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5 initial register values – Renesas H8S/2111B User Manual

Page 59

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Rev. 1.00, 05/04, page 25 of 544

Bit Bit

Name

Initial
Value R/W Description

0 C Undefined

R/W

Carry

Flag

Set to 1 when a carry occurs, and cleared to 0
otherwise. Used by

Add instructions, to indicate a carry

Subtract instructions, to indicate a borrow

Shift and rotate instructions, to indicate a carry

The carry flag is also used as a bit accumulator by bit
manipulation instructions.

2.4.5 Initial

Register

Values

The program counter (PC) among CPU internal registers is initialized when reset exception
handling loads a start address from a vector table. The trace (T) bit in EXR is cleared to 0, and the
interrupt mask (I) bits in CCR and EXR are set to 1. The other CCR bits and the general registers
are not initialized. Note that the stack pointer (ER7) is undefined. The stack pointer should
therefore be initialized by an MOV.L instruction executed immediately after a reset.

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