ST10 FAMILY PROGRAMMING MANUAL
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SHR
Shift Right
Syntax
SHR op1,
op2
Operation
(count) <--
(op2)
(C) <--
0
(V) <--
0
DO WHILE (count)
≠
0
(V)
<-- (C) v (V)
(C) <--
(op1
0
)
(op1
n
) <--
(op1
n+1
) [n=0...14]
(op1
15
) <--
0
(count)
<-- (count) - 1
END WHILE
Data Types
WORD
Description
Shifts the destination word operand op1 right by as many times as specified by the source operand op2.
The most significant bits of the result are filled with zeros accordingly. Since the bits shifted out effectively
represent the remainder, the Overflow flag is used instead as a Rounding flag. This flag together with the
Carry flag helps the user to determine whether the remainder bits lost were greater than, less than or
equal to one half an least significant bit. Only shift values between 0 and 15 are allowed. When using a
GPR as the count control, only the least significant 4 bits are used.
Flags
Addressing Modes
E
Z
V
C
N
0
*
S
S
*
E
Always cleared.
Z
Set if result equals zero. Cleared otherwise.
V
Set if in any cycle of the shift operation a ‘1’ is shifted out of the carry flag. Cleared for a shift
count of zero.
C
The carry flag is set according to the last least significant bit shifted out of op1. Cleared for a
shift count of zero.
N
Set if the most significant bit of the result is set. Cleared otherwise.
Mnemonic
Format
Bytes
SHR
Rw
n
, Rw
m
6C nm
2
SHR
Rw
n
, #data
4
7C #n
2
Содержание ST10 Series
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