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8051
Architectural Specification and Functional Description
REGISTER·INDIRECT
@R1,@RO
(EXT DATA 0-255)
REGISTER
A
REGISTER-INDIRECT
@DP
(EXT DATA 0-64K)
Figure
2.18.
External Data Memory Move Operations
can
be
moved to any
of
these locations.
Of
particular
interest
is
the Direct Address to Direct Address move
which permits the value in a port to be moved to the
Internal
Data
RAM without using any RB registers
or
the accumulator. The
Data
Pointer register can
be
loaded
with a double-byte immediate value. Also, the
8051's
Boolean Processor can move any Direct Addressed bit to
or
from the carry flag.
The A register can be exchanged with a register in the
selected Register Bank, with a Register-Indirect Addressed
byte in the Internal Data RAM or with a Direct Addressed
byte in the Internal
Data
RAM
or
Special Function Reg-
ister. The least significant nibble
of
the A registt;r can also
be
exchanged with the least significant nibble
of
a Register-
Indirect Addressed byte in the Internal Data RAM. The
exchange operation
is
shown in Figure 2.20
REGISTER
C
REGISTER
R7-RO
DIRECT
Data
DIRECT
Data
REGISTER
R7-RO
REGISTER-INDIRECT
@R1,@RO
REGISTER
A
DIRECT
Data
Figure 2.20. Internal Data Memory Exchange
Operations
2.5.2 Logic Operations
The
8051
permits the logic operations
of
and, or, and
exlusive-or to be performed on the A register by a second
operand which can be immediate value, a register in the
selected Register Bank, a Register-Indirect Addressed
byte
of
Internal
Data
RAM
ora
Direct Addressed byte
of
Internal
Data
RAM
or Special Function Register. In
addition, these logic operations can be performed on a
Direct Addressed byte
of
the Internal
Data
RAM
or
Special Function Register using the A register as the
second operand. Also, use
of
Immediate Addressing with
Direct Addressing permits these logic operations to set,
clear
or
complement any bit anywhere in the Internal
Data
RAM
or
Special Function Registers without
REGISTER
DPTR
16
IMMEDIATE
# data
REGISTER
A
REGISTER-INDIRECT
@R1,@RO
REGISTER-INDIRECT
@SP
Figure 2.19. Internal Data Memory Move Operations
AFN-01488A-19
15