Load TREG, Accumulate Previous Product, and Move Data
LTD
7-95
Assembly Language Instructions
Syntax
LTD
dma
Direct addressing
LTD
ind [, ARn]
Indirect addressing
Operands
dma:
7 LSBs of the data-memory address
n:
Value from 0 to 7 designating the next auxiliary register
ind:
Select one of the following seven options:
* *+ *– *0+ *0– *BR0+ *BR0–
LTD
dma
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0
1
1
1
0
0
1
0
0
dma
LTD
ind [, ARn]
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
0
1
1
1
0
0
1
0
1
ARU
N
NAR
Note:
ARU, N, and NAR are defined in Section 6.3,
Indirect Addressing Mode (page 6-9).
Execution
Increment PC, then ...
(data-memory address)
→
TREG
(data-memory address)
→
data-memory a 1
(ACC) + shifted (PREG)
→
ACC
Status Bits
Affected by
Affects
PM and OVM
C and OV
Description
TREG is loaded with the contents of the specified data-memory address. The
contents of the PREG, shifted as defined by the PM status bits, are added to
the accumulator, and the result is placed in the accumulator. The contents of
the specified data-memory address are also copied to the next higher data-
memory address.
This instruction is valid for all blocks of on-chip RAM configured as data
memory. The data move function is continuous across the boundaries of con-
tiguous blocks of memory but cannot be used with external data memory or
memory-mapped registers. The data move function is described under the in-
struction DMOV.
Note:
If LTD is used with external data memory, its function is identical to that of
LTA; that is, the previous product will be accumulated, and the TREG will be
loaded from external data memory, but
the data move will not occur.
The carry bit is set (C = 1) if the result of the addition generates a carry and
is cleared (C = 0) if it does not generate a carry.
Opcode
