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Routines |
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Used by the routine at Handler_DisplayRoomImage.
Handles displaying the exits available for the current room.
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| Handler_RoomExits | AC02 | CALL ClearScreen | Call ClearScreen. | |
| AC05 | LD A,$18 | Set up the printing position. | ||
| AC07 | CALL Print_RoomDescription | |||
| AC0A | CALL GetRoomPointer | Call GetRoomPointer which loads HL with the room data pointer. | ||
| AC0D | LD D,H | Store this in DE for later. | ||
| AC0E | LD E,L | |||
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Count the number of exits in the room data.
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| AC0F | LD B,$06 | Set an "exits" counter in B of 06. | ||
| AC11 | LD C,$00 | Initialise C to 00 to count the number of valid exits. | ||
| AC13 | XOR A | Set A to 00 which is used just for the comparison. | ||
| RoomExitsCount_Loop | AC14 | CP (HL) | Does this room have an exit? | |
| AC15 | JR Z,RoomExitsCount_Skip | Jump to RoomExitsCount_Skip if this room doesn't have an exit for this position. | ||
| AC17 | INC C | Increment the valid exits count by one. | ||
| RoomExitsCount_Skip | AC18 | INC HL | Move to the next byte of room data. | |
| AC19 | DJNZ RoomExitsCount_Loop | Decrease the exits counter by one and loop back to RoomExitsCount_Loop until all the exits have been checked. | ||
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Process the exits count result.
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| AC1B | OR C | Jump to RoomExits_YouCanSee if no exits were found. | ||
| AC1C | JR Z,RoomExits_YouCanSee | |||
| AC1E | LD A,C | Jump to RoomMultipleExits if more than 01 exit was found. | ||
| AC1F | CP $01 | |||
| AC21 | JR NZ,RoomMultipleExits | |||
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Only one exit was found:
Print "
There is an exit ".
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| AC23 | LD HL,$A8AA | HL=Messaging_ThereIsAnExit. | ||
| AC26 | CALL PrintString | Call PrintString. | ||
| AC29 | LD H,D | Retrieve the room data pointer and load it into HL. | ||
| AC2A | LD L,E | |||
| AC2B | LD IX,$AAE2 | Set a pointer in IX to Table_Directions. | ||
| AC2F | XOR A | Set A to 00 which is used just for the comparison. | ||
| AC30 | JR RoomCheckForExit | Jump to RoomCheckForExit. | ||
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Move both the pointers to the next item of data (increment by two for the direction name table pointer as it contains addresses).
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| RoomCheckForExit_Loop | AC32 | INC HL | Move to the next byte of room data. | |
| AC33 | INC IX | Increment the direction name table pointer by two. | ||
| AC35 | INC IX | |||
| RoomCheckForExit | AC37 | CP (HL) | Jump to RoomCheckForExit_Loop if the current exit isn't a valid exit. | |
| AC38 | JR Z,RoomCheckForExit_Loop | |||
| AC3A | LD L,(IX+$00) | Get the direction name from the direction name table. | ||
| AC3D | LD H,(IX+$01) | |||
| AC40 | CALL PrintString | Call PrintString to print the direction name. | ||
| AC43 | JR RoomExits_PrintFullStop | Jump to RoomExits_PrintFullStop. | ||
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More than one exit was found:
Print "
There are exits:-".
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| RoomMultipleExits | AC45 | LD HL,$A897 | HL=Messaging_ThereAreExits. | |
| AC48 | CALL PrintStringAndNewline | Call PrintStringAndNewline. | ||
| AC4B | LD H,D | Retrieve the room data pointer and load it into HL. | ||
| AC4C | LD L,E | |||
| AC4D | LD IX,$AAE2 | Set a pointer in IX to Table_Directions. | ||
| AC51 | XOR A | Set A to 00 which is used just for the comparison. | ||
| AC52 | JR RoomCheckForExits | Jump to RoomCheckForExits. | ||
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So as not to corrupt the pointer to the room data (as HL is also used when printing), it's temporarily held in DE.
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| RoomExits_Initialise | AC54 | EX DE,HL | Switch back the DE and HL registers. | |
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Move both the pointers to the next item of data (increment by two for the direction name table pointer as it contains addresses).
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| RoomCheckForExits_Loop | AC55 | INC HL | Move to the next byte of room data. | |
| AC56 | INC IX | Increment the direction name table pointer by two. | ||
| AC58 | INC IX | |||
| RoomCheckForExits | AC5A | CP (HL) | Jump to RoomCheckForExits_Loop if the current exit isn't a valid exit. | |
| AC5B | JR Z,RoomCheckForExits_Loop | |||
| AC5D | EX DE,HL | Temporarily store the room data pointer in DE. | ||
| AC5E | LD L,(IX+$00) | Get the direction name from the direction name table. | ||
| AC61 | LD H,(IX+$01) | |||
| AC64 | CALL PrintString | Call PrintString to print the direction name. | ||
| AC67 | DEC C | Decrease the valid exits count by one. | ||
| AC68 | LD A,C | Jump to RoomExits_PrintFullStop if there are no more exits to process. | ||
| AC69 | CP $01 | |||
| AC6B | JR C,RoomExits_PrintFullStop | |||
| AC6D | JR Z,RoomExits_PrintAmpersand | Jump to RoomExits_PrintAmpersand if there is only one exit left to process. | ||
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Print a comma character: "
,".
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| AC6F | LD A,$2C | A=2C. | ||
| AC71 | CALL PrintCharacter | Call PrintCharacter. | ||
| AC74 | XOR A | Reset A back to 00 for the comparison. | ||
| AC75 | JR RoomExits_Initialise | Jump back to RoomExits_Initialise to continue processing. | ||
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Print " & ".
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| RoomExits_PrintAmpersand | AC77 | LD HL,$A893 | HL=Messaging_Ampersand. | |
| AC7A | CALL PrintString | Call PrintString. | ||
| AC7D | XOR A | Reset A back to 00 for the comparison. | ||
| AC7E | JR RoomExits_Initialise | Jump to RoomExits_Initialise to continue processing. | ||
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Print ".".
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| RoomExits_PrintFullStop | AC80 | LD HL,$AA15 | HL=Messaging_FullStop. | |
| AC83 | CALL PrintStringAndNewline | Call PrintStringAndNewline. | ||
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Are there any objects here?
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| RoomExits_YouCanSee | AC86 | LD A,($A7C3) | A=*CurrentRoom. | |
| AC89 | CALL CheckRoomObjects | Call CheckRoomObjects. | ||
| AC8C | RET NZ | Return if no objects were found at this location. | ||
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Print "
You can see:-".
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| AC8D | LD HL,$A884 | HL=Messaging_YouCanSee. | ||
| AC90 | CALL PrintStringAndNewline | Call PrintStringAndNewline. | ||
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Print the objects at this location.
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| AC93 | LD A,($A7C3) | A=*CurrentRoom. | ||
| AC96 | CALL PrintObjects | Call PrintObjects. | ||
| AC99 | RET | Return. | ||
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