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Routines |
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The handler of DrawGraphic for a graphic that is mirrored from left to right. Each row is read from its end and the bits of each byte are reversed with ReverseBits.
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| DrawGraphic_Mirrored | 99E5 | POP BC | Restore the attribute and graphic ID from the stack. | |
| 99E6 | CALL GetBlendInstruction | Call GetBlendInstruction to get the instruction to mix the graphic with the screen. | ||
| 99E9 | LD ($99F9),A | Write it over the instruction at 99F9. | ||
| 99EC | CALL GetGraphicDetails | Call GetGraphicDetails to get the details of the graphic. | ||
| DrawGraphic_Mirrored_Row | 99EF | PUSH BC | Stash the width and height on the stack. | |
| 99F0 | PUSH HL | Stash the screen address on the stack. | ||
| 99F1 | CALL AddWidthToAddress | Call AddWidthToAddress to move DE on to the end of the row. | ||
| DrawGraphic_Mirrored_Byte | 99F4 | DEC DE | Move DE back one byte. | |
| 99F5 | LD A,(DE) | Fetch the byte of the graphic. | ||
| 99F6 | CALL ReverseBits | Call ReverseBits to reverse the bits. | ||
| 99F9 | NOP | This is replaced by an instruction that mixes A with the screen. | ||
| 99FA | LD (HL),A | Write A to the screen. | ||
| 99FB | INC L | Move HL on to the next byte. | ||
| 99FC | DJNZ DrawGraphic_Mirrored_Byte | Decrease the width by one and loop back to DrawGraphic_Mirrored_Byte until all of the bytes in the row have been drawn. | ||
| 99FE | POP HL | Restore the screen address from the stack. | ||
| 99FF | CALL ScreenPosition1PixelAbove | Call ScreenPosition1PixelAbove to move up a line. | ||
| 9A02 | POP BC | Restore the width and height from the stack. | ||
| 9A03 | CALL AddWidthToAddress | Call AddWidthToAddress to move DE on to the start of the next row. | ||
| 9A06 | DEC C | Decrease the height by one and loop back to DrawGraphic_Mirrored_Row until all of the rows have been done. | ||
| 9A07 | JR NZ,DrawGraphic_Mirrored_Row | |||
| 9A09 | RET | Return. | ||
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