Fujitsu FR81 사용자 설명서
FR81 Family
96
FUJITSU MICROELECTRONICS LIMITED
CM71-00105-1E
CHAPTER 6 INSTRUCTION OVERVIEW
6.4
6.4
6.4
Read-Modify-Write type Instructions
Read-Modify-Write type Instructions are those that carry out a series of operations
namely, arithmetic processing in the data read from the memory space and write the
result in the same address of the memory space.
namely, arithmetic processing in the data read from the memory space and write the
result in the same address of the memory space.
IN registers of peripheral functions (I/O Registers), there are bits whose read values are different depending
on instructions that independently carry out read access like LD Instruction and Read-Modify-Write type
Instructions. Such bits have been described in the explanation on registers (I/O Registers) of peripheral
functions.
In case of Read-Modify-Write type Instructions, a different instruction based on EIT processing is not
executed between Read access and Write access of one instruction. This is used for exclusive control that
uses flag or semaphore between programs.
Whether or not an instruction is Read-Modify-Write system Instruction is defined for each instruction. See