Based Addressing; Stack Addressing - NEC mPD789026 Subseries User Manual

3.4.6 Based addressing

[Function]
8-bit immediate data is added to the contents of the base register, that is, the HL register pair, and the sum is
used to address the memory. Addition is performed by expanding the offset data as a positive number to 16
bits. A carry from the 16th bit is ignored. This addressing can be carried out for all the memory spaces.
[Operand format]
Identifier
−
[HL+byte]
[Example]
MOV A, [HL+10H]; When setting byte to 10H

3.4.7 Stack addressing

[Function]
The stack area is indirectly addressed with the stack pointer (SP) contents.
This addressing method is automatically employed when the PUSH, POP, subroutine call, and RETURN
instructions are executed or the register is saved/restored upon generation of an interrupt request.
Stack addressing enables to access the internal high-speed RAM area only.
[Example]
In the case of PUSH DE
68
CHAPTER 3 CPU ARCHITECTURE
Instruction Code 0 0
0 0
Instruction Code 1 0
User's Manual U11919EJ3V0UM00
Description
1 0 1 1 0 1
0 1 0 0 0 0
1 0 1 0 1 0