1 | ; File name : DisplayContext.asm |
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2 | ; Project name : Assembly Library |
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3 | ; Created date : 25.6.2010 |
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4 | ; Last update : 11.10.2010 |
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5 | ; Author : Tomi Tilli |
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6 | ; Description : Functions for managing display context. |
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7 | |
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8 | ; Section containing code |
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9 | SECTION .text |
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10 | |
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11 | ;-------------------------------------------------------------------- |
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12 | ; DisplayContext_Initialize |
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13 | ; Parameters: |
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14 | ; DS: BDA segment (zero) |
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15 | ; Returns: |
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16 | ; Nothing |
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17 | ; Corrupts registers: |
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18 | ; AX, DX, DI |
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19 | ;-------------------------------------------------------------------- |
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20 | ALIGN JUMP_ALIGN |
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21 | DisplayContext_Initialize: |
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22 | call .DetectAndSetDisplaySegment ; and .InitializeFlags |
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23 | mov WORD [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.fnCharOut], DEFAULT_CHARACTER_OUTPUT |
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24 | mov WORD [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.wCursorShape], CURSOR_NORMAL |
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25 | mov BYTE [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.bAttribute], SCREEN_BACKGROUND_ATTRIBUTE |
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26 | xor ax, ax |
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27 | call DisplayCursor_SetCoordinatesFromAX |
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28 | jmp DisplayContext_SynchronizeToHardware |
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29 | |
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30 | ;-------------------------------------------------------------------- |
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31 | ; .DetectAndSetDisplaySegment |
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32 | ; Parameters: |
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33 | ; DS: BDA segment (zero) |
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34 | ; Returns: |
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35 | ; Nothing |
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36 | ; Corrupts registers: |
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37 | ; AX, DX |
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38 | ;-------------------------------------------------------------------- |
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39 | .DetectAndSetDisplaySegment: |
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40 | mov ax, COLOR_TEXT_SEGMENT |
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41 | cmp BYTE [VIDEO_BDA.bMode], MDA_TEXT_MODE |
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42 | jne SHORT .StoreSegmentToDisplayContext |
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43 | mov ax, MONO_TEXT_SEGMENT |
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44 | .StoreSegmentToDisplayContext: |
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45 | mov [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.fpCursorPosition+2], ax |
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46 | ; Fall to InitializeFlags |
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47 | |
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48 | ;-------------------------------------------------------------------- |
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49 | ; .InitializeFlags |
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50 | ; Parameters: |
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51 | ; DS: BDA segment (zero) |
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52 | ; Returns: |
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53 | ; Nothing |
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54 | ; Corrupts registers: |
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55 | ; AX, DX |
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56 | ;-------------------------------------------------------------------- |
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57 | .InitializeFlags: |
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58 | mov dl, FLG_CONTEXT_ATTRIBUTES |
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59 | call CgaSnow_IsCgaPresent |
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60 | jnc SHORT .DoNotSetCgaFlag |
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61 | or dl, FLG_CONTEXT_CGA |
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62 | .DoNotSetCgaFlag: |
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63 | mov [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.bFlags], dl |
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64 | ret |
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65 | |
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66 | |
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67 | ;-------------------------------------------------------------------- |
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68 | ; DisplayContext_Push |
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69 | ; Parameters: |
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70 | ; Nothing |
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71 | ; Returns: |
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72 | ; Nothing |
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73 | ; Corrupts registers: |
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74 | ; AX, DI |
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75 | ;-------------------------------------------------------------------- |
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76 | ALIGN JUMP_ALIGN |
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77 | DisplayContext_Push: |
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78 | mov di, ds ; Backup DS |
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79 | LOAD_BDA_SEGMENT_TO ds, ax |
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80 | pop ax ; Pop return address |
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81 | |
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82 | %assign i 0 |
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83 | %rep DISPLAY_CONTEXT_size / 2 |
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84 | push WORD [VIDEO_BDA.displayContext + i] |
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85 | %assign i i+2 |
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86 | %endrep |
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87 | |
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88 | mov ds, di ; Restore DS |
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89 | jmp ax |
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90 | |
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91 | ;-------------------------------------------------------------------- |
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92 | ; DisplayContext_Pop |
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93 | ; Parameters: |
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94 | ; Nothing |
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95 | ; Returns: |
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96 | ; Nothing |
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97 | ; Corrupts registers: |
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98 | ; AX, DI |
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99 | ;-------------------------------------------------------------------- |
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100 | ALIGN JUMP_ALIGN |
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101 | DisplayContext_Pop: |
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102 | mov di, ds ; Backup DS |
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103 | LOAD_BDA_SEGMENT_TO ds, ax |
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104 | pop ax ; Pop return address |
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105 | |
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106 | %assign i DISPLAY_CONTEXT_size-2 |
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107 | %rep DISPLAY_CONTEXT_size / 2 |
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108 | pop WORD [VIDEO_BDA.displayContext + i] |
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109 | %assign i i-2 |
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110 | %endrep |
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111 | |
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112 | push ax ; Push return address |
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113 | push dx |
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114 | call DisplayContext_SynchronizeToHardware |
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115 | pop dx |
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116 | mov ds, di ; Restore DS |
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117 | ret |
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118 | |
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119 | |
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120 | ;-------------------------------------------------------------------- |
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121 | ; DisplayContext_PrepareOffScreenBufferInESBXwithLengthInCX |
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122 | ; Parameters: |
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123 | ; CX: Off screen buffer length in characters |
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124 | ; ES:BX: Ptr to off screen buffer |
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125 | ; Returns: |
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126 | ; Nothing |
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127 | ; Corrupts registers: |
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128 | ; AX, DI |
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129 | ;-------------------------------------------------------------------- |
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130 | ALIGN JUMP_ALIGN |
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131 | DisplayContext_PrepareOffScreenBufferInESBXwithLengthInCX: |
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132 | push ds |
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133 | |
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134 | LOAD_BDA_SEGMENT_TO ds, di |
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135 | xchg ax, bx |
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136 | mov bx, es |
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137 | call DisplayContext_SetCharacterPointerFromBXAX ; ES:DI now has the pointer |
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138 | |
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139 | mov bl, ATTRIBUTES_NOT_USED |
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140 | mov ax, BUFFER_OUTPUT_WITH_CHAR_ONLY |
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141 | call DisplayContext_SetCharOutputFunctionFromAXwithAttribFlagInBL |
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142 | mov [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.wCharOutParam], cx |
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143 | |
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144 | mov bx, di |
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145 | pop ds |
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146 | ret |
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147 | |
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148 | |
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149 | ;-------------------------------------------------------------------- |
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150 | ; DisplayContext_SynchronizeToHardware |
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151 | ; Parameters: |
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152 | ; DS: BDA segment (zero) |
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153 | ; Returns: |
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154 | ; Nothing |
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155 | ; Corrupts registers: |
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156 | ; AX, DX |
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157 | ;-------------------------------------------------------------------- |
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158 | ALIGN JUMP_ALIGN |
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159 | DisplayContext_SynchronizeToHardware: |
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160 | call DisplayPage_SynchronizeToHardware |
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161 | call DisplayCursor_SynchronizeShapeToHardware |
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162 | jmp DisplayCursor_SynchronizeCoordinatesToHardware |
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163 | |
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164 | |
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165 | ;-------------------------------------------------------------------- |
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166 | ; DisplayContext_SetCharacterPointerFromBXAX |
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167 | ; Parameters: |
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168 | ; BX:AX: Ptr to destination for next character to output |
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169 | ; DS: BDA segment (zero) |
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170 | ; Returns: |
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171 | ; ES:DI: Pointer that was in BX:AX |
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172 | ; Corrupts registers: |
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173 | ; AX |
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174 | ;-------------------------------------------------------------------- |
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175 | ALIGN JUMP_ALIGN |
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176 | DisplayContext_SetCharacterPointerFromBXAX: |
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177 | mov [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.fpCursorPosition], ax |
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178 | mov [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.fpCursorPosition+2], bx |
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179 | xchg di, ax |
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180 | mov es, bx |
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181 | ret |
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182 | |
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183 | |
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184 | ;-------------------------------------------------------------------- |
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185 | ; DisplayContext_GetCharacterPointerToBXAX |
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186 | ; Parameters: |
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187 | ; DS: BDA segment (zero) |
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188 | ; Returns: |
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189 | ; BX:AX: Ptr to destination for next character to output |
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190 | ; Corrupts registers: |
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191 | ; Nothing |
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192 | ;-------------------------------------------------------------------- |
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193 | ALIGN JUMP_ALIGN |
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194 | DisplayContext_GetCharacterPointerToBXAX: |
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195 | mov ax, [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.fpCursorPosition] |
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196 | mov bx, [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.fpCursorPosition+2] |
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197 | ret |
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198 | |
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199 | |
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200 | ;-------------------------------------------------------------------- |
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201 | ; DisplayContext_SetCharOutputFunctionFromAXwithAttribFlagInBL |
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202 | ; Parameters: |
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203 | ; AX: Offset to character output function |
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204 | ; BL: Attribute Flag |
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205 | ; DS: BDA segment (zero) |
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206 | ; Returns: |
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207 | ; Nothing |
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208 | ; Corrupts registers: |
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209 | ; BL |
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210 | ;-------------------------------------------------------------------- |
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211 | ALIGN JUMP_ALIGN |
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212 | DisplayContext_SetCharOutputFunctionFromAXwithAttribFlagInBL: |
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213 | and bl, FLG_CONTEXT_ATTRIBUTES |
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214 | and BYTE [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.bFlags], ~FLG_CONTEXT_ATTRIBUTES |
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215 | or [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.bFlags], bl |
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216 | mov [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.fnCharOut], ax |
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217 | ret |
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218 | |
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219 | |
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220 | ;-------------------------------------------------------------------- |
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221 | ; DisplayContext_SetCharacterAttributeFromAL |
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222 | ; Parameters: |
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223 | ; AL: Character attribute |
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224 | ; DS: BDA segment (zero) |
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225 | ; Returns: |
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226 | ; Nothing |
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227 | ; Corrupts registers: |
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228 | ; Nothing |
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229 | ;-------------------------------------------------------------------- |
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230 | ALIGN JUMP_ALIGN |
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231 | DisplayContext_SetCharacterAttributeFromAL: |
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232 | mov [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.bAttribute], al |
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233 | ret |
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234 | |
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235 | |
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236 | ;-------------------------------------------------------------------- |
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237 | ; DisplayContext_SetCharacterOutputParameterFromAX |
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238 | ; Parameters: |
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239 | ; AX: Parameter for Character Output function |
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240 | ; DS: BDA segment (zero) |
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241 | ; Returns: |
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242 | ; Nothing |
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243 | ; Corrupts registers: |
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244 | ; Nothing |
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245 | ;-------------------------------------------------------------------- |
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246 | ALIGN JUMP_ALIGN |
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247 | DisplayContext_SetCharacterOutputParameterFromAX: |
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248 | mov [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.wCharOutParam], ax |
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249 | ret |
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250 | |
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251 | ;-------------------------------------------------------------------- |
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252 | ; DisplayContext_GetCharacterOutputParameterToDX |
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253 | ; Parameters: |
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254 | ; DS: BDA segment (zero) |
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255 | ; Returns: |
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256 | ; DX: User parameter for Character Output function |
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257 | ; Corrupts registers: |
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258 | ; Nothing |
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259 | ;-------------------------------------------------------------------- |
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260 | ALIGN JUMP_ALIGN |
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261 | DisplayContext_GetCharacterOutputParameterToDX: |
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262 | mov dx, [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.wCharOutParam] |
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263 | ret |
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264 | |
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265 | |
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266 | ;-------------------------------------------------------------------- |
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267 | ; DisplayContext_GetCharacterOffsetToAXfromByteOffsetInAX |
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268 | ; Parameters: |
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269 | ; AX: Offset in bytes from some character to another |
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270 | ; DS: BDA segment (zero) |
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271 | ; Returns: |
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272 | ; AX: Offset in characters from some character to another |
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273 | ; Corrupts registers: |
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274 | ; Nothing |
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275 | ;-------------------------------------------------------------------- |
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276 | ALIGN JUMP_ALIGN |
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277 | DisplayContext_GetCharacterOffsetToAXfromByteOffsetInAX: |
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278 | test BYTE [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.bFlags], FLG_CONTEXT_ATTRIBUTES |
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279 | jz SHORT ReturnOffsetInAX |
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280 | sar ax, 1 ; BYTE count to WORD count |
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281 | ret |
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282 | |
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283 | ;-------------------------------------------------------------------- |
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284 | ; DisplayContext_GetByteOffsetToAXfromCharacterOffsetInAX |
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285 | ; Parameters: |
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286 | ; AX: Offset in characters from some character to another |
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287 | ; DS: BDA segment (zero) |
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288 | ; Returns: |
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289 | ; AX: Offset in bytes from some character to another |
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290 | ; Corrupts registers: |
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291 | ; Nothing |
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292 | ;-------------------------------------------------------------------- |
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293 | ALIGN JUMP_ALIGN |
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294 | DisplayContext_GetByteOffsetToAXfromCharacterOffsetInAX: |
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295 | test BYTE [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.bFlags], FLG_CONTEXT_ATTRIBUTES |
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296 | jz SHORT ReturnOffsetInAX |
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297 | sal ax, 1 ; WORD count to BYTE count |
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298 | ALIGN JUMP_ALIGN, ret |
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299 | ReturnOffsetInAX: |
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300 | ret |
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