Calculator User Manual

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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.2 Direct Addressing Mode 6-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.3 Indirect Addressing Mode 6-9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter 6