Z8F0113HJ005EG Datasheet, PDF (190/245 Pages) Zilog, Inc. – High-Performance 8-Bit Microcontrollers

Z8 Encore! XP^® F0823 Series
Product Specification
175
Assembly Language Source Program Example
JP START
START:
LD R4, R7
LD 234H, #%01
; Everything after the semicolon is a comment.
; A label called ‘START’. The first instruction (JP START) in this
; example causes program execution to jump to the point within the
; program where the START label occurs.
; A Load (LD) instruction with two operands. The first operand,
; Working Register R4, is the destination. The second operand,
; Working Register R7, is the source. The contents of R7 is
; written into R4.
; Another Load (LD) instruction with two operands.
; The first operand, Extended Mode Register Address 234H,
; identifies the destination. The second operand, Immediate Data
; 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 
following instruction examples illustrate the format of some basic assembly instructions
and the resulting object code produced by the assembler. You must follow this binary for-
mat 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 shown in Table 106.
Table 106. Assembly Language Syntax Example 1
Assembly Language Code
Object Code
ADD 43H, 08H (ADD dst, src)
04 08 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
shown in Table 107.
PS024315-1011
PRELIMINARY
Assembly Language Syntax