furnace/src/engine/platform/sound/ymz280b.h

105 lines
3.4 KiB
C++

// license:BSD-3-Clause
// copyright-holders:Aaron Giles
/**********************************************************************************************
*
* Yamaha YMZ280B driver
* by Aaron Giles
*
**********************************************************************************************/
#include <memory>
#ifndef MAME_SOUND_YMZ280B_H
#define MAME_SOUND_YMZ280B_H
#pragma once
namespace ymz280b
{
typedef unsigned char u8;
typedef signed char s8;
typedef unsigned short u16;
typedef signed short s16;
typedef unsigned int u32;
typedef signed int s32;
typedef signed int offs_t;
}
using namespace ymz280b;
class ymz280b_device
{
public:
ymz280b_device();
u8 read(offs_t offset);
void write(offs_t offset, u8 data);
void device_start(u8 *ext_mem);
void device_reset();
void sound_stream_update(s16 **outputs, int samples);
private:
/* struct describing a single playing ADPCM voice */
struct YMZ280BVoice
{
u8 playing; /* 1 if we are actively playing */
bool ended; /* indicate voice has ended in case samples_left is 0 */
u8 keyon; /* 1 if the key is on */
u8 looping; /* 1 if looping is enabled */
u8 mode; /* current playback mode */
u16 fnum; /* frequency */
u8 level; /* output level */
u8 pan; /* panning */
u32 start; /* start address, in nibbles */
u32 stop; /* stop address, in nibbles */
u32 loop_start; /* loop start address, in nibbles */
u32 loop_end; /* loop end address, in nibbles */
u32 position; /* current position, in nibbles */
s32 signal; /* current ADPCM signal */
s32 step; /* current ADPCM step */
s32 loop_signal; /* signal at loop start */
s32 loop_step; /* step at loop start */
u32 loop_count; /* number of loops so far */
s32 output_left; /* output volume (left) */
s32 output_right; /* output volume (right) */
s32 output_step; /* step value for frequency conversion */
s32 output_pos; /* current fractional position */
s16 last_sample; /* last sample output */
s16 curr_sample; /* current sample target */
u8 irq_schedule; /* 1 if the IRQ state is updated by timer */
};
void update_step(struct YMZ280BVoice *voice);
void update_volumes(struct YMZ280BVoice *voice);
int generate_adpcm(struct YMZ280BVoice *voice, s16 *buffer, int samples);
int generate_pcm8(struct YMZ280BVoice *voice, s16 *buffer, int samples);
int generate_pcm16(struct YMZ280BVoice *voice, s16 *buffer, int samples);
void write_to_register(int data);
int compute_status();
// internal state
struct YMZ280BVoice m_voice[8]; /* the 8 voices */
u8 m_current_register; /* currently accessible register */
u8 m_status_register; /* current status register */
u8 m_irq_mask; /* current IRQ mask */
u8 m_irq_enable; /* current IRQ enable */
u8 m_keyon_enable; /* key on enable */
u8 m_ext_mem_enable; /* external memory enable */
u8 m_ext_readlatch; /* external memory prefetched data */
u32 m_ext_mem_address_hi;
u32 m_ext_mem_address_mid;
u32 m_ext_mem_address; /* where the CPU can read the ROM */
u8 *m_ext_mem;
std::unique_ptr<s16[]> m_scratch;
};
#endif // MAME_SOUND_YMZ280B_H