eZ8 CPU
User Manual
UM012811-0904
Z8 Compatibility
9
Z8 Compatibility
OVERVIEW
The eZ8 CPU is an extension and improvement of ZiLOG’s popular, easy-to-use, and
powerful Z8
®
CPU architecture. Users who have experience programming the Z8
®
CPU
will have no difficulty adapting to the eZ8 CPU. All users will appreciate the new instruc-
tions that improve execution for programs developed in high-level programming lan-
guages such as C.
ASSEMBLY LANGUAGE COMPATIBILITY
The eZ8 CPU executes all Z8
®
assembly language instructions other than WDH (Watch-
Dog Timer Enable During HALT Mode at opcode 4FH). Users with existing Z8
®
assem-
bly code can easily compile their code to use the eZ8 CPU. The assembler for the eZ8
CPU is available for download from
www.zilog.com.
NEW INSTRUCTIONS
The eZ8 CPU features many new instructions to increase processor efficiency and allow
access to the expanded 4KB Register File. There are two classes of new instructions avail-
able in the eZ8 CPU - New Function instructions and Extended Addressing instructions.
New Function Instructions
Table 3 lists the instructions that provide new functionality.
Table 3. New Function Instructions
Mnemonic
Instruction Description
ATM
Atomic Execution
BCLR
Bit Clear
BIT
Bit Set or Clear
BRK
Break
BSET
Bit Set
BSWAP
Bit Swap