Notes On Use Of Bit-Manipulation Instructions - Hitachi H8S/2199 Hardware Manual

Single-chip microcomputer

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Notes on Use of Bit-Manipulation Instructions

The BSET, BCLR, BNOT, BST, and BIST instructions read a byte of data, carry out bit

manipulation, then write back the byte of data. Caution is therefore required when using these

instructions on a register containing write-only bits, or a port.

The BCLR instruction can be used to clear internal I/O register flags to 0. In this case, the

relevant flag need not be read beforehand if it is clear that it has been set to 1 in an interrupt

handling routine, etc.

Rev. 1.0, 02/00, page 46 of 1141