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1 ; |
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2 ; Copyright (c) 2010 The WebM project authors. All Rights Reserved. |
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3 ; |
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4 ; Use of this source code is governed by a BSD-style license |
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5 ; that can be found in the LICENSE file in the root of the source |
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6 ; tree. An additional intellectual property rights grant can be found |
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7 ; in the file PATENTS. All contributing project authors may |
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8 ; be found in the AUTHORS file in the root of the source tree. |
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9 ; |
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10 |
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11 |
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12 EXPORT |vp8_start_encode| |
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13 EXPORT |vp8_encode_bool| |
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14 EXPORT |vp8_stop_encode| |
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15 EXPORT |vp8_encode_value| |
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16 IMPORT |vp8_validate_buffer_arm| |
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17 |
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18 INCLUDE vp8_asm_enc_offsets.asm |
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19 |
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20 ARM |
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21 REQUIRE8 |
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22 PRESERVE8 |
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23 |
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24 AREA |.text|, CODE, READONLY |
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25 |
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26 ; macro for validating write buffer position |
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27 ; needs vp8_writer in r0 |
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28 ; start shall not be in r1 |
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29 MACRO |
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30 VALIDATE_POS $start, $pos |
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31 push {r0-r3, r12, lr} ; rest of regs are preserved by subroutine call |
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32 ldr r2, [r0, #vp8_writer_buffer_end] |
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33 ldr r3, [r0, #vp8_writer_error] |
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34 mov r1, $pos |
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35 mov r0, $start |
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36 bl vp8_validate_buffer_arm |
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37 pop {r0-r3, r12, lr} |
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38 MEND |
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39 |
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40 ; r0 BOOL_CODER *br |
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41 ; r1 unsigned char *source |
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42 ; r2 unsigned char *source_end |
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43 |vp8_start_encode| PROC |
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44 str r2, [r0, #vp8_writer_buffer_end] |
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45 mov r12, #0 |
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46 mov r3, #255 |
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47 mvn r2, #23 |
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48 str r12, [r0, #vp8_writer_lowvalue] |
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49 str r3, [r0, #vp8_writer_range] |
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50 str r2, [r0, #vp8_writer_count] |
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51 str r12, [r0, #vp8_writer_pos] |
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52 str r1, [r0, #vp8_writer_buffer] |
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53 bx lr |
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54 ENDP |
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55 |
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56 ; r0 BOOL_CODER *br |
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57 ; r1 int bit |
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58 ; r2 int probability |
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59 |vp8_encode_bool| PROC |
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60 push {r4-r10, lr} |
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61 |
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62 mov r4, r2 |
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63 |
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64 ldr r2, [r0, #vp8_writer_lowvalue] |
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65 ldr r5, [r0, #vp8_writer_range] |
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66 ldr r3, [r0, #vp8_writer_count] |
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67 |
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68 sub r7, r5, #1 ; range-1 |
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69 |
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70 cmp r1, #0 |
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71 mul r6, r4, r7 ; ((range-1) * probability) |
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72 |
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73 mov r7, #1 |
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74 add r4, r7, r6, lsr #8 ; 1 + (((range-1) * probability) >> 8) |
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75 |
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76 addne r2, r2, r4 ; if (bit) lowvalue += split |
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77 subne r4, r5, r4 ; if (bit) range = range-split |
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78 |
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79 ; Counting the leading zeros is used to normalize range. |
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80 clz r6, r4 |
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81 sub r6, r6, #24 ; shift |
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82 |
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83 ; Flag is set on the sum of count. This flag is used later |
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84 ; to determine if count >= 0 |
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85 adds r3, r3, r6 ; count += shift |
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86 lsl r5, r4, r6 ; range <<= shift |
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87 bmi token_count_lt_zero ; if(count >= 0) |
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88 |
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89 sub r6, r6, r3 ; offset = shift - count |
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90 sub r4, r6, #1 ; offset-1 |
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91 lsls r4, r2, r4 ; if((lowvalue<<(offset-1)) & 0x80000000 ) |
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92 bpl token_high_bit_not_set |
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93 |
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94 ldr r4, [r0, #vp8_writer_pos] ; x |
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95 sub r4, r4, #1 ; x = w->pos-1 |
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96 b token_zero_while_start |
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97 token_zero_while_loop |
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98 mov r9, #0 |
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99 strb r9, [r7, r4] ; w->buffer[x] =(unsigned char)0 |
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100 sub r4, r4, #1 ; x-- |
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101 token_zero_while_start |
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102 cmp r4, #0 |
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103 ldrge r7, [r0, #vp8_writer_buffer] |
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104 ldrb r1, [r7, r4] |
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105 cmpge r1, #0xff |
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106 beq token_zero_while_loop |
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107 |
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108 ldr r7, [r0, #vp8_writer_buffer] |
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109 ldrb r9, [r7, r4] ; w->buffer[x] |
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110 add r9, r9, #1 |
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111 strb r9, [r7, r4] ; w->buffer[x] + 1 |
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112 token_high_bit_not_set |
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113 rsb r4, r6, #24 ; 24-offset |
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114 ldr r9, [r0, #vp8_writer_buffer] |
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115 lsr r7, r2, r4 ; lowvalue >> (24-offset) |
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116 ldr r4, [r0, #vp8_writer_pos] ; w->pos |
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117 lsl r2, r2, r6 ; lowvalue <<= offset |
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118 mov r6, r3 ; shift = count |
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119 add r1, r4, #1 ; w->pos++ |
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120 bic r2, r2, #0xff000000 ; lowvalue &= 0xffffff |
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121 str r1, [r0, #vp8_writer_pos] |
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122 sub r3, r3, #8 ; count -= 8 |
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123 |
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124 VALIDATE_POS r9, r1 ; validate_buffer at pos |
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125 |
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126 strb r7, [r9, r4] ; w->buffer[w->pos++] |
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127 |
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128 token_count_lt_zero |
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129 lsl r2, r2, r6 ; lowvalue <<= shift |
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130 |
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131 str r2, [r0, #vp8_writer_lowvalue] |
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132 str r5, [r0, #vp8_writer_range] |
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133 str r3, [r0, #vp8_writer_count] |
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134 pop {r4-r10, pc} |
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135 ENDP |
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136 |
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137 ; r0 BOOL_CODER *br |
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138 |vp8_stop_encode| PROC |
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139 push {r4-r10, lr} |
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140 |
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141 ldr r2, [r0, #vp8_writer_lowvalue] |
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142 ldr r5, [r0, #vp8_writer_range] |
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143 ldr r3, [r0, #vp8_writer_count] |
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144 |
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145 mov r10, #32 |
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146 |
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147 stop_encode_loop |
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148 sub r7, r5, #1 ; range-1 |
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149 |
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150 mov r4, r7, lsl #7 ; ((range-1) * 128) |
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151 |
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152 mov r7, #1 |
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153 add r4, r7, r4, lsr #8 ; 1 + (((range-1) * 128) >> 8) |
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154 |
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155 ; Counting the leading zeros is used to normalize range. |
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156 clz r6, r4 |
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157 sub r6, r6, #24 ; shift |
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158 |
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159 ; Flag is set on the sum of count. This flag is used later |
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160 ; to determine if count >= 0 |
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161 adds r3, r3, r6 ; count += shift |
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162 lsl r5, r4, r6 ; range <<= shift |
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163 bmi token_count_lt_zero_se ; if(count >= 0) |
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164 |
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165 sub r6, r6, r3 ; offset = shift - count |
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166 sub r4, r6, #1 ; offset-1 |
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167 lsls r4, r2, r4 ; if((lowvalue<<(offset-1)) & 0x80000000 ) |
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168 bpl token_high_bit_not_set_se |
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169 |
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170 ldr r4, [r0, #vp8_writer_pos] ; x |
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171 sub r4, r4, #1 ; x = w->pos-1 |
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172 b token_zero_while_start_se |
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173 token_zero_while_loop_se |
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174 mov r9, #0 |
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175 strb r9, [r7, r4] ; w->buffer[x] =(unsigned char)0 |
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176 sub r4, r4, #1 ; x-- |
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177 token_zero_while_start_se |
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178 cmp r4, #0 |
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179 ldrge r7, [r0, #vp8_writer_buffer] |
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180 ldrb r1, [r7, r4] |
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181 cmpge r1, #0xff |
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182 beq token_zero_while_loop_se |
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183 |
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184 ldr r7, [r0, #vp8_writer_buffer] |
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185 ldrb r9, [r7, r4] ; w->buffer[x] |
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186 add r9, r9, #1 |
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187 strb r9, [r7, r4] ; w->buffer[x] + 1 |
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188 token_high_bit_not_set_se |
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189 rsb r4, r6, #24 ; 24-offset |
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190 ldr r9, [r0, #vp8_writer_buffer] |
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191 lsr r7, r2, r4 ; lowvalue >> (24-offset) |
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192 ldr r4, [r0, #vp8_writer_pos] ; w->pos |
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193 lsl r2, r2, r6 ; lowvalue <<= offset |
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194 mov r6, r3 ; shift = count |
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195 add r1, r4, #1 ; w->pos++ |
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196 bic r2, r2, #0xff000000 ; lowvalue &= 0xffffff |
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197 str r1, [r0, #vp8_writer_pos] |
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198 sub r3, r3, #8 ; count -= 8 |
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199 |
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200 VALIDATE_POS r9, r1 ; validate_buffer at pos |
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201 |
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202 strb r7, [r9, r4] ; w->buffer[w->pos++] |
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203 |
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204 token_count_lt_zero_se |
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205 lsl r2, r2, r6 ; lowvalue <<= shift |
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206 |
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207 subs r10, r10, #1 |
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208 bne stop_encode_loop |
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209 |
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210 str r2, [r0, #vp8_writer_lowvalue] |
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211 str r5, [r0, #vp8_writer_range] |
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212 str r3, [r0, #vp8_writer_count] |
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213 pop {r4-r10, pc} |
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214 |
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215 ENDP |
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216 |
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217 ; r0 BOOL_CODER *br |
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218 ; r1 int data |
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219 ; r2 int bits |
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220 |vp8_encode_value| PROC |
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221 push {r4-r12, lr} |
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222 |
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223 mov r10, r2 |
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224 |
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225 ldr r2, [r0, #vp8_writer_lowvalue] |
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226 ldr r5, [r0, #vp8_writer_range] |
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227 ldr r3, [r0, #vp8_writer_count] |
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228 |
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229 rsb r4, r10, #32 ; 32-n |
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230 |
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231 ; v is kept in r1 during the token pack loop |
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232 lsl r1, r1, r4 ; r1 = v << 32 - n |
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233 |
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234 encode_value_loop |
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235 sub r7, r5, #1 ; range-1 |
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236 |
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237 ; Decisions are made based on the bit value shifted |
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238 ; off of v, so set a flag here based on this. |
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239 ; This value is refered to as "bb" |
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240 lsls r1, r1, #1 ; bit = v >> n |
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241 mov r4, r7, lsl #7 ; ((range-1) * 128) |
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242 |
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243 mov r7, #1 |
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244 add r4, r7, r4, lsr #8 ; 1 + (((range-1) * 128) >> 8) |
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245 |
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246 addcs r2, r2, r4 ; if (bit) lowvalue += split |
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247 subcs r4, r5, r4 ; if (bit) range = range-split |
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248 |
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249 ; Counting the leading zeros is used to normalize range. |
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250 clz r6, r4 |
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251 sub r6, r6, #24 ; shift |
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252 |
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253 ; Flag is set on the sum of count. This flag is used later |
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254 ; to determine if count >= 0 |
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255 adds r3, r3, r6 ; count += shift |
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256 lsl r5, r4, r6 ; range <<= shift |
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257 bmi token_count_lt_zero_ev ; if(count >= 0) |
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258 |
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259 sub r6, r6, r3 ; offset = shift - count |
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260 sub r4, r6, #1 ; offset-1 |
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261 lsls r4, r2, r4 ; if((lowvalue<<(offset-1)) & 0x80000000 ) |
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262 bpl token_high_bit_not_set_ev |
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263 |
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264 ldr r4, [r0, #vp8_writer_pos] ; x |
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265 sub r4, r4, #1 ; x = w->pos-1 |
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266 b token_zero_while_start_ev |
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267 token_zero_while_loop_ev |
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268 mov r9, #0 |
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269 strb r9, [r7, r4] ; w->buffer[x] =(unsigned char)0 |
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270 sub r4, r4, #1 ; x-- |
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271 token_zero_while_start_ev |
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272 cmp r4, #0 |
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273 ldrge r7, [r0, #vp8_writer_buffer] |
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274 ldrb r11, [r7, r4] |
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275 cmpge r11, #0xff |
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276 beq token_zero_while_loop_ev |
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277 |
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278 ldr r7, [r0, #vp8_writer_buffer] |
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279 ldrb r9, [r7, r4] ; w->buffer[x] |
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280 add r9, r9, #1 |
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281 strb r9, [r7, r4] ; w->buffer[x] + 1 |
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282 token_high_bit_not_set_ev |
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283 rsb r4, r6, #24 ; 24-offset |
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284 ldr r9, [r0, #vp8_writer_buffer] |
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285 lsr r7, r2, r4 ; lowvalue >> (24-offset) |
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286 ldr r4, [r0, #vp8_writer_pos] ; w->pos |
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287 lsl r2, r2, r6 ; lowvalue <<= offset |
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288 mov r6, r3 ; shift = count |
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289 add r11, r4, #1 ; w->pos++ |
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290 bic r2, r2, #0xff000000 ; lowvalue &= 0xffffff |
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291 str r11, [r0, #vp8_writer_pos] |
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292 sub r3, r3, #8 ; count -= 8 |
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293 |
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294 VALIDATE_POS r9, r11 ; validate_buffer at pos |
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295 |
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296 strb r7, [r9, r4] ; w->buffer[w->pos++] |
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297 |
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298 token_count_lt_zero_ev |
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299 lsl r2, r2, r6 ; lowvalue <<= shift |
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300 |
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301 subs r10, r10, #1 |
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302 bne encode_value_loop |
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303 |
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304 str r2, [r0, #vp8_writer_lowvalue] |
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305 str r5, [r0, #vp8_writer_range] |
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306 str r3, [r0, #vp8_writer_count] |
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307 pop {r4-r12, pc} |
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308 ENDP |
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309 |
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310 END |