Instruction Set Architecture and Design - Fundamentals of Computer Organization and Architecture - page 24

Memory

Operation Value X

+

Program Counter (PC) operand

Figure 2.9 Illustration of relative addressing mode

However, with autoincrement, the content of the autoincrement register is automati-
cally incremented after accessing the operand. As before, indirection is indicated by
including the autoincrement register in parentheses. The automatic increment of the
register's content after accessing the operand is indicated by including a (

þ ) after

the parentheses. Consider, for example, the instruction LOAD (R auto ) , R i . This

instruction loads register R i with the operand whose address is the content of register
R auto . After loading the operand into register R i , the content of register R auto is
incremented, pointing for example to the next item in a list of items. Figure 2.10
illustrates the autoincrement addressing mode.

þ

Figure 2.10 Illustration of the autoincrement addressing mode