Mercurial > repos > blastem

comparison psg.c @ 487:c08a4efeee7f opengl

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Update opengl branch from default. Fix build breakage unrelated to merge
author Mike Pavone <pavone@retrodev.com>
date Sat, 26 Oct 2013 22:38:47 -0700
parents 3e1573fa22cf
children b7b7a1cab44a
comparison
equal deleted inserted replaced
449:7696d824489d 487:c08a4efeee7f
1 /*
2 Copyright 2013 Michael Pavone
3 This file is part of BlastEm.
4 BlastEm is free software distributed under the terms of the GNU General Public License version 3 or greater. See COPYING for full license text.
5 */
1 #include "psg.h" 6 #include "psg.h"
2 #include "render.h" 7 #include "render.h"
3 #include <string.h> 8 #include <string.h>
4 #include <stdlib.h> 9 #include <stdlib.h>
5 10
6 void psg_init(psg_context * context, uint32_t sample_rate, uint32_t master_clock, uint32_t clock_div, uint32_t samples_frame) 11 void psg_init(psg_context * context, uint32_t sample_rate, uint32_t master_clock, uint32_t clock_div, uint32_t samples_frame)
7 { 12 {
8 memset(context, 0, sizeof(*context)); 13 memset(context, 0, sizeof(*context));
9 context->audio_buffer = malloc(sizeof(*context->audio_buffer) * samples_frame); 14 context->audio_buffer = malloc(sizeof(*context->audio_buffer) * samples_frame);
10 context->back_buffer = malloc(sizeof(*context->audio_buffer) * samples_frame); 15 context->back_buffer = malloc(sizeof(*context->audio_buffer) * samples_frame);
11 double clock_rate = (double)master_clock / (double)clock_div;
12 context->buffer_inc = ((double)sample_rate / (double)master_clock) * clock_div;
13 context->clock_inc = clock_div; 16 context->clock_inc = clock_div;
17 context->sample_rate = sample_rate;
14 context->samples_frame = samples_frame; 18 context->samples_frame = samples_frame;
19 psg_adjust_master_clock(context, master_clock);
15 for (int i = 0; i < 4; i++) { 20 for (int i = 0; i < 4; i++) {
16 context->volume[i] = 0xF; 21 context->volume[i] = 0xF;
17 } 22 }
23 }
24
25 #define BUFFER_INC_RES 1000000000UL
26
27 void psg_adjust_master_clock(psg_context * context, uint32_t master_clock)
28 {
29 uint64_t old_inc = context->buffer_inc;
30 context->buffer_inc = ((BUFFER_INC_RES * (uint64_t)context->sample_rate) / (uint64_t)master_clock) * (uint64_t)context->clock_inc;
18 } 31 }
19 32
20 void psg_write(psg_context * context, uint8_t value) 33 void psg_write(psg_context * context, uint8_t value)
21 { 34 {
22 if (value & 0x80) { 35 if (value & 0x80) {
63 #define PSG_VOL_DIV 6 76 #define PSG_VOL_DIV 6
64 77
65 //table shamelessly swiped from PSG doc from smspower.org 78 //table shamelessly swiped from PSG doc from smspower.org
66 int16_t volume_table[16] = { 79 int16_t volume_table[16] = {
67 32767/PSG_VOL_DIV, 26028/PSG_VOL_DIV, 20675/PSG_VOL_DIV, 16422/PSG_VOL_DIV, 13045/PSG_VOL_DIV, 10362/PSG_VOL_DIV, 80 32767/PSG_VOL_DIV, 26028/PSG_VOL_DIV, 20675/PSG_VOL_DIV, 16422/PSG_VOL_DIV, 13045/PSG_VOL_DIV, 10362/PSG_VOL_DIV,
68 8231/PSG_VOL_DIV, 6568/PSG_VOL_DIV, 5193/PSG_VOL_DIV, 4125/PSG_VOL_DIV, 3277/PSG_VOL_DIV, 2603/PSG_VOL_DIV, 81 8231/PSG_VOL_DIV, 6568/PSG_VOL_DIV, 5193/PSG_VOL_DIV, 4125/PSG_VOL_DIV, 3277/PSG_VOL_DIV, 2603/PSG_VOL_DIV,
69 2067/PSG_VOL_DIV, 1642/PSG_VOL_DIV, 1304/PSG_VOL_DIV, 0 82 2067/PSG_VOL_DIV, 1642/PSG_VOL_DIV, 1304/PSG_VOL_DIV, 0
70 }; 83 };
71 84
72 void psg_run(psg_context * context, uint32_t cycles) 85 void psg_run(psg_context * context, uint32_t cycles)
73 { 86 {
90 } 103 }
91 } 104 }
92 } 105 }
93 } 106 }
94 context->buffer_fraction += context->buffer_inc; 107 context->buffer_fraction += context->buffer_inc;
95 if (context->buffer_fraction >= 1.0) { 108 if (context->buffer_fraction >= BUFFER_INC_RES) {
96 context->buffer_fraction -= 1.0; 109 context->buffer_fraction -= BUFFER_INC_RES;
97 int16_t acc = 0; 110 int16_t acc = 0;
98 for (int i = 0; i < 3; i++) { 111 for (int i = 0; i < 3; i++) {
99 if (context->output_state[i]) { 112 if (context->output_state[i]) {
100 acc += volume_table[context->volume[i]]; 113 acc += volume_table[context->volume[i]];
101 } 114 }