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Routines |
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Used by the routines at UnlinkNextDisplayRecord and ProcessDisplayEntry.
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| SelectJumpIfNotZero | B633 | LD A,$20 | Use the JR NZ opcode (20). |
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This entry point is used by the routine at SelectJumpIfZero.
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| SelectJumpIfNotZero_WriteOpcode | B635 | LD ($B649),A | Write the opcode into the jumps at B649 and B658. | |
| B638 | LD ($B658),A | |||
| B63B | LD IX,($B18E) | Read the pointer at B18C+02. | ||
| B63F | LD L,(IX+$04) | Read the handler address from bytes 04-05 of the record. | ||
| B642 | LD H,(IX+$05) | |||
| B645 | BIT 7,(IX+$07) | Jump to SelectJumpIfNotZero_LocationActionFlags if a marker on the character record is set. The opcode at B649 is modified by SelectJumpIfNotZero_WriteOpcode. | ||
| B649 | JR NZ,SelectJumpIfNotZero_LocationActionFlags | |||
| B64B | LD HL,$0000 | Clear the pointer. | ||
| SelectJumpIfNotZero_LocationActionFlags | B64E | EX (SP),HL | Swap HL with the return address. | |
| B64F | PUSH HL | Save that address, and read the location and the action flags. | ||
| B650 | LD L,(IX+$02) | |||
| B653 | LD H,(IX+$03) | |||
| B656 | BIT 5,H | Jump ahead to SelectJumpIfNotZero_ReturnWithPointers if bit 5 is present. The opcode at B658 is modified by SelectJumpIfNotZero_WriteOpcode. | ||
| B658 | JR NZ,SelectJumpIfNotZero_ReturnWithPointers | |||
| B65A | LD HL,$0000 | Clear the pointer. | ||
| SelectJumpIfNotZero_ReturnWithPointers | B65D | EX (SP),HL | Leave the location pointer (or 0000 when bit 5 is clear) on the stack in place of the address saved there. | |
| B65E | JP (HL) | Return to the caller (its address is now in HL), leaving the location pointer and the handler address on the stack. | ||
| B65F | LD A,($A00F) | Jump to SelectJumpIfNotZero_MessagePrintMessage if the display mode is 05. | ||
| B662 | CP $05 | |||
| B664 | JR Z,SelectJumpIfNotZero_MessagePrintMessage | |||
| B666 | CP $06 | Jump to SelectJumpIfNotZero_MessagePrintMessage when the display mode is 06. | ||
| B668 | JR Z,SelectJumpIfNotZero_MessagePrintMessage | |||
| B66A | LD A,($B173) | Jump ahead to SelectJumpIfNotZero_TestDisplayFlag if bit 7 of display mode flag at DisplayModeFlag is clear. | ||
| B66D | BIT 7,A | |||
| B66F | JR Z,SelectJumpIfNotZero_TestDisplayFlag | |||
| SelectJumpIfNotZero_MessagePrintMessage | B671 | LD HL,$6855 | Take the message, then call PrintTextAndHandleControlCharacters to print the message. | |
| B674 | CALL PrintTextAndHandleControlCharacters | |||
| B677 | RET | Return. | ||
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Test the display flag, and use the display data pointer when that flag is set.
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| SelectJumpIfNotZero_TestDisplayFlag | B678 | LD HL,$B16D | Test bit 0 of the display flag and point HL at the display data pointer. | |
| B67B | BIT 0,(HL) | |||
| B67D | LD HL,$B172 | |||
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Build this display entry when the flag is clear.
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| B680 | CALL NZ,ProcessDisplayEntry | Call ProcessDisplayEntry if bit 0 of this byte is set. | ||
| B683 | CALL SelectJumpIfNotZero | Call SelectJumpIfNotZero to plant the JR NZ opcode and test the character record. |
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| B686 | LD A,($B16D) | Read the display flag and take the display data pointer. | ||
| B689 | LD HL,$B172 | |||
| SelectJumpIfNotZero_BitDisplayFlag | B68C | LD DE,($B186) | Jump ahead to SelectJumpIfNotZero_ClearStackedPointers if bit 0 of display flag at DisplayFlag is clear. | |
| B690 | PUSH DE | |||
| B691 | BIT 0,A | |||
| B693 | JR Z,SelectJumpIfNotZero_ClearStackedPointers | |||
| B695 | CALL RestoreSavedCharacterRecord | Call RestoreSavedCharacterRecord to restore the saved character record, then jump to SelectJumpIfNotZero_MessagePrintMessageAgain with the message at 05B3. | ||
| B698 | LD HL,$05B3 | |||
| B69B | JR SelectJumpIfNotZero_MessagePrintMessageAgain | |||
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Clear the stacked pointers, then print the message at 05DB.
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| SelectJumpIfNotZero_ClearStackedPointers | B69D | LD HL,$0000 | Push three zero words for the message. | |
| B6A0 | PUSH HL | |||
| B6A1 | PUSH HL | |||
| B6A2 | PUSH HL | |||
| B6A3 | LD HL,$05DB | Take the message at 05DB. | ||
| SelectJumpIfNotZero_MessagePrintMessageAgain | B6A6 | PUSH HL | Take the message, then call PrintTextAndHandleControlCharacters to print the message. | |
| B6A7 | LD HL,$6894 | |||
| B6AA | CALL PrintTextAndHandleControlCharacters | |||
| B6AD | RET | Return. | ||
| B6AE | LD A,($A010) | Jump to SelectJumpIfNotZero_MessagePrintMessage if the display mode is 05. | ||
| B6B1 | CP $05 | |||
| B6B3 | JR Z,SelectJumpIfNotZero_MessagePrintMessage | |||
| B6B5 | CP $06 | Jump to SelectJumpIfNotZero_MessagePrintMessage when the display mode is 06. | ||
| B6B7 | JR Z,SelectJumpIfNotZero_MessagePrintMessage | |||
| B6B9 | LD A,($B179) | Jump back to SelectJumpIfNotZero_MessagePrintMessage while bit 7 of display mode flag (B179) is present. | ||
| B6BC | BIT 7,A | |||
| B6BE | JR NZ,SelectJumpIfNotZero_MessagePrintMessage | |||
| B6C0 | LD HL,$B16E | Take the display flag and take the display mode flag. | ||
| B6C3 | BIT 0,(HL) | |||
| B6C5 | LD HL,$B178 | |||
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Build the alternate display entry.
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| B6C8 | CALL NZ,ProcessDisplayEntryAlternate | Call ProcessDisplayEntryAlternate if bit 0 of this byte is set. | ||
| B6CB | CALL SelectJumpIfZero | Call SelectJumpIfZero to plant the JR Z opcode. |
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| B6CE | LD A,($B16E) | Jump back to SelectJumpIfNotZero_BitDisplayFlag to check flag and set display parameter. | ||
| B6D1 | LD HL,$B178 | |||
| B6D4 | JR SelectJumpIfNotZero_BitDisplayFlag | |||
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View the equivalent code in;
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