_256_HZ_VALUE(x, divisor) MIX_TIMER_SET_VALUE(x, divisor, MIX_TIMER_256_HZ_FREQ)
#define MIX_TIMER_SET_194_8125_HZ_VALUE(x, divisor) MIX_TIMER_SET_VALUE(x, divisor, MIX_TIMER_194_8125_HZ_FREQ)

// Get the sound timer value closest to the effective frequency of the previously calculated timer -((BUS_CLOCK / 2) / (real_freq * num_samples))
// num_samples is the amount of samples per "regular timer" call.
#define MIX_SOUND_TIMER_SET_VALUE(timer_value, frequency, num_samples) (-ROUND_CLOSEST(BUS_CLOCK, ROUND_CLOSEST(((int64_t)BUS_CLOCK) * 2 * (num_samples), (timer_value) * (frequency))))
#define MIX_SOUND_TIMER_SET_256_HZ_VALUE(x, divisor, num_samples) MIX_SOUND_TIMER_SET_VALUE(-MIX_TIMER_SET_256_HZ_VALUE(x, divisor), MIX_TIMER_256_HZ_FREQ, num_samples)
#define MIX_SOUND_TIMER_SET_194_8125_HZ_VALUE(x, divisor, num_samples) MIX_SOUND_TIMER_SET_VALUE(-MIX_TIMER_SET_194_8125_HZ_VALUE(x, divisor), MIX_TIMER_194_8125_HZ_FREQ, num_samples)

// Get the resolution closest to the effective frequency of the previously calculated timer (BUS_CLOCK * 2.5 * 64) / real_freq
#define RESOLUTION_VALUE(timer_value, frequency) (ROUND_CLOSEST(((int64_t)BUS_CLOCK) * 5 * (64 / 2), (timer_value) * (frequency)))
#define RESOLUTION_256_HZ_VALUE(x, divisor) RESOLUTION_VALUE(-MIX_TIMER_SET_256_HZ_VALUE(x, divisor), MIX_TIMER_256_HZ_FREQ)
#define RESOLUTION_194_8125_HZ_VALUE(x, divisor) RESOLUTION_VALUE(-MIX_TIMER_SET_194_8125_HZ_VALUE(x, divisor), MIX_TIMER_194_8125_HZ_FREQ)

mm_mixer_channel mm_mix_channels[MM_nDSCHANNELS];

mm_mode_enum mm_mixing_mode; // [0/1/2 = a/b/c] (MM_MODE_A/B/C)
Expand Down Expand Up @@ -96,8 +119,7 @@ static void mmSetupModeB(void)
{
// Disable timer
TIMER_CR(MIX_TIMER_NUMBER) = 0;

mmSetResolution(40960);
mmSetResolution(RESOLUTION_256_HZ_VALUE(256, 1));

mm_word bitmask = mm_ch_mask;
for (int i = 0; i < NUM_PHYS_CHANNELS; i++)
Expand All @@ -106,7 +128,7 @@ static void mmSetupModeB(void)
{
SCHANNEL_CR(i) = 0xA8000000;
SCHANNEL_SOURCE(i) = (uintptr_t)mm_mix_data.mix_data_b.output[i];
SCHANNEL_TIMER(i) = 0xFE00;
SCHANNEL_TIMER(i) = MIX_SOUND_TIMER_SET_256_HZ_VALUE(256, 1, MM_MIX_B_NUM_SAMPLES);
SCHANNEL_REPEAT_POINT(i) = 0;
SCHANNEL_LENGTH(i) = MM_MIX_B_NUM_SAMPLES;
}
Expand All @@ -119,8 +141,8 @@ static void mmSetupModeB(void)

mm_startup_wait();

TIMER_DATA(MIX_TIMER_NUMBER) = 0xFF80;
TIMER_CR(MIX_TIMER_NUMBER) = 0x00C3;
timerStart(MIX_TIMER_NUMBER, MIX_TIMER_256_HZ_DIV, MIX_TIMER_SET_256_HZ_VALUE(256, 1), NULL);
TIMER_CR(MIX_TIMER_NUMBER) |= TIMER_IRQ_REQ;
}

static void SetupSWM(void)
Expand All @@ -141,8 +163,8 @@ static void SetupSWM(void)
SCHANNEL_SOURCE(SWM_CHANNEL_2) = (uintptr_t)mm_mix_data.mix_data_c.mix_output[1];

// Set sampling frequency
SCHANNEL_TIMER(SWM_CHANNEL_1) = -768;
SCHANNEL_TIMER(SWM_CHANNEL_2) = -768;
SCHANNEL_TIMER(SWM_CHANNEL_1) = MIX_SOUND_TIMER_SET_194_8125_HZ_VALUE(3117, 16, MM_SW_BUFFERLEN/2);
SCHANNEL_TIMER(SWM_CHANNEL_2) = MIX_SOUND_TIMER_SET_194_8125_HZ_VALUE(3117, 16, MM_SW_BUFFERLEN/2);

// Set source length
SCHANNEL_LENGTH(SWM_CHANNEL_1) = MM_SW_BUFFERLEN / 2;
Expand All @@ -154,10 +176,10 @@ static void SetupSWM(void)

mm_startup_wait();

TIMER_DATA(MIX_TIMER_NUMBER) = 0xFD60;
TIMER_CR(MIX_TIMER_NUMBER) = 0x00C2;
timerStart(MIX_TIMER_NUMBER, MIX_TIMER_194_8125_HZ_DIV, MIX_TIMER_SET_194_8125_HZ_VALUE(3117, 16), NULL);
TIMER_CR(MIX_TIMER_NUMBER) |= TIMER_IRQ_REQ;

mmSetResolution(31170);
mmSetResolution(RESOLUTION_194_8125_HZ_VALUE(3117, 16));

// Lock Stream channels
mmLockChannelsQuick((1 << SWM_CHANNEL_1) | (1 << SWM_CHANNEL_2));
Expand Down Expand Up @@ -189,7 +211,7 @@ void mmMixerSetPan(int channel, mm_byte panning)
void mmMixerSetFreq(int channel, mm_word rate)
{
mm_mas_ds_sample *sample = (mm_mas_ds_sample *)(mm_mix_channels[channel].samp + 0x2000000);
mm_word freq = (sample->default_frequency * rate) >> 10;
mm_word freq = ROUND_CLOSEST(sample->default_frequency * rate, 1024);

if (freq >= 0x1FFF)
freq = 0x1FFF;
Expand All @@ -200,7 +222,7 @@ void mmMixerSetFreq(int channel, mm_word rate)
// Multiply channel frequency by a value
void mmMixerMulFreq(int channel, mm_word factor)
{
mm_word freq = ((mm_mix_channels[channel].freq * factor) + (255 * 2)) >> 10;
mm_word freq = ROUND_CLOSEST(mm_mix_channels[channel].freq * factor, 1024);

if (freq >= 0x1FFF)
freq = 0x1FFF;
Expand Down Expand Up @@ -259,10 +281,10 @@ void mmSelectMode(mm_mode_enum mode)
DisableSWM();
ClearAllChannels();
// 256hz resolution
mmSetResolution(40960);
mmSetResolution(RESOLUTION_256_HZ_VALUE(256, 1));

TIMER_DATA(MIX_TIMER_NUMBER) = 0xFF80;
TIMER_CR(MIX_TIMER_NUMBER) = 0x00C3;
timerStart(MIX_TIMER_NUMBER, MIX_TIMER_256_HZ_DIV, MIX_TIMER_SET_256_HZ_VALUE(256, 1), NULL);
TIMER_CR(MIX_TIMER_NUMBER) |= TIMER_IRQ_REQ;

EnableSound();
break;
Expand Down