Basic Instruction Formats - Renesas H8S/2633 Series Hardware Manual

2.6.4

Basic Instruction Formats

The H8S/2633 Series instructions consist of 2-byte (1-word) units. An instruction consists of an
operation field (op field), a register field (r field), an effective address extension (EA field), and a
condition field (cc).
(1) Operation Field: Indicates the function of the instruction, the addressing mode, and the
operation to be carried out on the operand. The operation field always includes the first 4 bits of
the instruction. Some instructions have two operation fields.
(2) Register Field: Specifies a general register. Address registers are specified by 3 bits, data
registers by 3 bits or 4 bits. Some instructions have two register fields. Some have no register
field.
(3) Effective Address Extension: Eight, 16, or 32 bits specifying immediate data, an absolute
address, or a displacement.
(4) Condition Field: Specifies the branching condition of Bcc instructions.
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