Sherlock: Routine at 51043

51043: 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	51043	JR NZ,ReadHighByteSource_CommandOne	Jump to ReadHighByteSource_CommandOne when the folded attribute is not zero.
	51045	LD A,D	Take the byte in D.
	51046	AND C	Keep only the bits that are set in the count.
	51047	CP D	See whether the two values match.
This entry point is used by the routine at TestSeventhMarker.
ReadHighByteSource_0	51048	JP Z,TestLowBitsOfCharacter_ReportMatch	Go to TestLowBitsOfCharacter_ReportMatch if the masked attribute matches.
	51051	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	51053	CP 1	See whether the attribute is 1.
	51055	JR NZ,ReadHighByteSource_CommandTwo	Jump to ReadHighByteSource_CommandTwo when the attribute is not one.
	51057	LD A,D	See whether any attribute bits are still set.
	51058	AND A	Clear the carry before testing the attribute mask.
	51059	JR Z,ReadHighByteSource_0	Jump to ReadHighByteSource_0 when the attribute mask is clear.
	51061	AND C	Go to ReadHighByteSource_TestWorkspaceKeepingBits if the attribute mask matches nothing.
	51062	JR Z,ReadHighByteSource_TestWorkspaceKeepingBits
	51064	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	51067	CP 2	See whether the attribute is 2.
	51069	JR NZ,ReadHighByteSource_HighByteSource	Jump to ReadHighByteSource_HighByteSource when the attribute is not two.
	51071	LD A,D	Go to TestLowBitsOfCharacter_ReportMatch to return zero if the attribute mask matches nothing.
	51072	AND C
	51073	JP Z,TestLowBitsOfCharacter_ReportMatch
	51076	OR 128	Jump ahead to ReadHighByteSource_Store to store it in the token select flag and read the parser.
	51078	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	51080	LD A,D	Go to TestLowBitsOfCharacter_ReportMatch if the mask does not cover the attribute.
	51081	AND C
	51082	CP D
	51083	JP NZ,TestLowBitsOfCharacter_ReportMatch
	51086	OR 128	Jump ahead to ReadHighByteSource_Store to store it in the token select flag and read the parser.
	51088	JR ReadHighByteSource_Store
ReadHighByteSource_FlipBitsResult	51090	XOR 255	Invert the mask and keep the bits that are also set in D.
	51092	AND D	Invert the mask and keep the bits that are also set in D.
ReadHighByteSource_TestWorkspaceKeepingBits	51093	AND 127	Store it in the token select flag at 52089, keeping bits in 127.
ReadHighByteSource_Store	51095	LD (52089),A
	51098	LD A,(40971)	Jump to TestLowBitsOfCharacter_ReportMatch if the parser is zero.
	51101	AND A
	51102	JP Z,TestLowBitsOfCharacter_ReportMatch
	51105	LD HL,52091	Use GetDisplayAddressBasedOnFlag as the pointer.
	51108	XOR A	Clear A.
	51109	RET	Return.