Routines
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C6BE: Test The Graphics Field Of The Display Record
Used by the routine at ProcessDisplayRecord.
Tests the low nibble of the record's value byte against the room graphics.
Low nibble of the record's value byte is clear?
TestLowBitsOfGraphics C6BE LD A,(IY+$01) Read the low nibble of the record's value byte and jump ahead to TestLowBitsOfGraphics_CodeFromFive when it is not zero.
C6C1 AND $0F
C6C3 JR NZ,TestLowBitsOfGraphics_CodeFromFive
TestLowBitsOfGraphics_ReportMatch C6C5 OR %00000001 Reset the zero flag.
C6C7 RET Return.
C6C8 JP ParseInputNumber_ReturnZero Return zero through ParseInputNumber_ReturnZero.
For a graphics code from 5 up to but not including 7, reads the room chosen for the graphics.
TestLowBitsOfGraphics_CodeFromFive C6CB CP $05 Jump ahead to TestLowBitsOfGraphics_CodeBelowThree if the low nibble of the value byte is below 05.
C6CD JR C,TestLowBitsOfGraphics_CodeBelowThree
C6CF CP $07 Jump ahead to TestLowBitsOfGraphics_UseGraphics if the low nibble of the value byte is at least 07.
C6D1 JR NC,TestLowBitsOfGraphics_UseGraphics
C6D3 LD A,($A035) Jump to TestLowBitsOfCharacter_ClearFlag if the room graphics parameter is not FE.
C6D6 CP $FE
C6D8 JP NZ,TestLowBitsOfCharacter_ClearFlag
C6DB LD HL,($A031) Read the display pointer.
C6DE LD A,(IY+$01) Jump to TestLowBitsOfGraphics_TestTopBit unless the low nibble of the value byte is 05.
C6E1 AND $0F
C6E3 CP $05
C6E5 JR NZ,TestLowBitsOfGraphics_TestTopBit
C6E7 BIT 7,L Jump back to TestLowBitsOfGraphics_ReportMatch if bit 7 is clear.
C6E9 JR Z,TestLowBitsOfGraphics_ReportMatch
C6EB JP TestLowBitsOfCharacter_ClearFlag This picture does not match, so give up from TestLowBitsOfCharacter_ClearFlag.
Bit 7 of the graphics pointer selects the next picture.
TestLowBitsOfGraphics_TestTopBit C6EE BIT 7,L Jump back to TestLowBitsOfGraphics_ReportMatch while bit 7 is present.
C6F0 JR NZ,TestLowBitsOfGraphics_ReportMatch
C6F2 JP TestLowBitsOfCharacter_ClearFlag Bit 7 of the graphics pointer is clear, so give up from TestLowBitsOfCharacter_ClearFlag.
For a graphics code below 3, looks the room up and accepts it when the top flag is set.
TestLowBitsOfGraphics_CodeBelowThree C6F5 CP $03 Jump ahead to TestLowBitsOfGraphics_TestMarker if the low nibble of the value byte is at least 03.
C6F7 JR NC,TestLowBitsOfGraphics_TestMarker
C6F9 LD A,($A035) Read the room graphics parameter, then call FetchLocationDataPointer to look up this room.
C6FC CALL FetchLocationDataPointer
C6FF BIT 7,(IX+$00) Jump to TestLowBitsOfCharacter_ClearFlag if a marker on the record's flag byte is clear.
C703 JP Z,TestLowBitsOfCharacter_ClearFlag
TestLowBitsOfGraphics_TestMarker C706 BIT 0,(IY+$01) Jump to TestLowBitsOfGraphics_ReportMatch if bit 0 of the value byte is clear.
C70A JR Z,TestLowBitsOfGraphics_ReportMatch
C70C LD A,($A035) Read the room graphics parameter and call FindObjectByFieldTwo to find an object by field two.
C70F CALL FindObjectByFieldTwo
C712 CP $FF Jump back to TestLowBitsOfCharacter_ClearFlag if the entry is the end marker.
C714 JP Z,TestLowBitsOfCharacter_ClearFlag
C717 JR TestLowBitsOfGraphics_ReportMatch The entry is not the end marker, so return non-zero from TestLowBitsOfGraphics_ReportMatch.
Read the room graphics parameter and keep it for the picture.
TestLowBitsOfGraphics_UseGraphics C719 LD A,($A035) Read the room graphics parameter, store it in the room parameter at CB7A and keep it in C.
C71C LD ($CB7A),A
C71F LD C,A
C720 LD A,(IY+$01) Return if TestSeventhMarker returns zero.
C723 CALL TestSeventhMarker
C726 RET Z
C727 BIT 4,(IY+$00) Jump to TestLowBitsOfCharacter_ReportMatch if bit 4 of the record flags is clear.
C72B JP Z,TestLowBitsOfCharacter_ReportMatch
C72E LD A,(IY+$02) Read record bytes 02 and 05.
C731 LD L,(IY+$05)
C734 LD H,(IY+$06) Read record byte 06.
C737 BIT 6,(IY+$00) Jump to TestLowBitsOfGraphics_TestAttribute unless bit 6 of the record flags is set.
C73B JR Z,TestLowBitsOfGraphics_TestAttribute
C73D LD A,(IY+$04) With a handler word present, read record bytes 04 and 07 instead.
C740 LD L,(IY+$07)
C743 LD H,(IY+$08) Read record byte 08.
TestLowBitsOfGraphics_TestAttribute C746 LD B,A Use that byte as the count and call ReadObjectAttribute_LooksObjectFolds to test the object attribute.
C747 CALL ReadObjectAttribute_LooksObjectFolds
C74A RET NZ Return if ReadObjectAttribute_LooksObjectFolds does not match the attribute.
C74B JP TestLowBitsOfCharacter_MarkMatched The attribute matched, so record it from TestLowBitsOfCharacter_MarkMatched.
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