128
CHAPTER 5 CPU ARCHITECTURE
5.4.8 Based indexed addressing
[Function]
This addressing addresses the memory by adding the contents of the HL register, which is used as a base register,
to the contents of the B or C register specified in the instruction word, and by using the result of the addition.
The HL, B, and C registers to be accessed are registers in the register bank specified by the register bank select
flags (RBS0 and RBS1). The addition is performed by extending the contents of the B or C register to 16 bits
as a positive number. A carry from the 16th bit is ignored. This addressing can be carried out for all the memory
spaces.
[Operand format]
Identifier
Description
—
[HL + B], [HL + C]
[Description example]
In the case of MOV A, [HL + B]
Operation code
1 0 1 0 1 0 1 1
5.4.9 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/reset upon generation of an interrupt request.
Stack addressing enables to address the internal high-speed RAM area only.
[Description example]
In the case of PUSH DE
Operation code
1 0 1 1 0 1 0 1
Summary of Contents for PD78052
Page 2: ...2 MEMO ...
Page 8: ...8 MEMO ...
Page 16: ...16 MEMO ...
Page 36: ...36 MEMO ...
Page 158: ...158 MEMO ...
Page 174: ...174 MEMO ...
Page 240: ...240 MEMO ...
Page 260: ...260 MEMO ...
Page 340: ...340 MEMO ...
Page 392: ...392 MEMO ...
Page 438: ...438 MEMO ...
Page 482: ...482 CHAPTER 20 REAL TIME OUTPUT PORT MEMO ...
Page 510: ...510 MEMO ...
Page 524: ...524 MEMO ...
Page 560: ...560 MEMO ...
Page 576: ...576 MEMO ...
Page 598: ...598 MEMO ...
Page 602: ...602 MEMO ...