ST72361xx-Auto
Instruction set
18.1.2
Immediate
Immediate instructions have 2 bytes, the first byte contains the opcode, the second byte
contains the operand value.
Immediate instruction
LD
CP
BCP
AND, OR, XOR
ADC, ADD, SUB, SBC
Function
Load
Compare
Bit compare
Logical operations
Arithmetic operations
18.1.3
18.1.4
18.1.5
Direct
In direct instructions, the operands are referenced by their memory address.
The direct addressing mode consists of two submodes:
Direct (short)
The address is a byte, thus requires only one byte after the opcode, but only allows 00 - FF
addressing space.
Direct (long)
The address is a word, thus allowing 64 Kbyte addressing space, but requires 2 bytes after
the opcode.
Indexed (no offset, short, long)
In this mode, the operand is referenced by its memory address, which is defined by the
unsigned addition of an index register (X or Y) with an offset.
The indirect addressing mode consists of three submodes:
Indexed (no offset)
There is no offset, (no extra byte after the opcode), and allows 00 - FF addressing space.
Indexed (short)
The offset is a byte, thus requires only one byte after the opcode and allows 00 - 1FE
addressing space.
Indexed (long)
The offset is a word, thus allowing 64 Kbyte addressing space and requires 2 bytes after the
opcode.
Indirect (short, long)
The required data byte to do the operation is found by its memory address, located in
memory (pointer).
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