Computer Hardware User Manual

211
The 4 possible C values and the conversions that they produce are shown be-
low. (In S, 0 indicates the rightmost byte and 1 indicates the leftmost byte.)
0
1
R to R+15
R+16 to R+31
S
C: 1000
0
1
R to R+15
R+16 to R+31
S
C: 1010
0
1
R to R+15
R+16 to R+31
S
C: 1011
0
1
R to R+15
R+16 to R+31
S
C: 1001
The following is an example of a one-byte decode operation from the rightmost
byte of S (C would be 1000 in this case).
. . .
R
Bit
15
Bit
00
000000
. . .
R+1
Bit
15
Bit
00
000000
R+2
Bit
15
Bit
00
000000000100000 0
. . . . . .
R+15
Bit
15
Bit
00
000000
Source word
2
Bit 2C (i.e., bit number 12 in
the third word) turned ON.
C
Flags ER: Undefined control word.
The result words are not all in the same data area.
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