Sherlock: Routine at 51647

Used by the routine at ProcessObjectDisplayEntry.

HL points at a display record (flags, value, optional handler word, optional five extra bytes). Checks the record against the current object, character and graphics, runs its handler if bit 6 is set, and then either returns the address after the record (bit 7 set) or runs the code that follows it via 51812. A non-zero return means the script step succeeded.

Used by the routine at ProcessObjectDisplayEntry. HL points at a display record (flags, value, optional handler word, optional five extra bytes). Checks the record against the current object, character and graphics, runs its handler if bit 6 is set, and then either returns the address after the record (bit 7 set) or runs the code that follows it via 51812. A non-zero return means the script step succeeded.
ProcessDisplayRecord	51647	PUSH HL	Point IY at the display record and call CheckObjectVisibility to check whether the object is visible.
	51648	POP IY
	51650	CALL CheckObjectVisibility
	51653	JR NC,ProcessDisplayRecord_TestHandler	Go to ProcessDisplayRecord_TestHandler if CheckObjectVisibility finds the object is not visible.
Bit 5 of the record flags is clear?
	51655	LD A,(IY+0)	Jump to ProcessDisplayRecord_TestHandler if bit 5 of the record flags is clear.
	51658	AND 32
	51660	JR Z,ProcessDisplayRecord_TestHandler
	51662	LD HL,52155	Point HL at the failure step at 52155.
ProcessDisplayRecord_Fail	51665	XOR A	Clear A.
	51666	RET	Return.
Test the character field, the graphics field and the handler bit.
ProcessDisplayRecord_TestHandler	51667	CALL TestLowBitsOfCharacter	Go to ProcessDisplayRecord_Fail if the character test on this record fails.
	51670	JR Z,ProcessDisplayRecord_Fail
	51672	CALL TestLowBitsOfGraphics	Go to ProcessDisplayRecord_Fail if the graphics test on this record fails.
	51675	JR Z,ProcessDisplayRecord_Fail
	51677	BIT 6,(IY+0)	Skip ahead to ProcessDisplayRecord_TestParser unless bit 6 of the record flags is set.
	51681	JR Z,ProcessDisplayRecord_TestParser
	51683	LD L,(IY+2)	Read the handler word at bytes 2/3 of the record and save IY.
	51686	LD H,(IY+3)
	51689	PUSH IY
	51691	CALL 52020	Run the handler via 52020.
	51694	POP IY	Restore IY from the stack.
	51696	JR Z,ProcessDisplayRecord_Fail	Go to ProcessDisplayRecord_Fail if the handler returns zero.
ProcessDisplayRecord_TestParser	51698	LD A,(40971)	Jump to ProcessDisplayRecord_StoreCount if the parser flag at 40971 is set.
	51701	AND A
	51702	JR NZ,ProcessDisplayRecord_StoreCount
	51704	OR %00000001	Reset the zero flag.
	51706	RET	Return.
Take the high nibble of the record's value byte (1) as the count and store it at CharacterScriptCycles.
ProcessDisplayRecord_StoreCount	51707	PUSH IY	Save the record pointer and read the value byte (1).
	51709	LD A,(IY+1)	Save the record pointer and read the value byte (1).
	51712	RRCA	Shift that byte down by four bits.
	51713	RRCA
	51714	RRCA
	51715	RRCA
	51716	AND 15	Keep the high nibble.
	51718	LD L,A	Use that nibble as the low byte of the count.
	51719	LD H,0	Clear the high byte.
	51721	LD (40991),HL	Store the count at CharacterScriptCycles.
ProcessDisplayRecord_ComputeLength	51724	POP HL	Restore the record address from the stack.
	51725	LD DE,2	Step over the two-byte header.
	51728	ADD HL,DE	Step over the two-byte header.
	51729	BIT 6,(IY+0)	Skip ahead to ProcessDisplayRecord_TestFiveExtraBytes unless bit 6 of the record flags is set.
	51733	JR Z,ProcessDisplayRecord_TestFiveExtraBytes
	51735	ADD HL,DE	Step over the handler word.
ProcessDisplayRecord_TestFiveExtraBytes	51736	LD DE,5	Skip ahead to ProcessDisplayRecord_SaveAttributes unless bit 4 of the record flags is set.
	51739	BIT 4,(IY+0)
	51743	JR Z,ProcessDisplayRecord_SaveAttributes
	51745	ADD HL,DE	Step over the five extra bytes.
ProcessDisplayRecord_SaveAttributes	51746	LD A,(40970)	Read the character attribute and store it in the workspace byte at 50321.
	51749	LD (50321),A
	51752	LD IX,(40979)	Point IX at the current object.
	51756	LD A,(IX+15)	Read the object's attribute and store it in the workspace byte at 50322, then save the address after the record.
	51759	LD (50322),A
	51762	PUSH HL
	51763	PUSH IY	Save the record, store 1 in the parser flag at 40972, and call ReadSavedCharacter.
	51765	LD A,1
	51767	LD (40972),A
	51770	CALL ReadSavedCharacter
	51773	POP IY	Restore the pointers from the stack.
	51775	POP HL	Restore the pointers from the stack.
	51776	BIT 7,(IY+0)	And skip ahead to ProcessDisplayRecord_FillLocationLow unless bit 7 of the record flags is set.
	51780	JR Z,ProcessDisplayRecord_FillLocationLow
	51782	SCF	Set the carry.
	51783	RET	Return with HL pointing past the record, so the script resumes there.
Fill a location byte that is still 255 from the room parameters.
ProcessDisplayRecord_FillLocationLow	51784	LD A,(40919)	Go to ProcessDisplayRecord_FillLocationHigh unless the low byte of LocationValue is 255.
	51787	INC A
	51788	JR NZ,ProcessDisplayRecord_FillLocationHigh
	51790	LD A,(41012)	Copy the room display parameter into LocationValue.
	51793	LD (40919),A	Copy the room display parameter into LocationValue.
ProcessDisplayRecord_FillLocationHigh	51796	LD A,(40920)	Go to ProcessDisplayRecord_RunFollowingCode unless the high byte of LocationValue is 255.
	51799	INC A
	51800	JR NZ,ProcessDisplayRecord_RunFollowingCode
	51802	LD A,(41013)	Copy the room graphics parameter into the high byte of LocationValue.
	51805	LD (40920),A
ProcessDisplayRecord_RunFollowingCode	51808	XOR A	Clear the flag at 51886 and run the code that follows the record (at HL) via RunDisplayRecordCode.
	51809	LD (51886),A
	51812	CALL RunDisplayRecordCode
	51815	PUSH AF	Call ReadCharacterTimetable, saving result and the pointer.
	51816	PUSH HL
	51817	CALL ReadCharacterTimetable
	51820	LD A,(51886)	Call CheckCharacterDisguise if the room flag at 51886 is clear.
	51823	AND A
	51824	CALL Z,CheckCharacterDisguise
	51827	POP HL	Restore the pointer from the stack.
	51828	POP AF	Restore AF from the stack.
	51829	RET	Return.