Hardware manual
Rev. 3.0, 09/98, page 15 of 361
Section 2 CPU
2.1 Overview
The H8/338 Series has the H8/300 CPU: a fast central processing unit with eight 16-bit general
registers (also configurable as 16 eight-bit registers) and a concise instruction set designed for
high-speed operation.
2.1.1 Features
The main features of the H8/300 CPU are listed below.
•
Two-way register configuration
Sixteen 8-bit general registers, or
Eight 16-bit general registers
•
Instruction set with 57 basic instructions, including:
Multiply and divide instructions
Powerful bit-manipulation instructions
•
Eight addressing modes
Register direct (Rn)
Register indirect (@Rn)
Register indirect with displacement (@(d:16, Rn))
Register indirect with post-increment or pre-decrement (@Rn+ or @
−
Rn)
Absolute address (@aa:8 or @aa:16)
Immediate (#xx:8 or #xx:16)
PC-relative (@(d:8, PC))
Memory indirect (@@aa:8)
•
Maximum 64K-byte address space
•
High-speed operation
All frequently-used instructions are executed in two to four states
The maximum clock rate is 10MHz
8- or 16-bit register-register add or subtract: 0.2µs
8
×
8-bit multiply: 1.4µs
16
÷
8-bit divide: 1.4µs
•
Power-down mode
SLEEP instruction