NEC PD754244 Manuel D’Utilisation
CHAPTER 11 INSTRUCTION SET
261
User’s Manual U10676EJ3V0UM
11.4.2 Table reference instructions
MOV XA, @PCDE
Function: XA
←
ROM (PC
11-8
+DE)
Transfers the lower 4 bits of the table data in the program memory addressed when the lower 8 bits (PC
7-0
) of the
program counter (PC) are replaced with the contents of register pair DE, to the A register, and the higher 4 bits to
the X register.
The table address is determined by the contents of the program counter (PC) when this instruction is executed.
The necessary data must be programmed to the table area in advance by using an assembler directive (DB
instruction).
The program counter is not affected by execution of this instruction.
This instruction is useful for successively referencing table data.
Example
PC
11–8
11
8
D
3–0
7
4
E
3–0
3
0
X
3
0
A
3
0
Table data H
7
4
Table data L
3
0
Table address
Program memory