Hardware manual

Microcomputer Technical Q&A
17
Q&A No.: QAH8S-016
Category: Instruction
Subject: TAS Instruction
Question
What is the meaning of the test and set instruction (TAS)?
Answer
The TAS instruction test memory contents, then sets the most significant bit (bit 7) to 1. This is a
read-modify-write instruction, and the bus cannot be released during these operations.
Applicable Products
Applicability Series Applicability Series Applicability Series
Yes Entire H8S Series H8S/2655 H8S/2350
H8S/2355 H8S/2357 H8S/2345
H8S/2245 H8S/2148 H8S/2144
H8S/2138 H8S/2134 H8S/2128
H8S/2124 — — — —