Usage Note; Tas Instruction; Stm/Ldm Instruction; Notes On Using The Bit Operation Instruction - Renesas H8S/2100 Series Hardware Manual

6-bit single-chip microcomputer

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Section 2 CPU

Usage Note

The registers ER0, ER1 ER4, and ER5b must be used when using the TAS instruction.

Note that the TAS instruction is not generated in the Renesas H8S, H8S/300 series C/C++

Compiler. When using the TAS instruction as a user-defined built-in function, the registers ER0,

ER1 ER4, and ER5b must be used.

The register ER7 cannot be used to push data onto the stack for STM instruction or to pop data off

the stack for LDM instruction stack. To push or pop data in one instruction, the registers that can

be used are two, three, or four as shown in the list below.

Two registers: ER0 to ER1, ER2 to ER3, and ER4 to ER5

Three registers: ER0 to ER2, ER4 to ER6

Four registers: ER0 to ER3

Note that the STM/LDM instruction that contains ER is not generated in the Renesas H8S,

H8S/300 series C/C++ Compiler

Instructions BSET, BCLR, BNOT, BST, and BIST read data in byte units, and write data in byte

units after bit operation. Therefore, attention must be paid when these instructions are used for

ports or registers including write-only bits.

Instruction BCLR can be used to clear the flag in the internal I/O register to 0. If it is obvious that

the flag has been set to 1 by the interrupt processing routine, it is unnecessary to read the flag

Rev. 1.00 May 09, 2008 Page 62 of 954

REJ09B0462-0100