213
16-bit to 4-bit Encoder DMPX(77) operates as a 16-bit to 4-bit encoder when the leftmost digit of C is 0.
When the execution condition is OFF, DMPX(77) is not executed. When the
execution condition is ON, DMPX(77) determines the position of the highest ON
bit in S, encodes it into single-digit hexadecimal value corresponding to the bit
number, then transfers the hexadecimal value to the specified digit in R. The dig-
its to receive the results are specified in C, which also specifies the number of
digits to be encoded.
Control Word The digits of C are set as shown below. Set the leftmost digit of C to 0 to specify
16-bit to 4-bit encoding.
Specifies the first digit in R to receive converted data (0 to 3).
Number of words to be converted (0 to 3).
0: 1 word
1: 2 words
2: 3 words
3: 4 words
Not used. Set to 0.
A value of 0 specifies 16-bit to 4-bit encoding.
Digit number: 3210
Some example C values and the word-to-digit conversions that they produce
are shown below.
0
1
2
3
R
C: 0011
S
S + 1
0
1
2
3
S
S + 1
S + 2
S + 3
C: 0030
R
S
S + 1
S + 2
S + 3
0
1
2
3
C: 0032 R
C: 0013
0
1
2
3
S
S + 1
R
The following is an example of a one-digit encode operation to digit number 1 of
R, i.e., here C would be 0001.
Result word
First source word
C
0001000100010110
C transferred to indicate bit number 12 as
the highest ON bit.
Up to four digits from four consecutive source words starting with S may be en-
coded and the digits written to R in order from the designated first digit. If more
digits are designated than remain in R (counting from the designated first digit),
the remaining digits will be placed at digits starting back at the beginning of R.
The final word to be converted (S plus the number of digits to be converted) must
be in the same data area as SB.
Data Conversion Section 5-18