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1 ;=============================================================================
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2 ;
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3 ; File color_processor.asm
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4 ;
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5 ; Decompress and draw an image.
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6 ;
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7 ; This program is free software: you can redistribute it and/or modify
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8 ; it under the terms of the GNU General Public License as published by
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9 ; the Free Software Foundation, either version 3 of the License, or
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10 ; (at your option) any later version.
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11 ;
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12 ; This program is distributed in the hope that it will be useful,
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13 ; but WITHOUT ANY WARRANTY; without even the implied warranty of
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14 ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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15 ; GNU General Public License for more details.
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16 ;
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17 ; You should have received a copy of the GNU General Public License
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18 ; along with this program. If not, see <http://www.gnu.org/licenses/>.
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19 ;
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20 ; Copyright (c) 2010, JD Gascuel.
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21 ;=============================================================================
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22 ; HISTORY
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23 ; 2010-12-13 : [jDG] Creation
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24 ;
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25 ; RATIONALS: The OSTC have a nice color screen, and a std geek attitude impose
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26 ; to show off ... ;-)
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27 ;
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28 ; Inputs: TBLPTR points to the image description block.
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29 ; win_top, win_leftx2 the Top/Leftx2 corner here to put the image.
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30 ; Ouputs: None.
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31 ; Trashed: TBLPTR, TABLAT, FSR2, PROD, aa_width, aa_height
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32 ;
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33 ; ImageBloc:
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34 ; db widthx2, height
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35 ; db nbColors, 0 ; Unused yet... Should be 0 to keep packing happy.
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36 ; dw color0, color1, color2, color3, ...
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37 ; db ...packed pixels...
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38 ;
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39 ; Limitations:
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40 ; * nbColors should be <= 15.
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41 ; * image width should be even.
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42 ; * image left border should be on even position too.
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43 ; Compressed format:
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44 ; - Upper nibble = color, lower nibble = count-1.
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45 ; - All bytes F* accumulates to make count larger than 16.
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46 ; Eg. 00 is 1 pixel color 0
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47 ; 07 is 8 pixels color 0
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48 ; 70 is 1 pixel color 7
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49 ; bf is 16 pixels of color .11
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50 ; F1 F2 F3 04 is 0x1235 pixels of color 0.
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51 ;
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52 ;Temporary overlay (in bank 0)
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53 img_width equ aa_width
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54 img_height equ aa_height
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55 img_top equ win_top
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56 img_left equ win_leftx2
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57 img_pixelsL equ aa_start+0
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58 img_pixelsH equ aa_start+1
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59 img_pixelsU equ aa_end+0
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60 img_countL equ aa_end+1
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61 img_countH equ aa_colorDiv+0
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62 img_colors equ aa_colorDiv+1
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63 colorTable equ letter
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64
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65 ;-----------------------------------------------------------------------------
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66 ; Make an entry in the link map.
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67 color_processor code
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68
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69 ;-----------------------------------------------------------------------------
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70 color_image:
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71 movlb HIGH(img_width) ; Switch to bank 0.
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72
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73 ;---- Get image parameters -------------------------------------------
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74 tblrd*+
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75 movff TABLAT,img_width
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76 tblrd*+
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77 movff TABLAT,img_height
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78 tblrd*+
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79 movff TABLAT,img_colors
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80 tblrd*+
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81 ;---- Copy color table -----------------------------------------------
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82 movf img_colors,W
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83 lfsr FSR2,colorTable
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84 get_colors_loop:
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85 tblrd*+
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86 movff TABLAT,POSTINC2
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87 tblrd*+
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88 movff TABLAT,POSTINC2
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89 decfsz WREG
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90 bra get_colors_loop
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91
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92 ; Compute width * height * 2 : the number of pixels to write.
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93 clrf img_pixelsU
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94 movf img_width,W ; Compute number of pixels to draw
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95 mulwf img_height ; 0 .. 160x240
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96 bcf STATUS,C ; BEWARE: milw does not reset carry flag !
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97 rlcf PRODL ; x2 --> 0 .. 320x240, might by > 0xFFFF
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98 rlcf PRODH
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99 movff PRODL, img_pixelsL
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100 movff PRODH, img_pixelsH
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101 rlcf img_pixelsU ; Get the upper bit in place.
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102
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103 ;---- Send window command --------------------------------------------
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104 clrf img_width+1 ; x2 on width, for the true box size.
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105 rlcf img_width+0
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106 rlcf img_width+1
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107 call aa_box_cmd
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108 AA_CMD_WRITE 0x22
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109
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110 ;---- Decode pixels --------------------------------------------------
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111 color_image_loop_xy:
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112 ; Get pixel count
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113 clrf img_countL
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114 clrf img_countH
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115
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116 color_image_loop_count:
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117 tblrd*+ ; Get one byte
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118
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119 movlw 0x0F ; Get count bits
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120 andwf TABLAT,W
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121 swapf WREG ; On top-4 bits of W
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122 rlcf WREG ; Push topmost bit into img_count:2
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123 rlcf img_countL
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124 rlcf img_countH
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125 rlcf WREG ; Push topmost bit into img_count:2
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126 rlcf img_countL
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127 rlcf img_countH
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128 rlcf WREG ; Push topmost bit into img_count:2
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129 rlcf img_countL
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130 rlcf img_countH
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131 rlcf WREG ; Push topmost bit into img_count:2
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132 rlcf img_countL
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133 rlcf img_countH
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134
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135 movf TABLAT,W ; Does the color-bits mark a big-count ?
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136 andlw 0xF0
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137 xorlw 0xF0
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138 bz color_image_loop_count ; YES: loop for more count bits.
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139
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140 ; Get pixel color into PROD
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141 xorlw 0xF0 ; Get back index.
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142 swapf WREG ; Get color index to lower bits.
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143 addwf WREG ; x2
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144 addlw LOW(letter) ; 0x60 + 2 * .15 < 0x80.
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145 movff WREG,FSR2L
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146 movff POSTINC2,PRODL
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147 movff POSTINC2,PRODH
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148
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149 ; Substract count-1 from the number of pixel we should do.
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150 movf img_countL,W ; Make a 24bit substraction.
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151 subwf img_pixelsL,F
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152 movf img_countH,W
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153 subwfb img_pixelsH,F
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154 movlw 0
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155 subwfb img_pixelsU,F
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156
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157 incf img_countL ; Get back the true count.
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158 addwfc img_countH
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159
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160 ; Loop sending pixel color
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161 incf img_countH ; Because we decrement first, should add one here !
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162 color_image_loop_pixel:
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163 AA_DATA_WRITE_PROD
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164 decfsz img_countL
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165 bra color_image_loop_pixel
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166 decfsz img_countH
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167 bra color_image_loop_pixel
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168
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169 ; And count (on a 17bit counter)
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170 clrf WREG ; Make a 24bit decrement.
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171 decf img_pixelsL
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172 subwfb img_pixelsH,F
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173 subwfb img_pixelsU,F
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174
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175 movf img_pixelsL,W ; Test if img_pixels == 0
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176 iorwf img_pixelsH,W
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177 iorwf img_pixelsU,W
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178 bnz color_image_loop_xy ; NO: loop...
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179
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180 ;---- Closeup --------------------------------------------------------
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181 AA_CMD_WRITE 0x00
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182 return
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