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Routines |
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Used by the routines at PrintHandler_Ink, PrintHandler_Paper, PrintHandler_Flash, PrintHandler_Bright, PrintHandler_LeftMargin and PrintHandler_SelectFont.
Parameter mask and validation utility. Called by control code parameter handlers before processing their byte. Resets PrintState_Handler to the default handler (PrintHandler), then masks A to the valid range defined by B (which must be a power of two). If the parameter is out of range, sets a flag in 8007.
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| PrintHandler_MaskParam | 8EE6 | LD HL,$8DE3 | Reset PrintState_Handler to PrintHandler (default handler). | |
| 8EE9 | LD ($800A),HL | |||
| 8EEC | CP B | Test whether the parameter (A) is within the valid range (B). | ||
| 8EED | JR C,PrintHandler_MaskParam_Mask | If the parameter is within range, jump to PrintHandler_MaskParam_Mask. | ||
| 8EEF | SET 0,(IX+$07) | Otherwise set the out-of-range flag (bit 0 of *8007). | ||
| PrintHandler_MaskParam_Mask | 8EF3 | DEC B | Decrement B to form a bitmask (e.g. 08 → 07 = %00000111). | |
| 8EF4 | AND B | Mask A to the valid range. | ||
| 8EF5 | LD B,A | B=masked parameter value. | ||
| 8EF6 | RET | Return. | ||
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