93 lines
2.4 KiB
C
93 lines
2.4 KiB
C
/*
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============================================================================
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SM8521 sound emulator
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by cam900
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This file is licensed under zlib license.
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============================================================================
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zlib License
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(C) 2023-present cam900 and contributors
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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============================================================================
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TODO:
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- needs hardware test
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*/
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#ifndef _SM8521_EMU_H
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#define _SM8521_EMU_H
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#ifdef __cplusplus
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extern "C"
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{
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#endif
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struct sm8521_sg_t
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{
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unsigned short t; // Time constant register
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unsigned char level; // Output level control register
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signed short out; // output
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int counter; // clock counter
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};
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struct sm8521_wave_t
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{
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struct sm8521_sg_t base;
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unsigned char addr; // waveform address
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unsigned char wave[16]; // 4 bit waveform (32 nybbles)
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};
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struct sm8521_noise_t
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{
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struct sm8521_sg_t base;
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unsigned int lfsr; // LFSR
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};
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struct sm8521_t
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{
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struct sm8521_wave_t sg[2];
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struct sm8521_noise_t noise;
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signed short out; // output
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signed char sgda; // D/A direct output register (write only)
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unsigned char sgc; // Control register
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};
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void sm8521_sg_wave_tick(struct sm8521_wave_t *sg, const int cycle);
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void sm8521_noise_tick(struct sm8521_noise_t *noise, const int cycle);
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void sm8521_sound_tick(struct sm8521_t *sm8521, const int cycle);
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void sm8521_reset(struct sm8521_t *sm8521);
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unsigned char sm8521_read(struct sm8521_t *sm8521, const unsigned char a);
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void sm8521_write(struct sm8521_t *sm8521, const unsigned char a, const unsigned char d);
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#ifdef __cplusplus
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} // extern "C"
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#endif
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#endif // _SM8521_EMU_H
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