Fujitsu F2MC-8FX Manual Do Utilizador

43

CHAPTER 5  CPU SOFTWARE ARCHITECTURE

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This instruction is used for branching to an address where the contents of the accumulator (A) are used. The

contents of one of the N jump addresses arranged in table form is selected and transferred to the

accumulator. Executing this instruction enables the N-branch processing.

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This instruction is used for performing the opposite operation to JMP @A. In other words, it stores, the

contents of the program counter (PC) in the accumulator (A). When this instruction is executed in the main

routine and a specific subroutine is to be called, make sure that the contents of the accumulator are the

specified value in the subroutine, that is the branch is from the expected section, enabling a decision on

crash.

When this instruction is executed, the contents of the accumulator are the same as those of the address

where the code for the next instruction is stored and not the address where the code for this instruction is

stored. The above example shows that the value 1234

H

 stored in the accumulator agrees with that of the

address where the instruction code next to MOVW A, PC is stored.

Before execution

After execution

1234

H

1234

H

1234

H

XXXX

H

New PC

Old PC

 [Example]

JMP @A

A

 [Example]

MOVW A, PC

Before execution

After execution

XXXX

H

1234

H

1234

H

1234

H

A

A

New PC

Old PC