
<
2
.75
7UGT U/CPWCN
+PUVTWEVKQP5GV
=L/2*
7/<:
Assembly Language Syntax
For proper instruction execution, assembly language syntax requires that the destination and source be spec-
ified as
dst,
src
(in that order). The following instruction descriptions show the format of the object code
produced by the assembler. This binary format should be followed by users who prefer manual program
coding or who intend to implement their own assembler. Other third party assemblers can differ. Please
consult the software user’s manual for detailed information.
Example: The contents of registers
43H
and
08H
are added, and the result is stored in
43H
. The assembly
syntax and resulting object code are:
In general, whenever an instruction format requires an 8-bit register address, that address can specify any
register location in the range 0 - 255. When using working registers (R0-R15), a 4-bit address is used. If a
working register is used and an 8-bit address is required by the assembler, an E is pre-pended to the 4-bit
working register address. If, in the above example, the source register is a working register, the assembly
syntax and resulting object code are:
NOTES:
1.
Note that the 4-bit address R8 was expanded to 8-bits by pre-pending
EH
. This expansion occurs any
time a 4-bit address isspecified for an instruction that takes 8-bit operands.
2.
See the device product specification to determine the exact register file range available. The register
file size varies by device type
Z8
PLUS
INSTRUCTION SUMMARY
The instructions marked with this symbol (†) have an identical set of addressing modes, which are encoded
for brevity. The upper nibble is described in Table 3-14, and the lower nibble is represented by
[].
The
second nibble’s value is described in Table 3-15, and is found beside the applicable addressing mode pair.
For example, the op code of an ADC instruction using the addressing modes
r
(destination) and
Ir
(source)
is
13H.
ASM:
ADD
43H,
08H
(ADD dst, src)
OBJ:
04
08
43
(OPC src, dst)
ASM:
ADD
43H,
R8
(ADD dst, src)
OBJ:
04
E8
43
(OPC src, dst)