NEC PD78058FY(A) User Manual

ADD A, #2

BR

!1002H

BR

!F702H

ADD A, #1

MOV  B, A

0000H

0080H

Program start

1000H

1002H

F400H

F702H

F7FDH

F7FFH

(1)

(2)

(3)

EFFFH

The example of ROM correction when the instruction at address 1000H “ADD A, #1” is changed to “ADD A, #2”

is as follows.

(1) Branches to address F7FDH when the preset value 1000H in the correction address register 0, 1 (CORAD0,

CORAD1) matches the fetch address value after the main program is started.

(2) Branches to any address (address F702H in this example) by setting the entire-space branch instruction (BR

!addr16) to address F7FDH with the main program.

(3) Returns to the internal ROM program after executing the substitute instruction ADD A, #2.