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1 /* |
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2 * GUSEMU32 - mixing engine (similar to Interwave GF1 compatibility) |
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3 * |
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4 * Copyright (C) 2000-2007 Tibor "TS" Schütz |
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5 * |
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6 * Permission is hereby granted, free of charge, to any person obtaining a copy |
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7 * of this software and associated documentation files (the "Software"), to deal |
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8 * in the Software without restriction, including without limitation the rights |
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9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
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10 * copies of the Software, and to permit persons to whom the Software is |
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11 * furnished to do so, subject to the following conditions: |
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12 * |
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13 * The above copyright notice and this permission notice shall be included in |
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14 * all copies or substantial portions of the Software. |
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15 * |
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16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
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19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
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21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
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22 * THE SOFTWARE. |
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23 */ |
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24 |
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25 #include "gusemu.h" |
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26 #include "gustate.h" |
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27 |
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28 #define GUSregb(position) (* (gusptr+(position))) |
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29 #define GUSregw(position) (*(GUSword *) (gusptr+(position))) |
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30 #define GUSregd(position) (*(GUSdword *)(gusptr+(position))) |
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31 |
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32 #define GUSvoice(position) (*(GUSword *)(voiceptr+(position))) |
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33 |
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34 /* samples are always 16bit stereo (4 bytes each, first right then left interleaved) */ |
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35 void gus_mixvoices(GUSEmuState * state, unsigned int playback_freq, unsigned int numsamples, |
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36 GUSsample *bufferpos) |
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37 { |
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38 /* note that byte registers are stored in the upper half of each voice register! */ |
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39 GUSbyte *gusptr; |
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40 int Voice; |
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41 GUSword *voiceptr; |
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42 |
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43 unsigned int count; |
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44 for (count = 0; count < numsamples * 2; count++) |
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45 *(bufferpos + count) = 0; /* clear */ |
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46 |
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47 gusptr = state->gusdatapos; |
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48 voiceptr = (GUSword *) gusptr; |
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49 if (!(GUSregb(GUS4cReset) & 0x01)) /* reset flag active? */ |
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50 return; |
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51 |
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52 for (Voice = 0; Voice <= (GUSregb(NumVoices) & 31); Voice++) |
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53 { |
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54 if (GUSvoice(wVSRControl) & 0x200) |
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55 GUSvoice(wVSRControl) |= 0x100; /* voice stop request */ |
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56 if (GUSvoice(wVSRVolRampControl) & 0x200) |
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57 GUSvoice(wVSRVolRampControl) |= 0x100; /* Volume ramp stop request */ |
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58 if (!(GUSvoice(wVSRControl) & GUSvoice(wVSRVolRampControl) & 0x100)) /* neither voice nor volume calculation active - save some time here ;) */ |
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59 { |
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60 unsigned int sample; |
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61 |
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62 unsigned int LoopStart = (GUSvoice(wVSRLoopStartHi) << 16) | GUSvoice(wVSRLoopStartLo); /* 23.9 format */ |
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63 unsigned int LoopEnd = (GUSvoice(wVSRLoopEndHi) << 16) | GUSvoice(wVSRLoopEndLo); /* 23.9 format */ |
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64 unsigned int CurrPos = (GUSvoice(wVSRCurrPosHi) << 16) | GUSvoice(wVSRCurrPosLo); /* 23.9 format */ |
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65 int VoiceIncrement = ((((unsigned long) GUSvoice(wVSRFreq) * 44100) / playback_freq) * (14 >> 1)) / |
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66 ((GUSregb(NumVoices) & 31) + 1); /* 6.10 increment/frame to 23.9 increment/sample */ |
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67 |
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68 int PanningPos = (GUSvoice(wVSRPanning) >> 8) & 0xf; |
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69 |
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70 unsigned int Volume32 = 32 * GUSvoice(wVSRCurrVol); /* 32 times larger than original gus for maintaining precision while ramping */ |
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71 unsigned int StartVol32 = (GUSvoice(wVSRVolRampStartVol) & 0xff00) * 32; |
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72 unsigned int EndVol32 = (GUSvoice(wVSRVolRampEndVol) & 0xff00) * 32; |
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73 int VolumeIncrement32 = (32 * 16 * (GUSvoice(wVSRVolRampRate) & 0x3f00) >> 8) >> ((((GUSvoice(wVSRVolRampRate) & 0xc000) >> 8) >> 6) * 3); /* including 1/8/64/512 volume speed divisor */ |
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74 VolumeIncrement32 = (((VolumeIncrement32 * 44100 / 2) / playback_freq) * 14) / ((GUSregb(NumVoices) & 31) + 1); /* adjust ramping speed to playback speed */ |
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75 |
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76 if (GUSvoice(wVSRControl) & 0x4000) |
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77 VoiceIncrement = -VoiceIncrement; /* reverse playback */ |
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78 if (GUSvoice(wVSRVolRampControl) & 0x4000) |
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79 VolumeIncrement32 = -VolumeIncrement32; /* reverse ramping */ |
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80 |
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81 for (sample = 0; sample < numsamples; sample++) |
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82 { |
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83 int sample1, sample2, Volume; |
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84 if (GUSvoice(wVSRControl) & 0x400) /* 16bit */ |
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85 { |
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86 int offset = ((CurrPos >> 9) & 0xc0000) + (((CurrPos >> 9) & 0x1ffff) << 1); |
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87 GUSchar *adr; |
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88 adr = (GUSchar *) state->himemaddr + offset; |
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89 sample1 = (*adr & 0xff) + (*(adr + 1) * 256); |
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90 sample2 = (*(adr + 2) & 0xff) + (*(adr + 2 + 1) * 256); |
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91 } |
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92 else /* 8bit */ |
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93 { |
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94 int offset = (CurrPos >> 9) & 0xfffff; |
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95 GUSchar *adr; |
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96 adr = (GUSchar *) state->himemaddr + offset; |
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97 sample1 = (*adr) * 256; |
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98 sample2 = (*(adr + 1)) * 256; |
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99 } |
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100 |
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101 Volume = ((((Volume32 >> (4 + 5)) & 0xff) + 256) << (Volume32 >> ((4 + 8) + 5))) / 512; /* semi-logarithmic volume, +5 due to additional precision */ |
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102 sample1 = (((sample1 * Volume) >> 16) * (512 - (CurrPos % 512))) / 512; |
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103 sample2 = (((sample2 * Volume) >> 16) * (CurrPos % 512)) / 512; |
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104 sample1 += sample2; |
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105 |
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106 if (!(GUSvoice(wVSRVolRampControl) & 0x100)) |
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107 { |
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108 Volume32 += VolumeIncrement32; |
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109 if ((GUSvoice(wVSRVolRampControl) & 0x4000) ? (Volume32 <= StartVol32) : (Volume32 >= EndVol32)) /* ramp up boundary cross */ |
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110 { |
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111 if (GUSvoice(wVSRVolRampControl) & 0x2000) |
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112 GUSvoice(wVSRVolRampControl) |= 0x8000; /* volramp IRQ enabled? -> IRQ wait flag */ |
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113 if (GUSvoice(wVSRVolRampControl) & 0x800) /* loop enabled */ |
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114 { |
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115 if (GUSvoice(wVSRVolRampControl) & 0x1000) /* bidir. loop */ |
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116 { |
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117 GUSvoice(wVSRVolRampControl) ^= 0x4000; /* toggle dir */ |
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118 VolumeIncrement32 = -VolumeIncrement32; |
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119 } |
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120 else |
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121 Volume32 = (GUSvoice(wVSRVolRampControl) & 0x4000) ? EndVol32 : StartVol32; /* unidir. loop ramp */ |
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122 } |
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123 else |
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124 { |
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125 GUSvoice(wVSRVolRampControl) |= 0x100; |
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126 Volume32 = |
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127 (GUSvoice(wVSRVolRampControl) & 0x4000) ? StartVol32 : EndVol32; |
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128 } |
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129 } |
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130 } |
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131 if ((GUSvoice(wVSRVolRampControl) & 0xa000) == 0xa000) /* volramp IRQ set and enabled? */ |
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132 { |
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133 GUSregd(voicevolrampirq) |= 1 << Voice; /* set irq slot */ |
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134 } |
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135 else |
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136 { |
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137 GUSregd(voicevolrampirq) &= (~(1 << Voice)); /* clear irq slot */ |
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138 GUSvoice(wVSRVolRampControl) &= 0x7f00; |
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139 } |
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140 |
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141 if (!(GUSvoice(wVSRControl) & 0x100)) |
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142 { |
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143 CurrPos += VoiceIncrement; |
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144 if ((GUSvoice(wVSRControl) & 0x4000) ? (CurrPos <= LoopStart) : (CurrPos >= LoopEnd)) /* playback boundary cross */ |
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145 { |
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146 if (GUSvoice(wVSRControl) & 0x2000) |
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147 GUSvoice(wVSRControl) |= 0x8000; /* voice IRQ enabled -> IRQ wait flag */ |
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148 if (GUSvoice(wVSRControl) & 0x800) /* loop enabled */ |
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149 { |
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150 if (GUSvoice(wVSRControl) & 0x1000) /* pingpong loop */ |
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151 { |
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152 GUSvoice(wVSRControl) ^= 0x4000; /* toggle dir */ |
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153 VoiceIncrement = -VoiceIncrement; |
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154 } |
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155 else |
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156 CurrPos = (GUSvoice(wVSRControl) & 0x4000) ? LoopEnd : LoopStart; /* unidir. loop */ |
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157 } |
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158 else if (!(GUSvoice(wVSRVolRampControl) & 0x400)) |
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159 GUSvoice(wVSRControl) |= 0x100; /* loop disabled, rollover check */ |
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160 } |
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161 } |
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162 if ((GUSvoice(wVSRControl) & 0xa000) == 0xa000) /* wavetable IRQ set and enabled? */ |
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163 { |
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164 GUSregd(voicewavetableirq) |= 1 << Voice; /* set irq slot */ |
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165 } |
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166 else |
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167 { |
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168 GUSregd(voicewavetableirq) &= (~(1 << Voice)); /* clear irq slot */ |
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169 GUSvoice(wVSRControl) &= 0x7f00; |
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170 } |
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171 |
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172 /* mix samples into buffer */ |
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173 *(bufferpos + 2 * sample) += (GUSsample) ((sample1 * PanningPos) >> 4); /* right */ |
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174 *(bufferpos + 2 * sample + 1) += (GUSsample) ((sample1 * (15 - PanningPos)) >> 4); /* left */ |
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175 } |
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176 /* write back voice and volume */ |
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177 GUSvoice(wVSRCurrVol) = Volume32 / 32; |
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178 GUSvoice(wVSRCurrPosHi) = CurrPos >> 16; |
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179 GUSvoice(wVSRCurrPosLo) = CurrPos & 0xffff; |
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180 } |
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181 voiceptr += 16; /* next voice */ |
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182 } |
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183 } |
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184 |
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185 void gus_irqgen(GUSEmuState * state, unsigned int elapsed_time) |
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186 /* time given in microseconds */ |
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187 { |
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188 int requestedIRQs = 0; |
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189 GUSbyte *gusptr; |
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190 gusptr = state->gusdatapos; |
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191 if (GUSregb(TimerDataReg2x9) & 1) /* start timer 1 (80us decrement rate) */ |
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192 { |
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193 unsigned int timer1fraction = state->timer1fraction; |
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194 int newtimerirqs; |
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195 newtimerirqs = (elapsed_time + timer1fraction) / (80 * (256 - GUSregb(GUS46Counter1))); |
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196 state->timer1fraction = (elapsed_time + timer1fraction) % (80 * (256 - GUSregb(GUS46Counter1))); |
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197 if (newtimerirqs) |
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198 { |
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199 if (!(GUSregb(TimerDataReg2x9) & 0x40)) |
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200 GUSregb(TimerStatus2x8) |= 0xc0; /* maskable bits */ |
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201 if (GUSregb(GUS45TimerCtrl) & 4) /* timer1 irq enable */ |
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202 { |
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203 GUSregb(TimerStatus2x8) |= 4; /* nonmaskable bit */ |
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204 GUSregb(IRQStatReg2x6) |= 4; /* timer 1 irq pending */ |
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205 GUSregw(TimerIRQs) += newtimerirqs; |
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206 requestedIRQs += newtimerirqs; |
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207 } |
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208 } |
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209 } |
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210 if (GUSregb(TimerDataReg2x9) & 2) /* start timer 2 (320us decrement rate) */ |
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211 { |
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212 unsigned int timer2fraction = state->timer2fraction; |
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213 int newtimerirqs; |
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214 newtimerirqs = (elapsed_time + timer2fraction) / (320 * (256 - GUSregb(GUS47Counter2))); |
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215 state->timer2fraction = (elapsed_time + timer2fraction) % (320 * (256 - GUSregb(GUS47Counter2))); |
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216 if (newtimerirqs) |
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217 { |
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218 if (!(GUSregb(TimerDataReg2x9) & 0x20)) |
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219 GUSregb(TimerStatus2x8) |= 0xa0; /* maskable bits */ |
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220 if (GUSregb(GUS45TimerCtrl) & 8) /* timer2 irq enable */ |
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221 { |
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222 GUSregb(TimerStatus2x8) |= 2; /* nonmaskable bit */ |
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223 GUSregb(IRQStatReg2x6) |= 8; /* timer 2 irq pending */ |
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224 GUSregw(TimerIRQs) += newtimerirqs; |
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225 requestedIRQs += newtimerirqs; |
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226 } |
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227 } |
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228 } |
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229 if (GUSregb(GUS4cReset) & 0x4) /* synth IRQ enable */ |
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230 { |
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231 if (GUSregd(voicewavetableirq)) |
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232 GUSregb(IRQStatReg2x6) |= 0x20; |
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233 if (GUSregd(voicevolrampirq)) |
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234 GUSregb(IRQStatReg2x6) |= 0x40; |
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235 } |
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236 if ((!requestedIRQs) && GUSregb(IRQStatReg2x6)) |
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237 requestedIRQs++; |
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238 if (GUSregb(IRQStatReg2x6)) |
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239 GUSregw(BusyTimerIRQs) = GUS_irqrequest(state, state->gusirq, requestedIRQs); |
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240 } |