User guide

37
SmartBook for Renesas R8C/Tiny Microcontrollers
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to generate the effective address. In other two relative addressing modes, the
displacement is added with Frame base register or the Stack pointer along with
the sign bit to generate the effective address. If the result of this addition exceeds
the range 00000H to 0FFFFH, all the bits above 16 are ignored and the address
returns to either 00000H or 0FFFFH. This displacement is mentioned using a
byte.
4.2 Special Instruction Addressing:
In this category, few more addressing options are available:
1. 20 bit absolute addressing.
2. Address register relative with 20 bit displacement.
3. 32 bit address register indirect.
4. 32 bit register direct.
5. Control register direct.
6. Program counter relative.
When using the 20 bit absolute addressing, the data indicated using 20 bits is
treated as the effective address for the operation. The effective range of address
is from 00000H to FFFFFH. The next addressing mode, Address register relative
with displacement generates the effective operating address by adding the defined
20 bit displacement with either of the address registers, A0 or A1. However, if the
addition exceeds FFFFFH, all the bits above 20 are ignored and the result is
reset to 00000H.