User guide

SmartBook for Renesas R8C/Tiny Microcontrollers

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the target bit in the device memory. Bits at the address range 00000H to 01FFFH

can be specified for the boolean operations.

When using address register relative mode, the contents of registers A0 and A1

is used to indicate the target bit from the bit zero position of the memory location

indicated by the base register. However, if the address of the target meant for the

processing exceeds 0FFFFH, all the bits above 16 are ignored and the result is

reset to 00000H. The address range that can be specified by the address registers

extends up to 8192 bytes from the base address.

In the next addressing mode, SB relative, the SB register holds the

reference address to which the base value is added to point out

the target bit position. The base value can be defined in few forms:

a byte, 11 bits and 16 bits. Because of these options, the

possible address ranges are 32, 256 and 8192 bytes from

the static base register. However, if the address of the target

bit exceeds 0FFFFH, all the bits above 16 are ignored and

the result is reset to 00000H.

The FB relative mode is similar to that of SB relative

mode with a difference. When using this mode, the base

value is added with the contents of FB register taking

sign bit also into account. Because of this, the target



 For Ad-

dress register in-

direct mode, contents

of A0, A1 address registers

indicate the number of bits

away from the bit zero at the

address 00000H to point the target

bit in the device memory.



 When us-

ing address register relative mode, the

contents of registers A0 and A1 is used

to indicate the target

bit from the bit zero

position of the memory

location indicated by

the base register.