Z89323 Datasheet, PDF (45/61 Pages) Zilog, Inc. – 16-BIT DIGITAL SIGNAL PROCESSORS

PRELIMINARY
Z89323/373/393
16-BIT DIGITAL SIGNAL PROCESSORS
There are eight distinct addressing modes for data transfer.
<pregs>, <hwregs> These two modes are used for simple
loads to and from registers within the chip, such as loading
to the Accumulator, or loading from a pointer register. The
names of the registers need only be specified in the
operand field (destination first, then source).
the RAM is in turn specified by the value in the pointer.
Note that the data pointer can also be used for a memory
access in this manner, but only one “@” precedes the
pointer. In both cases, the memory address stored in RAM
is incremented by one, each time the addressing mode is
used, to allow easy transfer of sequential data from
program memory.
<regind> This mode is used for indirect accesses to the
data RAM. The address of the RAM location is stored in the
pointer. The “@” symbol indicates “indirect” and precedes
the pointer, therefore @P1:1 instructs the processor to
read or write to a location in RAM1, which is specified by
the value in the pointer.
<dregs> This mode is also used for accesses to the data
RAM, but only the lower 16 addresses in either bank. The
4-bit address comes from the status register and the
operand field of the data pointer. Note that data registers
are typically used not for addressing RAM, but loading
data from program memory space.
<memind> This mode is used for indirect accesses to the
program memory. The address of the memory is located
in a RAM location, which is specified by the value in a
pointer. Therefore, @@P1:1 instructs the processor to
read (write is not possible) from a location in memory,
which is specified by a value in RAM, and the location of
<accind> Similar to the previous mode, the address for the
program memory read is stored in the Accumulator. @A in
the second operand field loads the number in memory
specified by the address in A.
<direct> The direct mode allows read or write to data RAM
from the Accumulator by specifying the absolute address
of the RAM in the operand of the instruction. A number
between 0 and 255 indicates a location in RAM0, and a
number between 256 and 511 indicates a location in
RAM1.
<limm> This address mode indicates a long immediate
load. A 16-bit word can be copied directly from the
operand into the specified register or memory.
<simm> This address mode can only be used for immediate
transfer of 8-bit data in the operand to the specified RAM
pointer.
CONDITION CODES
The following Instruction Description defines the condition
codes supported by the DSP assembler. If the instruction
description refers to the <cc> (condition code) symbol in
one of its addressing modes, the instruction will only
execute if the condition is true.
Code
C
EQ
F
IE
MI
NC
NE
NIE
NOV
NU0
Description
Carry
Equal (same as Z)
False
Interrupts Enabled
Minus
No Carry
Not Equal (same as NZ)
Not Interrupts Enabled
Not Overflow
Not User Zero
Code
NU1
NZ
OV
PL
U0
U1
UGE
ULT
Z
Description
Not User One
Not zero
Overflow
Plus (Positive)
User Zero
User One
Unsigned Greater Than or
Equal (Same as NC)
Unsigned Less Than (Same as C)
Zero
DS95DSP0101 Q4/95
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