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Routines |
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Used by the routine at DrawingSetup.
Moves the screen address up one character row.
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| Drawing_StepUpOneRow | 80F5 | PUSH AF | One screen row is 20 bytes. | |
| 80F6 | PUSH DE | |||
| 80F7 | LD DE,$0020 | |||
| 80FA | AND A | Clear carry before stepping the screen address back one row. | ||
| 80FB | SBC HL,DE | See how far the pointer is past 0020. | ||
| 80FD | LD A,H | Jump to Drawing_StepUpOneRow_RestoreTheRowStep if the screen address is not in row 57. | ||
| 80FE | CP $57 | |||
| 8100 | JR NZ,Drawing_StepUpOneRow_RestoreTheRowStep | |||
| 8102 | ADD HL,DE | Step down one attribute row. | ||
| Drawing_StepUpOneRow_RestoreTheRowStep | 8103 | POP DE | Restore DE and AF from the stack. | |
| 8104 | POP AF | |||
| 8105 | RET | Return. | ||
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View the equivalent code in;
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