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SER
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S
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ANUAL
Z
ILOG
The four instruction formats are shown in Tables A-1
through A-4. Within each format, several different configu-
rations are possible, depending on whether the instruction
involves addressing mode escape bytes, addresses, dis-
placements, or immediate data. In Table A-1 through A-4,
the symbol “A.esc” is used to indicate the presence of an
addressing mode escape byte, “O.esc” is used to indicate
the presence of an opcode escape byte, “disp.” is an
abbreviation for displacement and “addr.” is an abbrevia-
tion for address.
Table A-1. Format 1 Instructions Encodings
Instruction Format Assembly Hexadecimal
Opcode LD A,C 79
Opcode 2-byte Address LD A,(addr) 3A addr (L) addr (H)
Opcode 1-byte Displacement DJNZ addr 10 disp
Opcode Immediate LD E,n 1E n
A.esc Opcode 2-byte Address LD IX,(addr) DD 2A addr (L) addr (H)
A.esc Opcode 1-byte Displacement LD A, (IX+d) DD 7E disp
A.esc Opcode Immediate LD IX,nn DD 21 n(L) n(H)
A.esc Opcode 1-byte Displacement Immediate LD (IY+d),n FD 36 d n
Note: “A.esc” is an addressing mode escape byte, and either 0DDH or 0FDH.
Table A-2. Format 2 Instructions Encodings
Instruction Format Assembly Hexadecimal
Opcode LD A,C 79
O.esc Opcode Immediate (1 byte) TST n ED 64 n
O.esc Opcode Immediate (2 bytes) LD (BC),nn ED 06 n(L) n(H)
O.esc Opcode Address (2 bytes) LD BC,(addr) ED 4B addr (L) addr (H)
O.esc Opcode Displacement (1 byte) CALR e ED CD e
O.esc Opcode Displacement (2 bytes) JR ee DD 18 d(L) d(H)
O.esc Opcode Displacement (3 bytes) JR eee FD 18 d(L) d(M) d(H)
Note: “O.esc” is an opcode escape byte, and either 0DDH, 0EDH or 0FDH.
Table A-3. Format 3 Instruction Encoding
CB Opcode RLC (HL) CB 06
A.esc CB 1 Byte Displacement Opcode RLC (IX+d) DD CB d 06
Note: “A.esc” is an addressing mode escape byte, and either 0DDH or 0FDH.
Table A-4. Format 4 Instruction Encoding
ED CB Opcode RRCW BC ED CB 08
ED CB Opcode Immediate MULTW nn ED CB 97 n(L) n(H)
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