Section 2 CPU
2.1 Overview
The H8/300L CPU has sixteen 8-bit general registers, which can also be paired as eight 16-bit
registers. Its concise instruction set is designed for high-speed operation.
2.1.1 Features
Features of the H8/300L CPU are listed below.
•
General-register architecture
Sixteen 8-bit general registers, also usable as eight 16-bit general registers
•
Instruction set with 55 basic instructions, including:
— Multiply and divide instructions
— Powerful bit-manipulation instructions
•
Eight addressing modes
— Register direct
— Register indirect
— Register indirect with displacement
— Register indirect with post-increment or pre-decrement
— Absolute address
— Immediate
— Program-counter relative
— Memory indirect
•
64-kbyte address space
•
High-speed operation
— All frequently used instructions are executed in two to four states
— High-speed arithmetic and logic operations
— 8- or 16-bit register-register add or subtract: 0.67 µs*
— 8
×
8-bit multiply:
4.67 µs*
— 16 ÷ 8-bit divide:
4.67 µs*
Note: * These values are at ø = 3 MHz.
•
Low-power operation modes
SLEEP instruction for transfer to low-power operation
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