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Routines |
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Used by the routine at GameLoop.
Advance turn-based events, then any scenic events, before the player types again.
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First process the turn-based events (if any are active).
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| ProcessGameEvents | 45939 | LD A,(44680) | Load the turn-based event flags into A. | |
| 45942 | OR A | Jump to GameScenicEventsProcessor if no turn-based events are currently active. | ||
| 45943 | JR Z,GameScenicEventsProcessor | |||
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One of the events has triggered, find which one.
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| 45945 | LD C,A | Copy the turn-based event flags into C. | ||
| 45946 | LD B,8 | Set a counter in B for the number of possible turn-based events (8). | ||
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Keep shifting the event flags one-by-one to find which bits are set.
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| GameEventChecker_Loop | 45948 | SRL C | Test the next turn-based event flag. | |
| 45950 | JR NC,GameEventChecker_Next | Jump to GameEventChecker_Next if this event bit isn't set. | ||
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The currently processed turn-based event is active, so process it.
This is: the turn-based event counters+(8-the current event counter).
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| 45952 | LD DE,0 | Calculate the turn-based event index and store it in HL. | ||
| 45955 | LD HL,44681 | |||
| 45958 | LD A,8 | |||
| 45960 | SUB B | |||
| 45961 | LD E,A | |||
| 45962 | ADD HL,DE | |||
| 45963 | DEC (HL) | Decrease the turn-based event counter at *HL by one. | ||
| 45964 | JR NZ,GameEventChecker_Next | Jump to GameEventChecker_Next if the event turn counter at *HL was still more than zero. | ||
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The event turn counter is zero, so activate the event itself.
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| 45966 | LD IX,(44754) | Load the turn-based handler pointer into IX. | ||
| 45970 | SLA E | Double the index as this table contains addresses. | ||
| 45972 | ADD IX,DE | Add this offset to IX to point to the current handler. | ||
| 45974 | LD L,(IX+0) | Get the handler address and store it in HL. | ||
| 45977 | LD H,(IX+1) | |||
| 45980 | PUSH BC | Keep the bit index and event flag byte on the stack. | ||
| 45981 | LD DE,45986 | Push GameEventChecker_Return onto the stack so that the next return will go on to continue processing events. | ||
| 45984 | PUSH DE | |||
| 45985 | JP (HL) | Jump to the routine pointed to by *HL to action the current event. | ||
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Once the event handler has run, this is where the routine will resume.
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| GameEventChecker_Return | 45986 | POP BC | Restore the event bit index counter and event flag byte from the stack. | |
| GameEventChecker_Next | 45987 | DJNZ GameEventChecker_Loop | Decrease the event bit counter by one and loop back to GameEventChecker_Loop until all the event status bits have been processed. | |
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Process scenic events.
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| GameScenicEventsProcessor | 45989 | NOP | A spare NOP, probably where an instruction was patched out, before the scenic events are processed. |
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| 45990 | LD HL,(44780) | Point HL at the scenic-event list. | ||
| 45993 | LD A,(44792) | Read the scenic-event count into A. | ||
| 45996 | OR A | Leave scenic events alone when none are defined. | ||
| 45997 | JR Z,ProcessGameEvents_4 | |||
| 45999 | LD B,A | Count the scenic events and read the first one. | ||
| 46000 | JR ProcessGameEvents_0 | |||
| ScenicEvent_Loop | 46002 | INC HL | Read this scenic event's item. | |
| ProcessGameEvents_0 | 46003 | LD A,(HL) | ||
| 46004 | PUSH HL | Remember which scenic event this is. | ||
| 46005 | CALL GetItemRoom | Call GetItemRoom to read which room holds the item. | ||
| 46008 | POP HL | Restore the pointer to this scenic event from the stack. | ||
| 46009 | AND A | Skip a scenic event that is not in play. | ||
| 46010 | JR Z,ProcessGameEvents_3 | |||
| 46012 | LD C,A | Remember which room holds this scenic item. | ||
| 46013 | LD A,(44749) | Read the current room into A. | ||
| 46016 | CP C | Skip a scenic event that is already in this room. | ||
| 46017 | JR Z,ProcessGameEvents_3 | |||
| 46019 | PUSH BC | Remember this scenic event while its next room is chosen. | ||
| 46020 | PUSH HL | |||
| 46021 | LD A,(44792) | Read the scenic-event count into A. | ||
| 46024 | SUB B | Turn the remaining count into this event's index. | ||
| 46025 | LD E,A | |||
| 46026 | LD IX,(44782) | Point IX at this event's room list. | ||
| 46030 | CALL GetTableEntry | Call GetTableEntry to look up the table entry. | ||
| 46033 | CALL FetchFrames | Call FetchFrames to read the frame counter. | ||
| 46036 | LD B,A | Use the frame counter as a step through the room list. | ||
| 46037 | LD A,255 | Use 255 as the end of the room list. | ||
| ProcessGameEvents_1 | 46039 | LD L,(IX+0) | Point at this event's room list. | |
| 46042 | LD H,(IX+1) | |||
| 46045 | JR ProcessGameEvents_2 | Start at the first room in the list. | ||
| ScenicEvent_PickRoom | 46047 | INC HL | Step to the next room in the list. | |
| ProcessGameEvents_2 | 46048 | CP (HL) | Stop at the end of the room list. | |
| 46049 | JR Z,ProcessGameEvents_1 | Wrap to the start of the list at the terminator. | ||
| 46051 | DJNZ ScenicEvent_PickRoom | Take another step while the frame count remains. | ||
| 46053 | LD C,(HL) | Take the room chosen for this scenic item. | ||
| 46054 | POP HL | Restore the pointer to this scenic event from the stack. | ||
| 46055 | LD B,(HL) | Take this scenic event's item. | ||
| 46056 | PUSH HL | Remember the scenic event while its item is moved. | ||
| 46057 | CALL SetItemRoom | Call SetItemRoom to store the item's room. | ||
| 46060 | POP HL | Restore HL, BC from the stack. | ||
| 46061 | POP BC | |||
| ProcessGameEvents_3 | 46062 | DJNZ ScenicEvent_Loop | Step down B by one and jump to ScenicEvent_Loop until it is zero. | |
| ProcessGameEvents_4 | 46064 | RET | Return. | |
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View the equivalent code in;
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