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Routines |
| Prev: D672 | Up: Map | Next: D700 |
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Used by the routine at LocatePicture.
Adjusts the number of rows of a piece that is near the top of the screen so that it does not go above the top, and, for a sloped piece, limits the number of steps left in the segment to two. The screen address is loaded from SegmentScreenAddress.
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| AdjustPiece | D6DB | LD B,A | B=A. | |||||
| D6DC | LD A,($CE5A) | The vertical step copy. | ||||||
| D6DF | NEG | Negate A. | ||||||
| D6E1 | ADD A,B | A gains B. | ||||||
| D6E2 | SUB $18 | Subtract 18 from A. | ||||||
| D6E4 | JP NC,AdjustPiece_Address | Jump to AdjustPiece_Address if the carry flag is clear. | ||||||
| D6E7 | CPL | Invert A. | ||||||
| D6E8 | SRL A | Shift A right. | ||||||
| D6EA | NEG | Negate A. | ||||||
| D6EC | ADD A,E | A gains E. | ||||||
| D6ED | LD E,A | E=A. | ||||||
| D6EE | LD A,($CE37) | The vertical step. | ||||||
| D6F1 | AND A | Jump to AdjustPiece_Address if A is zero. | ||||||
| D6F2 | JR Z,AdjustPiece_Address | |||||||
| D6F4 | EXX | Switch to the alternate registers. | ||||||
| D6F5 | LD A,C | A=C. | ||||||
| D6F6 | CP $01 | Jump to AdjustPiece_Columns if A is 01. | ||||||
| D6F8 | JR Z,AdjustPiece_Columns | |||||||
| D6FA | LD C,$02 | C=02. | ||||||
| AdjustPiece_Columns | D6FC | EXX | Switch to the alternate registers. | |||||
| AdjustPiece_Address | D6FD | LD HL,($CE49) | Fetch the word at SegmentScreenAddress into HL. | |||||
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Continue on to JumpToDrawingRoutine.
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| Prev: D672 | Up: Map | Next: D700 |