6-1
Addressing Modes
Addressing Modes
This chapter explains the three basic memory addressing modes used by the
’C2xx instruction set. The three modes are:
-
Immediate addressing mode
-
Direct addressing mode
-
Indirect addressing mode
In immediate addressing, a constant to be manipulated by the instruction is
supplied directly as an operand of that instruction. Two types of immediate
addressing are available—short and long. In short-immediate addressing, an
8-, 9-, or 13-bit operand is included in the instruction word. Long-immediate
addressing uses a 16-bit operand.
When you need to access data memory, you can use direct or indirect addres-
sing. Direct addressing concatenates seven bits of the instruction word with
the nine bits of the data-memory page pointer (DP) to form the 16-bit data
memory address. Indirect addressing accesses data memory through one of
eight 16-bit auxiliary registers.
Topic
Page
6.1
Immediate Addressing Mode
6-2
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6.2
Direct Addressing Mode
6-4
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6.3
Indirect Addressing Mode
6-9
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Chapter 6
