root / trunk / code / projects / mapping / odometry / encoders.c @ 890
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1 | 884 | justin | #include "encoders.h" |
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2 | 890 | justin | #include "dragonfly_lib.h" |
3 | 884 | justin | #include "spi.h" |
4 | #include "ring_buffer.h" |
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5 | 723 | justin | |
6 | unsigned short int left_data_buf; |
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7 | unsigned short int right_data_buf; |
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8 | char buf_index;
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9 | |||
10 | unsigned short int left_data; |
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11 | unsigned short int right_data; |
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12 | |||
13 | unsigned short int left_data_array[BUFFER_SIZE]; |
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14 | unsigned short int right_data_array[BUFFER_SIZE]; |
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15 | int left_data_idx;
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16 | int right_data_idx;
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17 | |||
18 | int left_dx;
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19 | int right_dx;
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20 | long int timecount; |
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21 | |||
22 | void encoder_recv(char data); |
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23 | |||
24 | //Helper Function Prototypes
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25 | inline void left_data_array_put(unsigned short int value); |
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26 | inline unsigned short int left_data_array_top(void); |
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27 | inline unsigned short int left_data_array_prev(void); |
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28 | inline unsigned short int left_data_array_bottom(void); |
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29 | |||
30 | inline void right_data_array_put(unsigned short int value); |
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31 | inline unsigned short int right_data_array_top(void); |
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32 | inline unsigned short int right_data_array_prev(void); |
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33 | inline unsigned short int right_data_array_bottom(void); |
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34 | |||
35 | //RING_BUFFER_NEW(enc_buffer, BUFFER_SIZE, short int);
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36 | |||
37 | void encoder_init(void){ |
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38 | int i;
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39 | |||
40 | 884 | justin | spi_init(encoder_recv,NULL);
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41 | 723 | justin | buf_index = 0;
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42 | left_data_buf = 0;
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43 | right_data_buf= 0;
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44 | left_data = -1;
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45 | right_data = -1;
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46 | //RING_BUFFER_INIT(enc_buffer,BUFFER_SIZE);
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47 | left_data_idx = 0;
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48 | right_data_idx = 0;
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49 | for(i = 0; i < BUFFER_SIZE; i++) { |
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50 | left_data_array[i] = 0;
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51 | } |
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52 | for(i = 0; i < BUFFER_SIZE; i++) { |
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53 | right_data_array[i] = 0;
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54 | } |
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55 | } |
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56 | |||
57 | int encoder_read(char encoder){ |
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58 | if(encoder==LEFT)
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59 | return left_data;
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60 | else if(encoder==RIGHT) |
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61 | return right_data;
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62 | else return -1; |
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63 | } |
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64 | |||
65 | int encoder_change(char encoder){ |
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66 | return 0; |
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67 | } |
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68 | |||
69 | char encoder_direction(char encoder){ |
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70 | return 0; |
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71 | } |
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72 | |||
73 | int encoder_get_dx(char encoder) { |
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74 | if(encoder==LEFT)
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75 | return left_dx;
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76 | else if(encoder==RIGHT) |
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77 | return right_dx;
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78 | else return -1; |
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79 | } |
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80 | |||
81 | void encoder_rst_dx(char encoder) { |
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82 | if(encoder==LEFT)
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83 | left_dx = 0;
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84 | else if(encoder==RIGHT) |
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85 | right_dx = 0;
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86 | } |
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87 | |||
88 | int encoder_get_tc(void) { |
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89 | return timecount;
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90 | } |
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91 | |||
92 | void encoder_rst_tc(void) { |
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93 | timecount = 0;
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94 | } |
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95 | |||
96 | |||
97 | |||
98 | //Full reads occur every 40 microseconds. This function should be called
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99 | //every 8 microseconds.
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100 | void encoder_recv(char data){ |
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101 | short int dx; |
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102 | |||
103 | //First two bytes are normal.
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104 | if(buf_index < 2) |
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105 | right_data_buf |= (((short)data) << ((1-buf_index)*8)) & (0xFF<<(1-buf_index)); |
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106 | |||
107 | //Second two bytes are skewed by one junk bit at the top.
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108 | else if (buf_index == 2) |
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109 | left_data_buf |= (((short)data) << 9) & (0x7F << 9); |
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110 | |||
111 | else if (buf_index == 3) |
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112 | left_data_buf |= (((short)data) << 1) & (0xFF<<1); |
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113 | //Only want the highest bit.
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114 | else if (buf_index == 4) |
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115 | left_data_buf |= (((short)data)>>7) & 0x1; |
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116 | |||
117 | |||
118 | buf_index = (buf_index + 1) % 5; |
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119 | |||
120 | if(buf_index==0){ |
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121 | if(left_data_buf & (OCF | COF | LIN))
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122 | left_data = INVALID; |
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123 | |||
124 | else if(((left_data_buf & MagINCn) > 0) && ((left_data_buf & MagDECn) > 0)) |
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125 | left_data = MAGNET_FAILURE; |
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126 | |||
127 | else left_data = (left_data_buf>>5) & 1023; |
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128 | |||
129 | if(right_data_buf & (OCF | COF | LIN))
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130 | right_data = INVALID; |
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131 | |||
132 | else if ( ((left_data_buf & MagINCn) > 0) && ((left_data_buf & MagDECn) > 0)) |
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133 | left_data = MAGNET_FAILURE; |
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134 | |||
135 | else right_data = (right_data_buf>>5) & 1023; |
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136 | |||
137 | |||
138 | |||
139 | left_data_buf = 0;
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140 | right_data_buf = 0;
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141 | } |
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142 | |||
143 | |||
144 | if(left_data < INVALID) {
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145 | //Put new data onto data array
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146 | left_data_array_put(left_data); |
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147 | |||
148 | //Adjust left accumulator
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149 | dx = left_data - left_data_array_prev(); |
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150 | if(dx > 5) { //underflow |
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151 | left_dx += dx - 1023;
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152 | } |
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153 | else if(dx < -5) { //overflow |
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154 | left_dx += dx + 1023;
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155 | } |
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156 | else {
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157 | left_dx += dx; |
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158 | } |
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159 | } |
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160 | |||
161 | if(right_data < INVALID) {
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162 | //Put new data onto data array
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163 | right_data_array_put(right_data); |
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164 | |||
165 | //Adjust right accumulator
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166 | dx = right_data - right_data_array_prev(); |
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167 | if(dx > 5) { //underflow |
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168 | right_dx += dx - 1023;
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169 | } |
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170 | else if(dx < -5) { //overflow |
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171 | right_dx += dx + 1023;
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172 | } |
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173 | else {
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174 | right_dx += dx; |
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175 | } |
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176 | } |
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177 | |||
178 | //Increment timecount accumulator
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179 | timecount++; |
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180 | } |
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181 | |||
182 | //Helper Functions
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183 | inline void left_data_array_put(unsigned short int value) { |
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184 | if(left_data_idx == BUFFER_SIZE-1) |
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185 | left_data_idx = 0;
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186 | else
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187 | left_data_idx++; |
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188 | left_data_array[left_data_idx] = value; |
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189 | } |
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190 | |||
191 | inline unsigned short int left_data_array_top(void) { |
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192 | return left_data_array[left_data_idx];
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193 | } |
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194 | |||
195 | inline unsigned short int left_data_array_prev(void) { |
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196 | if(left_data_idx == 0) |
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197 | return left_data_array[BUFFER_SIZE-1]; |
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198 | else
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199 | return left_data_array[left_data_idx - 1]; |
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200 | } |
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201 | |||
202 | inline unsigned short int left_data_array_bottom(void) { |
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203 | if(left_data_idx == BUFFER_SIZE-1) |
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204 | return left_data_array[0]; |
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205 | else
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206 | return left_data_array[left_data_idx + 1]; |
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207 | } |
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208 | |||
209 | inline void right_data_array_put(unsigned short int value) { |
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210 | if(right_data_idx == BUFFER_SIZE-1) |
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211 | right_data_idx = 0;
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212 | else
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213 | right_data_idx++; |
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214 | right_data_array[right_data_idx] = value; |
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215 | } |
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216 | |||
217 | inline unsigned short int right_data_array_top(void) { |
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218 | return right_data_array[right_data_idx];
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219 | } |
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220 | |||
221 | inline unsigned short int right_data_array_prev(void) { |
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222 | if(right_data_idx == 0) |
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223 | return right_data_array[BUFFER_SIZE-1]; |
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224 | else
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225 | return right_data_array[right_data_idx - 1]; |
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226 | } |
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227 | |||
228 | inline unsigned short int right_data_array_bottom(void) { |
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229 | if(right_data_idx == BUFFER_SIZE-1) |
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230 | return right_data_array[0]; |
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231 | else
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232 | return right_data_array[right_data_idx + 1]; |
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233 | } |