S3C84E5/C84E9/P84E9

INSTRUCTION SET

 

 

6 INSTRUCTION SET

OVERVIEW

The instruction set is specifically designed to support large register files that are typical of most S3C8-series microcontrollers. There are 78 instructions. The powerful data manipulation capabilities and features of the instruction set include:

A full complement of 8-bit arithmetic and logic operations, including multiply and divide

No special I/O instructions (I/O control/data registers are mapped directly into the register file)

Decimal adjustment included in binary-coded decimal (BCD) operations

16-bit (word) data can be incremented and decremented

Flexible instructions for bit addressing, rotate, and shift operations

DATA TYPES

The CPU performs operations on bits, bytes, BCD digits, and two-byte words. Bits in the register file can be set, cleared, complemented, and tested. Bits within a byte are numbered from 7 to 0, where bit 0 is the least significant (right-most) bit.

REGISTER ADDRESSING

To access an individual register, an 8-bit address in the range 0–255 or the 4-bit address of a working register is specified. Paired registers can be used to construct 16-bit data, 16-bit program memory or data memory addresses. For detailed information about register addressing, please refer to Chapter 2, "Address Spaces."

ADDRESSING MODES

There are seven explicit addressing modes: Register (R), Indirect Register (IR), Indexed (X), Direct (DA), Relative (RA), Immediate (IM), and Indirect (IA). For detailed descriptions of these addressing modes, please refer to Chapter 3, "Addressing Modes."

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Samsung S3C84E5 user manual Instruction SET, Data Types, Register Addressing, Addressing Modes