Datasheet

ST72321Rx ST72321ARx ST72321Jx
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INSTRUCTION SET OVERVIEW (Cont’d)
11.1.6 Indirect Indexed (Short, Long)
This is a combination of indirect and short indexed
addressing modes. The operand is referenced by
its memory address, which is defined by the un-
signed addition of an index register value (X or Y)
with a pointer value located in memory. The point-
er address follows the opcode.
The indirect indexed addressing mode consists of
two submodes:
Indirect Indexed (Short)
The pointer address is a byte, the pointer size is a
byte, thus allowing 00 - 1FE addressing space,
and requires 1 byte after the opcode.
Indirect Indexed (Long)
The pointer address is a byte, the pointer size is a
word, thus allowing 64 Kbyte addressing space,
and requires 1 byte after the opcode.
Table 27. Instructions Supporting Direct,
Indexed, Indirect and Indirect Indexed
Addressing Modes
11.1.7 Relative mode (Direct, Indirect)
This addressing mode is used to modify the PC
register value, by adding an 8-bit signed offset to
it.
The relative addressing mode consists of two sub-
modes:
Relative (Direct)
The offset is following the opcode.
Relative (Indirect)
The offset is defined in memory, which address
follows the opcode.
Long and Short
Instructions
Function
LD Load
CP Compare
AND, OR, XOR Logical Operations
ADC, ADD, SUB, SBC
Arithmetic Additions/Sub-
stractions operations
BCP Bit Compare
Short Instructions Only Function
CLR Clear
INC, DEC Increment/Decrement
TNZ Test Negative or Zero
CPL, NEG 1 or 2 Complement
BSET, BRES Bit Operations
BTJT, BTJF
Bit Test and Jump Opera-
tions
SLL, SRL, SRA, RLC,
RRC
Shift and Rotate Operations
SWAP Swap Nibbles
CALL, JP Call or Jump subroutine
Available Relative
Direct/Indirect
Instructions
Function
JRxx Conditional Jump
CALLR Call Relative