Z8F6421PM020SC Datasheet, PDF (254/299 Pages) Zilog, Inc. – High Performance 8-Bit Microcontrollers Z8 Encore-R 64K Series

Z8 Encore!^® 64K Series
Product Specification
234
; value 01H, is the source. The value 01H is written into the
; Register at address 234H.
Assembly Language Syntax
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
by users that prefer manual program coding or intend to implement their 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
Assembly Language Code ^ADD
Object Code
04
43H,
08
08H (ADD dst, src)
43 (OPC src, dst)
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
Assembly Language Code ^{ADD 43H, R8 (ADD dst, src)}
Object Code
04
E8
43 (OPC src, dst)
See the device-specific Product Specification to determine the exact register file range
available. The register file size varies, depending on the device type.
eZ8 CPU Instruction Notation
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 Table 121.
PS019915-1005
eZ8 CPU Instruction Set