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EM78P458/459
OTP ROM
4.15 Instruction Set
Each instruction in the instruction set is a 13-bit word divided into an OP code and one or more
operands. Normally, all instructions are executed within one single instruction cycle (one instruction
consists of 2 oscillator periods), unless the program counter is changed by instruction "MOV R2,A",
"ADD R2,A", or by instructions of arithmetic or logic operation on R2 (e.g. "SUB R2,A", "BS(C) R2,6",
"CLR R2", ⋅⋅⋅⋅). In this case, the execution takes two instruction cycles.
In addition, the instruction set has the following features:
(1) Every bit of any register can be set, cleared, or tested directly.
(2) The I/O registers can be regarded as general registers. That is, the same instruction can operate
on I/O registers.
The symbol "R" represents a register designator that specifies which one of the registers (including
operational registers and general-purpose registers) is to be utilized by the instruction. The symbol
"b" represents a bit field designator that selects the value for the bit located in the register "R" that is
affected by the operation. The symbol "k" represents an 8 or 10-bit constant or literal value.
Table 16 The list of the instruction set of EM78P458/459
INSTRUCTION BINARY HEX MNEMONIC OPERATION STATUS AFFECTED
0 0000 0000 0000 0000 NOP No Operation None
0 0000 0000 0001 0001 DAA Decimal Adjust A C
0 0000 0000 0010 0002 CONTW A → CONT None
0 0000 0000 0011 0003 SLEP 0 → WDT, Stop oscillator T,P
0 0000 0000 0100 0004 WDTC 0 → WDT T,P
0 0000 0000 rrrr 000r IOW R A → IOCR None <Note1>
0 0000 0001 0000 0010 ENI Enable Interrupt None
0 0000 0001 0001 0011 DISI Disable Interrupt None
0 0000 0001 0010 0012 RET [Top of Stack] → PC None
0 0000 0001 0011 0013 RETI [Top of Stack] → PC, Enable Interrupt None
0 0000 0001 0100 0014 CONTR CONT → A None
0 0000 0001 rrrr 001r IOR R IOCR → A None <Note1>
0 0000 01rr rrrr 00rr MOV R,A A → R None
0 0000 1000 0000 0080 CLRA 0 → A Z
0 0000 11rr rrrr 00rr CLR R 0 → R Z
0 0001 00rr rrrr 01rr SUB A,R R-A → A Z,C,DC
0 0001 01rr rrrr 01rr SUB R,A R-A → R Z,C,DC
0 0001 10rr rrrr 01rr DECA R R-1 → A Z
0 0001 11rr rrrr 01rr DEC R R-1 → R Z
0 0010 00rr rrrr 02rr OR A,R A ∨ VR → A Z
0 0010 01rr rrrr 02rr OR R,A A ∨ VR → R Z
0 0010 10rr rrrr 02rr AND A,R A & R → A Z
0 0010 11rr rrrr 02rr AND R,A A & R → R Z
0 0011 00rr rrrr 03rr XOR A,R A ⊕ R → A Z
0 0011 01rr rrrr 03rr XOR R,A A ⊕ R → R Z
This specification is subject to change without prior notice. 07.01.2003 (V1.3) 53