190
256-bit to 8-bit Encoder DMPX(77)
operates as a 256-bit to 8-bit encoder when the
leftmost digit of C is
set to 1.
When
the execution condition is OFF
, DMPX(77) is
not executed. When the exe
-
cution condition is ON, DMPX(77) determines the position of the highest (left-
most)
ON bit in the group of 16 source words from S to S+15 or S+16 to S+31,
encodes it into a two-digit hexadecimal value corresponding to the location of
the
bit among the
256 bits in the group, then transfers the hexadecimal value to
the
specified byte in R. The byte to receive the result is specified in C, which also
specifies the number of bytes to be encoded.
Control Word The
digits of C are set as shown below
. Set the leftmost digit of C to
1 to specify
256-bit to 8-bit decoding.
Specifies
the first byte in R to receive converted data (0 or 1).
0: Rightmost byte
1: Leftmost byte
Number of bytes to be encoded (0 or 1).
0: 1 byte
1: 2 bytes
Not used. Set to 0.
A value of 1 specifies 256-bit to 8-bit encoding.
Digit number:
3210
Three
possible C values and the conversions that they produce are shown be
-
low. (In R, 0 indicates the rightmost byte and 1 indicates the leftmost byte.)
0
1
R
C:
1000
C: 1010
C: 101
1
S to S+15
S+16 to S+31
0
1
R
S to S+15
S+16 to S+31
0
1
R
S to S+15
S+16 to S+31
The
following is an example of a one-byte encode operation to the rightmost byte
of R (C would be 1000 in this case).
. . .
S+14
Bit
15
Bit
00
010011
S+15
Bit
15
Bit
00
00110111011000
Result word
FB
1
. . . . . .
S
Bit
15
Bit
00
0001111
Bit FB (bit 251 of 0 to 255) is the highest ON bit of the
16-word group, so FB is written to the rightmost bit of R.
Flags ER: Undefined control word.
The source words are not all in the same data area.
Content of a source word is zero. (There isn’t an ON bit in the source
words.)
Indirectly
addressed DM word
is non-existent. (Content of
∗
DM word is
not BCD, or the DM area boundary has been exceeded.)
Data Conversion Section 5-18
To Next Page
Loading...
Need help?
General
