Zilog Z8F0130 - Manual (Page 33)

eZ8
™
CPU Core
User Manual
UM012820-0810 Address Space
18
specific to your Z8 Encore! device to determine the number of registers
available in the Register File as well as descriptions of the peripheral and
I/O control registers.
CPU Control Registers
Within the 256 registers reserved for control, there are four eZ8 CPU con-
trol registers that are always at the same register addresses. These four
eZ8 CPU control registers (see
Table 6 ) are the Stack Pointer High Byte,
Stack Pointer Low Byte, Register Pointer and Flags registers. For more
information on the operation of the eZ8 CPU control registers, see
Archi-
tectural Overview on page 1.
General-Purpose Registers
Other than the upper 256 registers reserved for control functions, all other
available addresses within the Register File are available for

general-purpose use. Refer to the Zilog Product Specification specific to
your Z8 Encore! device to determine the addresses available.
Register File Organization
The Register File can be accessed as a 4096 byte linear address space
using 12-bit addressing mode, as sixteen 256-byte Register Pages using

8-bit addressing mode, or as sixteen 16-byte Working Register Groups per
Table 6. eZ8 CPU Control Registers
Register

Mnemonic Register Description
Address
(Hex)
FLAGS Flags FFC
RP Register Pointer FFD
SPH Stack Pointer High Byte FFE
SPL Stack Pointer Low Byte FFF