Sherlock: Routine at C763

C763: Read The High Byte Of The Source

Used by the routine at ReadObjectAttribute_LooksObjectFolds. Compares the high byte of the source with the bits set in the count.
ReadHighByteSource	C763	JR NZ,ReadHighByteSource_CommandOne	Jump to ReadHighByteSource_CommandOne when the folded attribute is not zero.
	C765	LD A,D	Take the byte in D.
	C766	AND C	Keep only the bits that are set in the count.
	C767	CP D	See whether the two values match.
This entry point is used by the routine at TestSeventhMarker.
ReadHighByteSource_0	C768	JP Z,TestLowBitsOfCharacter_ReportMatch	Go to TestLowBitsOfCharacter_ReportMatch if the masked attribute matches.
	C76B	JR ReadHighByteSource_FlipBitsResult	The masked attribute does not match, so go to ReadHighByteSource_FlipBitsResult to keep only the bits of D outside the mask.
For command 1, keeps the matching bits of the high byte.
ReadHighByteSource_CommandOne	C76D	CP $01	See whether the attribute is 01.
	C76F	JR NZ,ReadHighByteSource_CommandTwo	Jump to ReadHighByteSource_CommandTwo when the attribute is not one.
	C771	LD A,D	See whether any attribute bits are still set.
	C772	AND A	Clear the carry before testing the attribute mask.
	C773	JR Z,ReadHighByteSource_0	Jump to ReadHighByteSource_0 when the attribute mask is clear.
	C775	AND C	Go to ReadHighByteSource_TestWorkspaceKeepingBits if the attribute mask matches nothing.
	C776	JR Z,ReadHighByteSource_TestWorkspaceKeepingBits
	C778	JP TestLowBitsOfCharacter_ReportMatch	Jump back to TestLowBitsOfCharacter_ReportMatch to return non-zero.
For command 2, gives up when none of the selected bits are set.
ReadHighByteSource_CommandTwo	C77B	CP $02	See whether the attribute is 02.
	C77D	JR NZ,ReadHighByteSource_HighByteSource	Jump to ReadHighByteSource_HighByteSource when the attribute is not two.
	C77F	LD A,D	Go to TestLowBitsOfCharacter_ReportMatch to return zero if the attribute mask matches nothing.
	C780	AND C
	C781	JP Z,TestLowBitsOfCharacter_ReportMatch
	C784	OR $80	Jump ahead to ReadHighByteSource_Store to store it in the token select flag and read the parser.
	C786	JR ReadHighByteSource_Store
Read the high byte of the source, then keep only the bits that are set in the count, then see whether the two values match.
ReadHighByteSource_HighByteSource	C788	LD A,D	Go to TestLowBitsOfCharacter_ReportMatch if the mask does not cover the attribute.
	C789	AND C
	C78A	CP D
	C78B	JP NZ,TestLowBitsOfCharacter_ReportMatch
	C78E	OR $80	Jump ahead to ReadHighByteSource_Store to store it in the token select flag and read the parser.
	C790	JR ReadHighByteSource_Store
ReadHighByteSource_FlipBitsResult	C792	XOR $FF	Invert the mask and keep the bits that are also set in D.
	C794	AND D	Invert the mask and keep the bits that are also set in D.
ReadHighByteSource_TestWorkspaceKeepingBits	C795	AND $7F	Store it in the token select flag at CB79, keeping bits in 7F.
ReadHighByteSource_Store	C797	LD ($CB79),A
	C79A	LD A,($A00B)	Jump to TestLowBitsOfCharacter_ReportMatch if the parser is zero.
	C79D	AND A
	C79E	JP Z,TestLowBitsOfCharacter_ReportMatch
	C7A1	LD HL,$CB7B	Use GetDisplayAddressBasedOnFlag as the pointer.
	C7A4	XOR A	Clear A.
	C7A5	RET	Return.