1 // Megadrive ym2612 interface for eke-eke's genplus-gx ym2612, based on MAME's ym2612
2 // Note: if a mono route is needed (in the future), uncomment in the main render loop.
3
4 #include "burnint.h"
5 #include "burn_md2612.h"
6
7 void (*BurnMD2612Update)(INT16* pSoundBuf, INT32 nSegmentEnd);
8
9 static INT32 (*BurnMD2612StreamCallback)(INT32 nSoundRate);
10
11 static INT32 nBurnMD2612SoundRate;
12
13 static INT16* pBuffer;
14 static INT16* pMD2612Buffer[2];
15
16 static INT32 nMD2612Position;
17
18 static UINT32 nSampleSize;
19 static INT32 nFractionalPosition;
20
21 static INT32 nNumChips = 0;
22 static INT32 bMD2612AddSignal;
23
24 static double MD2612Volumes[2];
25 static INT32 MD2612RouteDirs[2];
26
27 // ----------------------------------------------------------------------------
28 // Dummy functions
29
MD2612UpdateDummy(INT16 *,INT32)30 static void MD2612UpdateDummy(INT16*, INT32)
31 {
32 return;
33 }
34
MD2612StreamCallbackDummy(INT32)35 static INT32 MD2612StreamCallbackDummy(INT32)
36 {
37 return 0;
38 }
39
40 // ----------------------------------------------------------------------------
41 // Execute MD2612 for part of a frame
42
MD2612Render(INT32 nSegmentLength)43 static void MD2612Render(INT32 nSegmentLength)
44 {
45 #if defined FBA_DEBUG
46 if (!DebugSnd_YM2612Initted) bprintf(PRINT_ERROR, _T("MD2612Render called without init\n"));
47 #endif
48
49 if (nMD2612Position >= nSegmentLength) {
50 return;
51 }
52
53 nSegmentLength -= nMD2612Position;
54
55 pMD2612Buffer[0] = pBuffer + 0 * 4096 + 4 + nMD2612Position;
56 pMD2612Buffer[1] = pBuffer + 1 * 4096 + 4 + nMD2612Position;
57
58 MDYM2612Update(&pMD2612Buffer[0], nSegmentLength);
59
60 nMD2612Position += nSegmentLength;
61 }
62
63 // ----------------------------------------------------------------------------
64
65 // Update the sound buffer
66
67 #define INTERPOLATE_ADD_SOUND_LEFT(route, buffer) \
68 if ((MD2612RouteDirs[route] & BURN_SND_ROUTE_LEFT) == BURN_SND_ROUTE_LEFT) { \
69 nLeftSample[0] += (INT32)(pMD2612Buffer[buffer][(nFractionalPosition >> 16) - 3]/* * MD2612Volumes[route]*/); \
70 nLeftSample[1] += (INT32)(pMD2612Buffer[buffer][(nFractionalPosition >> 16) - 2]/* * MD2612Volumes[route]*/); \
71 nLeftSample[2] += (INT32)(pMD2612Buffer[buffer][(nFractionalPosition >> 16) - 1]/* * MD2612Volumes[route]*/); \
72 nLeftSample[3] += (INT32)(pMD2612Buffer[buffer][(nFractionalPosition >> 16) - 0]/* * MD2612Volumes[route]*/); \
73 }
74
75 #define INTERPOLATE_ADD_SOUND_RIGHT(route, buffer) \
76 if ((MD2612RouteDirs[route] & BURN_SND_ROUTE_RIGHT) == BURN_SND_ROUTE_RIGHT) { \
77 nRightSample[0] += (INT32)(pMD2612Buffer[buffer][(nFractionalPosition >> 16) - 3]/* * MD2612Volumes[route]*/); \
78 nRightSample[1] += (INT32)(pMD2612Buffer[buffer][(nFractionalPosition >> 16) - 2]/* * MD2612Volumes[route]*/); \
79 nRightSample[2] += (INT32)(pMD2612Buffer[buffer][(nFractionalPosition >> 16) - 1]/* * MD2612Volumes[route]*/); \
80 nRightSample[3] += (INT32)(pMD2612Buffer[buffer][(nFractionalPosition >> 16) - 0]/* * MD2612Volumes[route]*/); \
81 }
82
MD2612UpdateResample(INT16 * pSoundBuf,INT32 nSegmentEnd)83 static void MD2612UpdateResample(INT16* pSoundBuf, INT32 nSegmentEnd)
84 {
85 #if defined FBA_DEBUG
86 if (!DebugSnd_YM2612Initted) bprintf(PRINT_ERROR, _T("MD2612UpdateResample called without init\n"));
87 #endif
88
89 INT32 nSegmentLength = nSegmentEnd;
90 INT32 nSamplesNeeded = nSegmentEnd * nBurnMD2612SoundRate / nBurnSoundRate + 1;
91
92 if (nSamplesNeeded < nMD2612Position) {
93 nSamplesNeeded = nMD2612Position;
94 }
95
96 if (nSegmentLength > nBurnSoundLen) {
97 nSegmentLength = nBurnSoundLen;
98 }
99 nSegmentLength <<= 1;
100
101 MD2612Render(nSamplesNeeded);
102
103 pMD2612Buffer[0] = pBuffer + 0 * 4096 + 4;
104 pMD2612Buffer[1] = pBuffer + 1 * 4096 + 4;
105
106 for (INT32 i = (nFractionalPosition & 0xFFFF0000) >> 15; i < nSegmentLength; i += 2, nFractionalPosition += nSampleSize) {
107 INT32 nLeftSample[4] = {0, 0, 0, 0};
108 INT32 nRightSample[4] = {0, 0, 0, 0};
109 INT32 nTotalLeftSample, nTotalRightSample;
110
111 INTERPOLATE_ADD_SOUND_LEFT (BURN_SND_MD2612_MD2612_ROUTE_1, 0)
112 //INTERPOLATE_ADD_SOUND_RIGHT (BURN_SND_MD2612_MD2612_ROUTE_1, 0) // uncomment these to fix MONO, if needed in the future. (unlikely)
113 //INTERPOLATE_ADD_SOUND_LEFT (BURN_SND_MD2612_MD2612_ROUTE_2, 1)
114 INTERPOLATE_ADD_SOUND_RIGHT (BURN_SND_MD2612_MD2612_ROUTE_2, 1)
115
116 nTotalLeftSample = INTERPOLATE4PS_16BIT((nFractionalPosition >> 4) & 0x0fff, nLeftSample[0], nLeftSample[1], nLeftSample[2], nLeftSample[3]);
117 nTotalRightSample = INTERPOLATE4PS_16BIT((nFractionalPosition >> 4) & 0x0fff, nRightSample[0], nRightSample[1], nRightSample[2], nRightSample[3]);
118
119 nTotalLeftSample = BURN_SND_CLIP(nTotalLeftSample * MD2612Volumes[BURN_SND_MD2612_MD2612_ROUTE_1]);
120 nTotalRightSample = BURN_SND_CLIP(nTotalRightSample * MD2612Volumes[BURN_SND_MD2612_MD2612_ROUTE_2]);
121
122 if (bMD2612AddSignal) {
123 pSoundBuf[i + 0] = BURN_SND_CLIP(pSoundBuf[i + 0] + nTotalLeftSample);
124 pSoundBuf[i + 1] = BURN_SND_CLIP(pSoundBuf[i + 1] + nTotalRightSample);
125 } else {
126 pSoundBuf[i + 0] = nTotalLeftSample;
127 pSoundBuf[i + 1] = nTotalRightSample;
128 }
129 }
130
131 if (nSegmentEnd >= nBurnSoundLen) {
132 INT32 nExtraSamples = nSamplesNeeded - (nFractionalPosition >> 16);
133
134 for (INT32 i = -4; i < nExtraSamples; i++) {
135 pMD2612Buffer[0][i] = pMD2612Buffer[0][(nFractionalPosition >> 16) + i];
136 pMD2612Buffer[1][i] = pMD2612Buffer[1][(nFractionalPosition >> 16) + i];
137 }
138
139 nFractionalPosition &= 0xFFFF;
140
141 nMD2612Position = nExtraSamples;
142 }
143 }
144
145 // ----------------------------------------------------------------------------
146 // Callbacks for YM2612 core
BurnMD2612UpdateRequest()147 void BurnMD2612UpdateRequest()
148 {
149 #if defined FBA_DEBUG
150 if (!DebugSnd_YM2612Initted) bprintf(PRINT_ERROR, _T("YM2612UpdateRequest called without init\n"));
151 #endif
152
153 MD2612Render(BurnMD2612StreamCallback(nBurnMD2612SoundRate));
154 }
155
156 // ----------------------------------------------------------------------------
157 // Initialisation, etc.
158
BurnMD2612Reset()159 void BurnMD2612Reset()
160 {
161 #if defined FBA_DEBUG
162 if (!DebugSnd_YM2612Initted) bprintf(PRINT_ERROR, _T("BurnMD2612Reset called without init\n"));
163 #endif
164
165 MDYM2612Reset();
166 }
167
BurnMD2612Exit()168 void BurnMD2612Exit()
169 {
170 #if defined FBA_DEBUG
171 if (!DebugSnd_YM2612Initted) bprintf(PRINT_ERROR, _T("BurnMD2612Exit called without init\n"));
172 #endif
173
174 if (!DebugSnd_YM2612Initted) return;
175
176 MDYM2612Exit();
177
178 BurnFree(pBuffer);
179
180 nNumChips = 0;
181 bMD2612AddSignal = 0;
182
183 DebugSnd_YM2612Initted = 0;
184 }
185
BurnMD2612Init(INT32 num,INT32 bIsPal,INT32 (* StreamCallback)(INT32),INT32 bAddSignal)186 INT32 BurnMD2612Init(INT32 num, INT32 bIsPal, INT32 (*StreamCallback)(INT32), INT32 bAddSignal)
187 {
188 if (num > 1) {
189 bprintf(0, _T("BurnMD2612Init(): MD2612 only supports 1 chip!\n"));
190 return 0;
191 }
192
193 DebugSnd_YM2612Initted = 1;
194
195 if (nBurnSoundRate <= 0) {
196 BurnMD2612StreamCallback = MD2612StreamCallbackDummy;
197
198 BurnMD2612Update = MD2612UpdateDummy;
199
200 MDYM2612Init();
201 return 0;
202 }
203
204 BurnMD2612StreamCallback = StreamCallback;
205
206 if (!StreamCallback) {
207 bprintf(0, _T("BurnMD2612Init(): StreamCallback is NULL! Crashing in 3..2...1....\n"));
208 }
209
210 // Megadrive's 2612 runs at 53267hz NTSC, 52781hz PAL
211 nBurnMD2612SoundRate = (bIsPal) ? 52781 : 53267;
212 BurnMD2612Update = MD2612UpdateResample;
213 nSampleSize = (UINT32)nBurnMD2612SoundRate * (1 << 16) / nBurnSoundRate;
214
215 MDYM2612Init();
216
217 pBuffer = (INT16*)BurnMalloc(4096 * 2 * num * sizeof(INT16));
218 memset(pBuffer, 0, 4096 * 2 * num * sizeof(INT16));
219
220 nMD2612Position = 0;
221 nFractionalPosition = 0;
222
223 nNumChips = num;
224 bMD2612AddSignal = bAddSignal;
225
226 // default routes
227 MD2612Volumes[BURN_SND_MD2612_MD2612_ROUTE_1] = 1.00;
228 MD2612Volumes[BURN_SND_MD2612_MD2612_ROUTE_2] = 1.00;
229 MD2612RouteDirs[BURN_SND_MD2612_MD2612_ROUTE_1] = BURN_SND_ROUTE_LEFT;
230 MD2612RouteDirs[BURN_SND_MD2612_MD2612_ROUTE_2] = BURN_SND_ROUTE_RIGHT;
231
232 return 0;
233 }
234
BurnMD2612SetRoute(INT32 nChip,INT32 nIndex,double nVolume,INT32 nRouteDir)235 void BurnMD2612SetRoute(INT32 nChip, INT32 nIndex, double nVolume, INT32 nRouteDir)
236 {
237 #if defined FBA_DEBUG
238 if (!DebugSnd_YM2612Initted) bprintf(PRINT_ERROR, _T("BurnMD2612SetRoute called without init\n"));
239 if (nIndex < 0 || nIndex > 1) bprintf(PRINT_ERROR, _T("BurnMD2612SetRoute called with invalid index %i\n"), nIndex);
240 if (nChip >= nNumChips) bprintf(PRINT_ERROR, _T("BurnMD2612SetRoute called with invalid chip %i\n"), nChip);
241 #endif
242
243 if (nChip == 0) {
244 MD2612Volumes[nIndex] = nVolume;
245 MD2612RouteDirs[nIndex] = nRouteDir;
246 }
247 }
248
BurnMD2612Scan(INT32 nAction,INT32 * pnMin)249 void BurnMD2612Scan(INT32 nAction, INT32* pnMin)
250 {
251 #if defined FBA_DEBUG
252 if (!DebugSnd_YM2612Initted) bprintf(PRINT_ERROR, _T("BurnMD2612Scan called without init\n"));
253 #endif
254
255 if (nAction & ACB_DRIVER_DATA) {
256 SCAN_VAR(nMD2612Position);
257
258 if (nAction & ACB_WRITE) {
259 MDYM2612LoadContext();
260
261 nMD2612Position = 0;
262 nFractionalPosition = 0;
263 memset(pBuffer, 0, 4096 * 2 * 1 * sizeof(INT16));
264 } else {
265 MDYM2612SaveContext();
266 }
267 }
268 }
269