z8f1621 ZiLOG Semiconductor, z8f1621 Datasheet - Page 252

• Manufacturer Part Number: z8f1621
• Description: High Performance 8-bit Microcontrollers
• Manufacturer: ZiLOG Semiconductor

Assembly Language Syntax
eZ8 CPU Instruction Notation
PS019921-0308
For proper instruction execution, eZ8 CPU assembly language syntax requires that the
operands be written as ‘destination, source’. After assembly, the object code usually has
the operands in the order ‘source, destination’, but ordering is opcode-dependent. The fol-
lowing instruction examples illustrate the format of some basic assembly instructions and
the resulting object code produced by the assembler. This binary format must be followed
if you prefer manual program coding or intend to implement your own assembler.
Example 1: If the contents of Registers 43H and 08H are added and the result is stored in
43H, the assembly syntax and resulting object code is:
Assembly Language Syntax Example 1
Example 2: In general, when an instruction format requires an 8-bit register address, that
address can specify any register location in the range 0–255 or, using Escaped Mode
Addressing, a Working Register R0 - R15. If the contents of Register 43H and Working
Register R8 are added and the result is stored in 43H, the assembly syntax and resulting
object code is:
Assembly Language Syntax Example 2
Refer to the device-specific Product Specification to determine the exact register file range
available. The register file size varies, depending on the device type.
In the eZ8 CPU Instruction Summary and Description sections, the operands, condition
codes, status Flags, and address modes are represented by a notational shorthand that is
described in
Assembly Language
Code
Object Code
Assembly Language
Code
Object Code
Table
122.
ADD
04
04
ADD
43H,
43H,
08
E8
08H
43
R8
43
(ADD dst, src)
(OPC src, dst)
(ADD dst, src)
(OPC src, dst)
Z8 Encore! XP
Product Specification
eZ8
™
®
CPU Instruction Set
F64XX Series
238