Routines
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A2BD: Extract Object Attributes
Used by the routines at ProcessObjectDisplay, ProcessObject_Display, ProcessDisplayPointer and ProcessDisplayAction.
Input
IX Pointer to object data
Extract the first attribute value from bit-packed object data.
ExtractObjectAttributes A2BD LD A,(IX+$05) A=*IX+05 (load byte from offset +5).
A2C0 RRCA Shift right by 4 bits (extract low nibble from offset +5).
A2C1 RRCA
A2C2 RRCA
A2C3 RRCA
A2C4 AND %00001111 Keep only bits 0-3.
A2C6 LD C,A C=A (store the low nibble).
A2C7 LD A,(IX+$07) A=*IX+07 (load byte from offset +7).
A2CA AND %11110000 Keep only bits 4-7 (extract high nibble from offset +7).
A2CC ADD A,C A+=C (combine high and low nibbles).
A2CD LD ($A01E),A Write A to *A01E (store the first attribute value).
Extract the second attribute value from bit-packed object data.
A2D0 LD A,(IX+$01) A=*IX+01 (load byte from offset +1).
A2D3 RRCA Shift right by 4 bits (extract low nibble from offset +1).
A2D4 RRCA
A2D5 RRCA
A2D6 RRCA
A2D7 AND %00001111 Keep only bits 0-3.
A2D9 LD C,A C=A (store the low nibble).
A2DA LD A,(IX+$03) A=*IX+03 (load byte from offset +3).
A2DD AND %11110000 Keep only bits 4-7 (extract high nibble from offset +3).
A2DF ADD A,C A+=C (combine high and low nibbles).
A2E0 LD ($A01D),A Write A to *ObjectAttributeValue (store the second attribute value).
A2E3 RET Return.
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