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1806 | yogev_ezra | 1 | ; GIF LITE v2.0 by Willow |
2 | ; Written in pure assembler by Ivushkin Andrey aka Willow |
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3 | ; |
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4 | ; This include file will contain functions to handle GIF image format |
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5 | ; |
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6 | ; Created: August 15, 2004 |
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7 | ; Last changed: September 9, 2004 |
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8 | |||
9 | ; Change COLOR_ORDER in your program |
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10 | ; if colors are displayed improperly |
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11 | |||
12 | if ~ (COLOR_ORDER in |
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13 | ; This message may not appear under MenuetOS, so watch... |
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14 | display 'Please define COLOR_ORDER: MENUETOS or OTHER',13,10 |
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15 | end if |
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16 | |||
17 | struc GIF_info |
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18 | { |
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19 | ; .NextImg rd 1 ; used internally |
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20 | .Left rw 1 |
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21 | .Top rw 1 |
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22 | .Width rw 1 |
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23 | .Height rw 1 |
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24 | } |
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25 | |||
26 | _null fix 0x1000 |
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27 | |||
28 | ; **************************************** |
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29 | ; FUNCTION GetGIFinfo - retrieve Nth image info |
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30 | ; **************************************** |
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31 | ; in: |
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32 | ; esi - pointer to image list header |
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33 | ; ecx - image_index (0...img_count-1) |
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34 | ; edi - pointer to GIF_info structure to be filled |
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35 | |||
36 | ; out: |
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37 | ; eax - pointer to RAW data, or 0, if error |
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38 | |||
39 | GetGIFinfo: |
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40 | push esi ecx edi |
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41 | xor eax,eax |
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42 | jecxz .eloop |
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43 | .lp: |
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44 | mov esi,[esi] |
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45 | test esi,esi |
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46 | jz .error |
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47 | loop .lp |
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48 | .eloop: |
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49 | add esi,4 |
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50 | movsd |
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51 | movsd |
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52 | mov eax,esi |
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53 | .error: |
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54 | pop edi ecx esi |
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55 | ret |
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56 | |||
57 | ; **************************************** |
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58 | ; FUNCTION ReadGIF - unpacks GIF image |
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59 | ; **************************************** |
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60 | ; in: |
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61 | ; esi - pointer to GIF file in memory |
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62 | ; edi - pointer to output image list |
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63 | ; eax - pointer to work area (MIN 16 KB!) |
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64 | |||
65 | ; out: |
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66 | ; eax - 0, all OK; |
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67 | ; eax - 1, invalid signature; |
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68 | ; eax >=8, unsupported image attributes |
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69 | ; |
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70 | ; ecx - number of images |
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71 | |||
72 | ReadGIF: |
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73 | push esi edi |
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74 | mov [.table_ptr],eax |
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75 | mov [.cur_info],edi |
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76 | xor eax,eax |
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77 | mov [.globalColor],eax |
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78 | mov [.img_count],eax |
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79 | inc eax |
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80 | cmp dword[esi],'GIF8' |
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81 | jne .er ; signature |
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82 | mov ecx,[esi+0xa] |
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83 | inc eax |
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84 | add esi,0xd |
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85 | mov edi,esi |
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86 | bt ecx,7 |
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87 | jnc .nextblock |
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88 | mov [.globalColor],esi |
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89 | call .Gif_skipmap |
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90 | .nextblock: |
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91 | cmp byte[edi],0x21 |
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92 | jne .noextblock |
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93 | inc edi |
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94 | cmp byte[edi],0xf9 ; Graphic Control Ext |
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95 | jne .no_gc |
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96 | add edi,7 |
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97 | jmp .nextblock |
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98 | .no_gc: |
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99 | cmp byte[edi],0xfe ; Comment Ext |
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100 | jne .no_comm |
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101 | inc edi |
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102 | .block_skip: |
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103 | movzx eax,byte[edi] |
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104 | lea edi,[edi+eax+1] |
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105 | cmp byte[edi],0 |
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106 | jnz .block_skip |
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107 | inc edi |
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108 | jmp .nextblock |
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109 | .no_comm: |
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110 | cmp byte[edi],0xff ; Application Ext |
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111 | jne .nextblock |
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112 | add edi,13 |
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113 | jmp .block_skip |
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114 | .noextblock: |
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115 | cmp byte[edi],0x2c ; image beginning |
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116 | jne .er |
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117 | inc [.img_count] |
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118 | inc edi |
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119 | mov esi,[.cur_info] |
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120 | add esi,4 |
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121 | xchg esi,edi |
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122 | movsd |
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123 | movsd |
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124 | push edi |
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125 | movzx ecx,word[esi] |
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126 | inc esi |
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127 | bt ecx,7 |
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128 | jc .uselocal |
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129 | push [.globalColor] |
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130 | mov edi,esi |
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131 | jmp .setPal |
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132 | .uselocal: |
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133 | call .Gif_skipmap |
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134 | push esi |
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135 | .setPal: |
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136 | movzx ecx,byte[edi] |
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137 | inc ecx |
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138 | mov [.codesize],ecx |
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139 | dec ecx |
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140 | pop [.Palette] |
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141 | lea esi,[edi+1] |
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142 | mov edi,[.table_ptr] |
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143 | xor eax,eax |
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144 | cld |
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145 | lodsb ; eax - block_count |
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146 | add eax,esi |
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147 | mov [.block_ofs],eax |
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148 | mov [.bit_count],8 |
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149 | mov eax,1 |
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150 | shl eax,cl |
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151 | mov [.CC],eax |
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152 | inc eax |
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153 | mov [.EOI],eax |
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154 | lea ecx,[eax-1] |
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155 | mov eax, _null shl 16 |
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156 | .filltable: |
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157 | stosd |
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158 | inc eax |
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159 | loop .filltable |
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160 | pop edi |
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161 | mov [.img_start],edi |
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162 | .reinit: |
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163 | mov edx,[.EOI] |
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164 | inc edx |
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165 | push [.codesize] |
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166 | pop [.compsize] |
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167 | call .Gif_get_sym |
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168 | cmp eax,[.CC] |
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169 | je .reinit |
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170 | call .Gif_output |
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171 | .cycle: |
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172 | movzx ebx,ax |
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173 | call .Gif_get_sym |
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174 | cmp eax,edx |
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175 | jae .notintable |
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176 | cmp eax,[.CC] |
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177 | je .reinit |
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178 | cmp eax,[.EOI] |
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179 | je .end |
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180 | call .Gif_output |
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181 | .add: |
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182 | push eax |
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183 | mov eax,[.table_ptr] |
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184 | mov [eax+edx*4],ebx |
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185 | pop eax |
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186 | cmp edx,0xFFF |
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187 | jae .cycle |
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188 | inc edx |
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189 | bsr ebx,edx |
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190 | cmp ebx,[.compsize] |
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191 | jne .noinc |
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192 | inc [.compsize] |
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193 | .noinc: |
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194 | jmp .cycle |
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195 | .notintable: |
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196 | push eax |
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197 | mov eax,ebx |
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198 | call .Gif_output |
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199 | push ebx |
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200 | movzx eax,bx |
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201 | call .Gif_output |
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202 | pop ebx eax |
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203 | jmp .add |
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204 | .er: |
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205 | pop edi |
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206 | jmp .ex |
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207 | .end: |
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208 | mov eax,[.cur_info] |
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209 | mov [eax],edi |
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210 | mov [.cur_info],edi |
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211 | add esi,2 |
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212 | xchg esi,edi |
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213 | .nxt: |
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214 | cmp byte[edi],0 |
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215 | jnz .continue |
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216 | inc edi |
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217 | jmp .nxt |
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218 | .continue: |
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219 | cmp byte[edi],0x3b |
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220 | jne .nextblock |
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221 | xor eax,eax |
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222 | stosd |
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223 | mov ecx,[.img_count] |
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224 | .ex: |
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225 | pop edi esi |
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226 | ret |
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227 | |||
228 | .Gif_skipmap: |
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229 | ; in: ecx - image descriptor, esi - pointer to colormap |
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230 | ; out: edi - pointer to area after colormap |
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231 | |||
232 | and ecx,111b |
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233 | inc ecx ; color map size |
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234 | mov ebx,1 |
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235 | shl ebx,cl |
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236 | lea ebx,[ebx*2+ebx] |
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237 | lea edi,[esi+ebx] |
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238 | ret |
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239 | |||
240 | .Gif_get_sym: |
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241 | mov ecx,[.compsize] |
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242 | push ecx |
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243 | xor eax,eax |
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244 | .shift: |
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245 | ror byte[esi],1 |
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246 | rcr eax,1 |
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247 | dec [.bit_count] |
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248 | jnz .loop1 |
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249 | inc esi |
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250 | cmp esi,[.block_ofs] |
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251 | jb .noblock |
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252 | push eax |
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253 | xor eax,eax |
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254 | lodsb |
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255 | test eax,eax |
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256 | jnz .nextbl |
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257 | mov eax,[.EOI] |
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258 | sub esi,2 |
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259 | add esp,8 |
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260 | jmp .exx |
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261 | .nextbl: |
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262 | add eax,esi |
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263 | mov [.block_ofs],eax |
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264 | pop eax |
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265 | .noblock: |
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266 | mov [.bit_count],8 |
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267 | .loop1: |
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268 | loop .shift |
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269 | pop ecx |
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270 | rol eax,cl |
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271 | .exx: |
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272 | xor ecx,ecx |
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273 | ret |
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274 | |||
275 | .Gif_output: |
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276 | push esi eax edx |
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277 | mov edx,[.table_ptr] |
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278 | .next: |
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279 | push word[edx+eax*4] |
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280 | mov ax,word[edx+eax*4+2] |
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281 | inc ecx |
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282 | cmp ax,_null |
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283 | jnz .next |
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284 | shl ebx,16 |
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285 | mov bx,[esp] |
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286 | .loop2: |
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287 | pop ax |
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288 | |||
289 | lea esi,[eax+eax*2] |
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290 | add esi,[.Palette] |
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291 | |||
292 | if COLOR_ORDER eq MENUETOS |
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293 | mov esi,[esi] |
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294 | bswap esi |
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295 | shr esi,8 |
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296 | mov [edi],esi |
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297 | add edi,3 |
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298 | else |
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299 | movsw |
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300 | movsb |
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301 | end if |
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302 | |||
303 | loop .loop2 |
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304 | pop edx eax esi |
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305 | ret |
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306 | |||
307 | .globalColor rd 1 |
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308 | .img_count rd 1 |
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309 | .cur_info rd 1 ; image table pointer |
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310 | .img_start rd 1 |
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311 | .codesize rd 1 |
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312 | .compsize rd 1 |
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313 | .bit_count rd 1 |
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314 | .CC rd 1 |
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315 | .EOI rd 1 |
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316 | .Palette rd 1 |
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317 | .block_ofs rd 1 |
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318 | .table_ptr rd 1 |