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2 Instructions
CP1E CPU Unit Instructions Reference Manual(W483)
Conversion Instructions
2
DMPX
256-to-8 bit conversion
C: Control word
Operand Specifications
Flags
Function

DMPX(077) can perform 16-to-4 bit or 256-to-8 bit conversions. Set the leftmost digit of C to 0 to specify

16-to-4 bit conversion and set it to 1 to specify 256-to-8 bit conversion.

16-to-4 bit Conversion

When the fourth (leftmost) digit of C is 0, DMPX(077) finds the locations of the leftmost or rightmost ON

bits in up to 4 source words and writes these locations to R beginning with the specified digit.

S: First Source Word

S+15 to S: 1st digit of digits to be encoded

S+31 to S+16: 2nd digit of digits to be encoded

R: Result Word

Note The source words must be in the same

data area.
Area Word addresses Indirect DM addresses Constants CF Pulse bits TR bits
CIO WR HR AR T C DM @DM *DM
S,R OK OK OK OK OK OK OK OK OK --- --- --- ---
COK
Name Label Operation
Error Flag P_ER •ON if any of the source words contains 0000 hex (i.e., no bit to encode).
•ON if C is not within the specified ranges.
•OFF in all other cases.
R
815
Digit 1 Digit 0
07
The results of encoding of S to S+15, S+16 to
S+31 are stored from the starting digit going
left (returns to digit 0 after digit 1).
C1
Specifies the first digit/byte to receive converted data.
0 or 1 (byte 0 or 1)
Number of digits/bytes to be converted
0 or 1 (1 or 2bytes)
8111215
ln
03
47
Bit to encode
0: Leftmost bit (highest bit address)
1: Rightmost bit (lowest bit address)
Conversion process
1: 256-to-8 bits (16-word range to byte)
R
m
C
Leftmost bit
n=2 (Start with digit 2.)
R=1 (Convert
2 words.)
FInds leftmost bit
(Highest bit address)
16-to-4 bit decoding
(Location of leftmost bit (m)
is written to R.)
n
0 0 ln
p m
S+1
S1
1
p015