2 Instructions
2-156
CP1E CPU Unit Instructions Reference Manual(W483)
--B/--BL
Applicable Program Areas
Operands
Operand Specifications
Flags
Function
Instruction Mnemonic Variations
Function
code
Function
DECREMENT BCD --B @--B 596
Decrements the 4-digit BCD content of the speci-
fied word by 1.
DOUBLE DECREMENT BCD --BL @--BL 597
Decrements the 8-digit BCD content of the speci-
fied words by 1.
Symbol
--B --BL
Area Step program areas Subroutines Interrupt tasks
Usage OK OK OK
Operand Description
Data type Size
-- --L -- --L
Wd
--B: Word
--BL: First word
WORD DWORD 1 2
Area
Word addresses Indirect DM addresses
Constants CF
Pulse
bits
TR
bits
CIO WR HR AR T C DM @DM *DM
Wd OK OK OK OK OK OK OK OK OK --- --- --- ---
Name Label Operation
Error Flag P_ER • ON if the content of Wd/Wd+1 and Wd is not BCD.
• OFF in all other cases.
Equals Flag P_EQ • ON if the result is 0000/0000 0000 after execution.
• OFF in all other cases.
Carry Flag P_CY • ON if a digit in Wd/Wd+1 or Wd went from 0 to 9 during execution.
• OFF in all other cases.
--B
The --B(596) instruction subtracts 1 from the BCD
content of Wd. The specified word will be decre-
mented by 1 every cycle as long as the execution
condition of --B(596) is ON. When the up-differenti-
ated variation of this instruction (@--B(596)) is used,
the specified word is decremented only when the exe-
cution condition has gone from OFF to ON.
--BL
The --BL(597) instruction subtracts 1 from the 8-digit
BCD content of Wd+1 and Wd. The content of the
specified words will be decremented by 1 every cycle
as long as the execution condition of --BL(597) is ON.
When the up-differentiated variation of this instruction
(@--BL(597)) is used, the content of the specified
words is decremented only when the execution condi-
tion has gone from OFF to ON.
Wd: Word
--B(596)
Wd
Wd: First word
--BL(597)
Wd
-1
Wd Wd
WdWd+1 Wd+1 Wd
-1
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