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Conversion Instructions Section 3-11
Description BCDS(471) converts signed binary data to signed BCD data. First the signed
binary data in word S is checked to verify that it is within the valid range for the
signed BCD format specified in the control word (C). If the source data is cor-
rect, the signed binary data in S is converted to signed BCD and output to D.
If the source data is incorrect, the Error Flag will be turned ON and the
instruction will not be executed.
Note (1) Values of –0 in the source data will be treated as 0 and will not cause an
error.
(2) Some Special I/O Units require signed BCD data inputs. BCDS(471) can
be used to convert signed binary data for output to these Units.
The control word specifies the signed BCD format that will be used for the
result, as shown below.
C = 0000 (Output Data Range: –999 to 999 BCD)
C = 0001 (Output Data Range: –7999 to 7999 BCD)
C = 0002 (Output Data Range: –999 to 9999 BCD)
Index Registers ---
Indirect addressing
using Index Registers
,IR0 to ,IR15
–2048 to +2047 ,IR0 to 1–2048 to +2047 ,IR5
DR0 to DR15, IR0 to IR15
,IR0+(++) to ,IR15+(++)
,–(– –)IR0 to, –(– –)IR15
Area C S D
Signed BCD
Signed binary
Signed BCD format
specified in C
3 digits BCD, 12 bits
Sign bit (0: Positive; 1: Negative)
Status of 3 bits: 0
3 digits BCD, 12 bits
3 bits of digit 4 (0 to 7)
Sign bit (0: Positive; 1: Negative)
3 digits BCD, 12 bits
0 to 9: Fourth digit BCD
F: Negative (–)
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