diff options
Diffstat (limited to 'ym2612.c')
| -rw-r--r-- | ym2612.c | 120 |
1 files changed, 63 insertions, 57 deletions
@@ -1,3 +1,8 @@ +/* + Copyright 2013 Michael Pavone + This file is part of BlastEm. + BlastEm is free software distributed under the terms of the GNU General Public License version 3 or greater. See COPYING for full license text. +*/ #include <string.h> #include <math.h> #include <stdio.h> @@ -122,6 +127,13 @@ void ym_finalize_log() } } } +#define BUFFER_INC_RES 1000000000UL + +void ym_adjust_master_clock(ym2612_context * context, uint32_t master_clock) +{ + uint64_t old_inc = context->buffer_inc; + context->buffer_inc = ((BUFFER_INC_RES * (uint64_t)context->sample_rate) / (uint64_t)master_clock) * (uint64_t)context->clock_inc; +} void ym_init(ym2612_context * context, uint32_t sample_rate, uint32_t master_clock, uint32_t clock_div, uint32_t sample_limit, uint32_t options) { @@ -129,8 +141,10 @@ void ym_init(ym2612_context * context, uint32_t sample_rate, uint32_t master_clo memset(context, 0, sizeof(*context)); context->audio_buffer = malloc(sizeof(*context->audio_buffer) * sample_limit*2); context->back_buffer = malloc(sizeof(*context->audio_buffer) * sample_limit*2); - context->buffer_inc = ((double)sample_rate / (double)master_clock) * clock_div * 6; + context->sample_rate = sample_rate; context->clock_inc = clock_div * 6; + ym_adjust_master_clock(context, master_clock); + context->sample_limit = sample_limit*2; context->write_cycle = CYCLE_NEVER; for (int i = 0; i < NUM_OPERATORS; i++) { @@ -162,7 +176,7 @@ void ym_init(ym2612_context * context, uint32_t sample_rate, uint32_t master_clo //populate sine table for (int32_t i = 0; i < 512; i++) { double sine = sin( ((double)(i*2+1) / SINE_TABLE_SIZE) * M_PI_2 ); - + //table stores 4.8 fixed pointed representation of the base 2 log sine_table[i] = round_fixed_point(-log2(sine), 8); } @@ -308,7 +322,7 @@ void ym_run(ym2612_context * context, uint32_t to_cycle) } } else { if (first_key_on) { - dfprintf(debug_file, "Changing op %d envelope %d by %d in %s phase\n", op, operator->envelope, envelope_inc, + dfprintf(debug_file, "Changing op %d envelope %d by %d in %s phase\n", op, operator->envelope, envelope_inc, operator->env_phase == PHASE_SUSTAIN ? "sustain" : (operator->env_phase == PHASE_DECAY ? "decay": "release")); } operator->envelope += envelope_inc; @@ -328,7 +342,7 @@ void ym_run(ym2612_context * context, uint32_t to_cycle) context->env_counter++; } } - + //Update Phase Generator uint32_t channel = context->current_op / 4; if (channel != 5 || !context->dac_enable) { @@ -348,7 +362,7 @@ void ym_run(ym2612_context * context, uint32_t to_cycle) } else { lfo_mod >>= 1; } - operator->phase_counter += lfo_mod; + operator->phase_counter += lfo_mod; } int16_t mod = 0; switch (op % 4) @@ -413,7 +427,7 @@ void ym_run(ym2612_context * context, uint32_t to_cycle) dfprintf(debug_file, "op %d, base phase: %d, mod: %d, sine: %d, out: %d\n", op, phase, mod, sine_table[(phase+mod) & 0x1FF], pow_table[sine_table[phase & 0x1FF] + env]); } phase += mod; - + int16_t output = pow_table[sine_table[phase & 0x1FF] + env]; if (phase & 0x200) { output = -output; @@ -446,29 +460,29 @@ void ym_run(ym2612_context * context, uint32_t to_cycle) context->buffer_fraction += context->buffer_inc; if (context->current_op == NUM_OPERATORS) { context->current_op = 0; - if (context->buffer_fraction > 1.0) { - context->buffer_fraction -= 1.0; - context->audio_buffer[context->buffer_pos] = 0; - context->audio_buffer[context->buffer_pos + 1] = 0; - for (int i = 0; i < NUM_CHANNELS; i++) { - int16_t value = context->channels[i].output & 0x3FE0; - if (value & 0x2000) { - value |= 0xC000; - } - if (context->channels[i].logfile) { - fwrite(&value, sizeof(value), 1, context->channels[i].logfile); - } - if (context->channels[i].lr & 0x80) { - context->audio_buffer[context->buffer_pos] += value / YM_VOLUME_DIVIDER; - } - if (context->channels[i].lr & 0x40) { - context->audio_buffer[context->buffer_pos+1] += value / YM_VOLUME_DIVIDER; - } + } + if (context->buffer_fraction > BUFFER_INC_RES) { + context->buffer_fraction -= BUFFER_INC_RES; + context->audio_buffer[context->buffer_pos] = 0; + context->audio_buffer[context->buffer_pos + 1] = 0; + for (int i = 0; i < NUM_CHANNELS; i++) { + int16_t value = context->channels[i].output & 0x3FE0; + if (value & 0x2000) { + value |= 0xC000; + } + if (context->channels[i].logfile) { + fwrite(&value, sizeof(value), 1, context->channels[i].logfile); } - context->buffer_pos += 2; - if (context->buffer_pos == context->sample_limit) { - render_wait_ym(context); + if (context->channels[i].lr & 0x80) { + context->audio_buffer[context->buffer_pos] += value / YM_VOLUME_DIVIDER; } + if (context->channels[i].lr & 0x40) { + context->audio_buffer[context->buffer_pos+1] += value / YM_VOLUME_DIVIDER; + } + } + context->buffer_pos += 2; + if (context->buffer_pos == context->sample_limit) { + render_wait_ym(context); } } } @@ -561,7 +575,7 @@ void ym_update_phase_inc(ym2612_context * context, ym_operator * operator, uint3 } //detune detune = detune_table[channel->keycode][operator->detune & 0x3]; - } + } if (operator->detune & 0x40) { inc -= detune; //this can underflow, mask to 17-bit result @@ -582,9 +596,20 @@ void ym_update_phase_inc(ym2612_context * context, ym_operator * operator, uint3 void ym_data_write(ym2612_context * context, uint8_t value) { - if (context->selected_reg < 0x21 || context->selected_reg > 0xB6 || (context->selected_reg < 0x30 && context->selected_part)) { + if (context->selected_reg >= YM_REG_END) { return; } + if (context->selected_part) { + if (context->selected_reg < YM_PART2_START) { + return; + } + context->part2_regs[context->selected_reg - YM_PART2_START] = value; + } else { + if (context->selected_reg < YM_PART1_START) { + return; + } + context->part1_regs[context->selected_reg - YM_PART1_START] = value; + } dfprintf(debug_file, "write of %X to reg %X in part %d\n", value, context->selected_reg, context->selected_part+1); if (context->selected_reg < 0x30) { //Shared regs @@ -600,7 +625,7 @@ void ym_data_write(ym2612_context * context, uint8_t value) context->lfo_am_step = context->lfo_pm_step = 0; } context->lfo_freq = value & 0x7; - + break; case REG_TIMERA_HIGH: context->timer_a_load &= 0x3; @@ -644,11 +669,13 @@ void ym_data_write(ym2612_context * context, uint8_t value) } for (uint8_t op = channel * 4, bit = 0x10; op < (channel + 1) * 4; op++, bit <<= 1) { if (value & bit) { - first_key_on = 1; - //printf("Key On for operator %d in channel %d\n", op, channel); - context->operators[op].phase_counter = 0; - context->operators[op].env_phase = PHASE_ATTACK; - context->operators[op].envelope = MAX_ENVELOPE; + if (context->operators[op].env_phase == PHASE_RELEASE) + { + first_key_on = 1; + //printf("Key On for operator %d in channel %d\n", op, channel); + context->operators[op].phase_counter = 0; + context->operators[op].env_phase = PHASE_ATTACK; + } } else { //printf("Key Off for operator %d in channel %d\n", op, channel); context->operators[op].env_phase = PHASE_RELEASE; @@ -753,7 +780,7 @@ void ym_data_write(ym2612_context * context, uint8_t value) } } } - + context->write_cycle = context->current_cycle; context->status |= 0x80; } @@ -763,24 +790,3 @@ uint8_t ym_read_status(ym2612_context * context) return context->status; } -#define GST_YM_OFFSET 0x1E4 -#define GST_YM_SIZE (0x3E4-GST_YM_OFFSET) - -uint8_t ym_load_gst(ym2612_context * context, FILE * gstfile) -{ - uint8_t regdata[GST_YM_SIZE]; - fseek(gstfile, GST_YM_OFFSET, SEEK_SET); - if (fread(regdata, 1, sizeof(regdata), gstfile) != sizeof(regdata)) { - return 0; - } - for (int i = 0; i < sizeof(regdata); i++) { - if (i & 0x100) { - ym_address_write_part2(context, i & 0xFF); - } else { - ym_address_write_part1(context, i); - } - ym_data_write(context, regdata[i]); - } - return 1; -} - |