Routines
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33105: Drawing: Plot The Selected Pixel
Used by the routine at DrawingSetup.
Plots one line. Bit 0 of the direction chooses which coordinate steps first, and L is how many pixels are drawn.
Drawing_PlotTheSelectedPixel 33105 BIT 0,C Jump to Drawing_PlotTheSelectedPixel_OtherDirection when bit 0 of the direction is set.
33107 JR NZ,Drawing_PlotTheSelectedPixel_OtherDirection
33109 PUSH HL
33110 PUSH BC
Drawing_PlotTheSelectedPixel_AddressThePixel 33111 CALL Drawing_AddressThePixel Call Drawing_AddressThePixel to address the pixel.
33114 BIT 2,C Jump to Drawing_PlotTheSelectedPixel_StepHigh if bit 2 of the direction is clear.
33116 JR Z,Drawing_PlotTheSelectedPixel_StepHigh
33118 CALL Drawing_RetreatTheHighCoordinate Call Drawing_RetreatTheHighCoordinate to retreat the high coordinate.
33121 JR Z,Drawing_PlotTheSelectedPixel_FinishTheFirstPass Jump to Drawing_PlotTheSelectedPixel_FinishTheFirstPass if Drawing_RetreatTheHighCoordinate wrapped the high coordinate.
33123 JR Drawing_PlotTheSelectedPixel_CountTheLength Jump to Drawing_PlotTheSelectedPixel_CountTheLength to count this pixel.
Drawing_PlotTheSelectedPixel_StepHigh 33125 CALL Drawing_AdvanceTheHighCoordinate Call Drawing_AdvanceTheHighCoordinate to advance the high coordinate.
33128 JR Z,Drawing_PlotTheSelectedPixel_FinishTheFirstPass Jump to Drawing_PlotTheSelectedPixel_FinishTheFirstPass if Drawing_AdvanceTheHighCoordinate wrapped the high coordinate.
Drawing_PlotTheSelectedPixel_CountTheLength 33130 DEC B Drop one from the remaining length.
33131 JR NZ,Drawing_PlotTheSelectedPixel_CountDownThePixels Jump to Drawing_PlotTheSelectedPixel_CountDownThePixels if it is not zero.
33133 BIT 1,C Jump to Drawing_PlotTheSelectedPixel_StepLow if bit 1 of the direction is clear.
33135 JR Z,Drawing_PlotTheSelectedPixel_StepLow
33137 CALL Drawing_RetreatTheLowCoordinate Call Drawing_RetreatTheLowCoordinate to retreat the low coordinate.
33140 JR Z,Drawing_PlotTheSelectedPixel_FinishTheFirstPass Jump to Drawing_PlotTheSelectedPixel_FinishTheFirstPass if Drawing_RetreatTheLowCoordinate wrapped the low coordinate.
33142 JR Drawing_PlotTheSelectedPixel_HoldThePixelCount Jump to Drawing_PlotTheSelectedPixel_HoldThePixelCount to bring the count back.
Drawing_PlotTheSelectedPixel_StepLow 33144 CALL Drawing_AdvanceTheLowCoordinate Call Drawing_AdvanceTheLowCoordinate to advance the low coordinate.
33147 JR Z,Drawing_PlotTheSelectedPixel_FinishTheFirstPass Jump to Drawing_PlotTheSelectedPixel_FinishTheFirstPass if Drawing_AdvanceTheLowCoordinate wrapped the low coordinate.
Drawing_PlotTheSelectedPixel_HoldThePixelCount 33149 POP BC Copy the count, leaving it on the stack.
33150 PUSH BC
Drawing_PlotTheSelectedPixel_CountDownThePixels 33151 DEC L Loop back to Drawing_PlotTheSelectedPixel_AddressThePixel until the pixel count reaches zero.
33152 JR NZ,Drawing_PlotTheSelectedPixel_AddressThePixel
Drawing_PlotTheSelectedPixel_FinishTheFirstPass 33154 POP BC Restore BC and HL from the stack.
33155 POP HL
33156 RET Return.
Drawing_PlotTheSelectedPixel_OtherDirection 33157 PUSH HL The other direction steps the low coordinate first.
33158 PUSH BC
Drawing_PlotTheSelectedPixel_StepTheLowCoordinate 33159 CALL Drawing_AddressThePixel
33162 BIT 1,C Jump to Drawing_PlotTheSelectedPixel_StepLowOtherWay if bit 1 of the direction is clear.
33164 JR Z,Drawing_PlotTheSelectedPixel_StepLowOtherWay
33166 CALL Drawing_RetreatTheLowCoordinate Call Drawing_RetreatTheLowCoordinate to retreat the low coordinate.
33169 JR Z,Drawing_PlotTheSelectedPixel_FinishTheOtherPass Jump to Drawing_PlotTheSelectedPixel_FinishTheOtherPass if Drawing_RetreatTheLowCoordinate wrapped the low coordinate.
33171 JR Drawing_PlotTheSelectedPixel_CountDownTheLength Jump to Drawing_PlotTheSelectedPixel_CountDownTheLength to skip that picture step.
Drawing_PlotTheSelectedPixel_StepLowOtherWay 33173 CALL Drawing_AdvanceTheLowCoordinate Call Drawing_AdvanceTheLowCoordinate to advance the low coordinate.
33176 JR Z,Drawing_PlotTheSelectedPixel_FinishTheOtherPass Jump to Drawing_PlotTheSelectedPixel_FinishTheOtherPass if Drawing_AdvanceTheLowCoordinate wrapped the low coordinate.
Drawing_PlotTheSelectedPixel_CountDownTheLength 33178 DEC B Drop one from the remaining length, and jump to Drawing_PlotTheSelectedPixel_RepeatForEachPixel to skip the high-coordinate step unless it is zero.
33179 JR NZ,Drawing_PlotTheSelectedPixel_RepeatForEachPixel
33181 BIT 2,C Jump to Drawing_PlotTheSelectedPixel_StepHighOtherWay if bit 2 of the direction is clear.
33183 JR Z,Drawing_PlotTheSelectedPixel_StepHighOtherWay
33185 CALL Drawing_RetreatTheHighCoordinate Call Drawing_RetreatTheHighCoordinate to retreat the high coordinate.
33188 JR Z,Drawing_PlotTheSelectedPixel_FinishTheOtherPass Jump to Drawing_PlotTheSelectedPixel_FinishTheOtherPass if Drawing_RetreatTheHighCoordinate wrapped the high coordinate.
33190 JR Drawing_PlotTheSelectedPixel_RefreshThePixelCount Jump to Drawing_PlotTheSelectedPixel_RefreshThePixelCount to bring the count back.
Drawing_PlotTheSelectedPixel_StepHighOtherWay 33192 CALL Drawing_AdvanceTheHighCoordinate Call Drawing_AdvanceTheHighCoordinate to advance the high coordinate.
33195 JR Z,Drawing_PlotTheSelectedPixel_FinishTheOtherPass Jump to Drawing_PlotTheSelectedPixel_FinishTheOtherPass if Drawing_AdvanceTheHighCoordinate wrapped the high coordinate.
Drawing_PlotTheSelectedPixel_RefreshThePixelCount 33197 POP BC Copy the count, leaving it on the stack.
33198 PUSH BC
Drawing_PlotTheSelectedPixel_RepeatForEachPixel 33199 DEC L Loop back to Drawing_PlotTheSelectedPixel_StepTheLowCoordinate until the pixel count reaches zero.
33200 JR NZ,Drawing_PlotTheSelectedPixel_StepTheLowCoordinate
Drawing_PlotTheSelectedPixel_FinishTheOtherPass 33202 POP BC Restore BC and HL from the stack.
33203 POP HL
33204 RET Return.
View the equivalent code in;
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