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- [NEW] Començant a implementar la APU

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This commit is contained in:
Raimon Zamora
2025-01-28 14:02:10 +01:00
parent a617fec42a
commit ab7b26c5e6
2 changed files with 120 additions and 0 deletions
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APU.cpp Normal file
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#include "APU.h"
namespace APU
{
#define apu_enabled (NR52&0x80)
#define DAC1_enabled ((NR12&0xf8)!=0)
struct channel_t
{
bool enabled = false;
uint8_t length_timer = 0;
bool length_timer_expired = true;
bool length_enable = false;
};
channel_t channels[4];
uint8_t NR10 = 0; // 0xff10 - Sound channel 1 sweep
uint8_t NR11 = 0; // 0xff11 - Sound channel 1 length timer & duty cycle
uint8_t NR12 = 0; // 0xff12 - Sound channel 1 volume & envelope
uint8_t NR13 = 0; // 0xff13 - Sound channel 1 period low
uint8_t NR14 = 0; // 0xff14 - Sound channel 1 period high & control
// 0xff15 - Not used?
uint8_t NR21 = 0; // 0xff16 - Sound channel 2 length timer & duty cycle
uint8_t NR22 = 0; // 0xff17 - Sound channel 2 volume & envelope
uint8_t NR23 = 0; // 0xff18 - Sound channel 2 period low
uint8_t NR24 = 0; // 0xff19 - Sound channel 2 period high & control
uint8_t NR30 = 0; // 0xff1a - Sound channel 3 DAC enable
uint8_t NR31 = 0; // 0xff1b - Sound channel 3 length timer
uint8_t NR32 = 0; // 0xff1c - Sound channel 3 output level
uint8_t NR33 = 0; // 0xff1d - Sound channel 3 period low
uint8_t NR34 = 0; // 0xff1e - Sound channel 3 period high & control
// 0xff1f - Not used?
uint8_t NR41 = 0; // 0xff20 - Sound channel 4 length timer
uint8_t NR42 = 0; // 0xff21 - Sound channel 4 volume & envelope
uint8_t NR43 = 0; // 0xff22 - Sound channel 4 frequency & randomness
uint8_t NR44 = 0; // 0xff23 - Sound channel 4 control
uint8_t NR50 = 0; // 0xff24 - Master volume & VIN panning
uint8_t NR51 = 0; // 0xff25 - Sound panning
uint8_t NR52 = 0; // 0xff26 - Sound on/off
// 0xff27-0xff2f - Not used?
uint8_t WaveRAM[16]; // 0xff30-0xff3f
void reset()
{
NR10 = 0;
NR11 = 0;
NR12 = 0;
NR13 = 0;
NR14 = 0;
NR21 = 0;
NR22 = 0;
NR23 = 0;
NR24 = 0;
NR30 = 0;
NR31 = 0;
NR32 = 0;
NR33 = 0;
NR34 = 0;
NR41 = 0;
NR42 = 0;
NR43 = 0;
NR44 = 0;
NR50 = 0;
NR51 = 0;
NR52 = 0;
}
void trigger(uint8_t channel)
{
channels[channel].enabled = true;
// length timer expired is reset
// period divider is set to the contents of NR13 and NR14
// envelope timer is reset
// volume is set to contents of NR12 initial volume
// sweep does several things (check documentation)
}
uint8_t readRegister(uint16_t address)
{
switch(address)
{
case 0xff10: return NR10; break;
case 0xff11: return NR11 & 0xc0; break;
case 0xff12: return NR12; break;
case 0xff13: return 0x00; break;
case 0xff14: return NR14 & 0x40; break;
case 0xff24: return NR50; break;
case 0xff25: return NR51; break;
case 0xff26: return NR52; break;
}
}
void writeRegister(uint16_t address, uint8_t value)
{
if (!apu_enabled && (address!=0xff26)) return;
switch(address)
{
case 0xff10: NR10 = value; break;
case 0xff11: NR11 = value; break;
case 0xff12: NR12 = value; break;
case 0xff13: NR13 = value; break;
case 0xff14: NR14 = value; if (value&0x80) trigger(1); break;
case 0xff24: NR50 = value; break;
case 0xff25: NR51 = value; break;
case 0xff26: if (value&0x80) reset(); NR52 = (value&0x80) | (NR52 & 0x0f); break;
}
}
}

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APU.h Normal file
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#pragma once
#include <stdint.h>
namespace APU
{
uint8_t readRegister(uint16_t address);
void writeRegister(uint16_t address, uint8_t value);
}