UPD75518 NEC, UPD75518 Datasheet - Page 144

• Manufacturer Part Number: UPD75518
• Description: 4 BIT SINGLE-CHIP MICROCOMPUTER
• Manufacturer: NEC

144
8. INSTRUCTION SET
8.1
(1) GETI instruction
The GETI instruction references a two-byte table in the program memory and performs the following
three types of operations. This 1-byte instruction is very useful in reducing the number of program steps.
(a) A subroutine call is made to all the spaces, regarding data in a table as the call address of a call
(b) A branch is made to all the spaces, regarding data in a table as the branch address of a branch
(c) Data in a table is executed as a 2-byte or 1-byte instruction.
The tables to be referenced by a GETI instruction are located at addresses 0020H to 007FH in the program
memory. That is, data can be set in up to 48 tables.
When describing a table address as an operand, describe an even address.
Cautions 1. A two-byte instruction which can be referenced by a GETI instruction must be a two-
PD75518(A) INSTRUCTIONS
instruction.
instruction.
2. When referencing two 1-byte instructions with a GETI instruction, only the combinations
3. Branch and subroutine instructions can be referenced by the GETI instruction only when
machine-cycle instruction. (Except for the BRCB and CALLF instructions)
listed in the table below are valid.
their destination addresses are in the 16K-byte space (0000H to 3FFFH). A branch or
subroutine instruction to an address from 4000H to 7F7FH cannot be referenced by the GETI
instruction.
Instruction of first byte
XCH A,@DL
MOV A,@HL
MOV @HL,A
XCH A,@HL
MOV A,@DE
XCH A,@DE
MOV A,@DL
Instruction of second byte
INCS
DECS
INCS
DECS
INCS
INCS
DECS
INCS
DECS
INCS
INCS
DECS
INCS
DECS
L
L
H
H
HL
E
E
D
D
DE
L
L
D
D
PD75518(A)