UM001600-Z8X0599
11-1
U
SER
’
S
M
ANUAL
C
HAPTER
11
A
DDRESSING
M
ODES
11.1 INTRODUCTION
11.1.1 Z8 Addressing Modes
The Z8 microcontroller provides six addressing modes:
Register (R)
Indirect Register (IR)
Indexed (X)
Direct (D)
Relative (RA)
Immediate (IM)
With the exception of immediate data and condition codes,
all operands are expressed as register file, Program Mem-
ory, or Data Memory addresses. Registers are accessed
using 8-bit addresses in the range of 00H-FFH. The Pro-
gram Memory or Data Memory is accessed using 16-bit
addresses (register pairs) in the range of 0000H-FFFFH.
Working Registers are accessed using 4-bit addresses in
the range of 0-15 (0H-FH). The address of the register be-
ing accessed is formed by the combination of the upper
four bits in the Register Pointer (R253) and the 4-bit work-
ing register address supplied by the instruction.
Registers can be used in pairs to designate 16-bit values
or memory addresses. A Register Pair must be specified
as an even-numbered address in the range of 0, 2,...., 14
for Working Registers, or 4, 6,....238 for actual registers.
In the following definitions of Z8 Addressing Modes, the
use of'register' can also imply register pair, working regis-
ter, or working register pair, depending on the context.
Note:
See the product data sheet for exact program, data,
and register memory types and address ranges available.