Denso BHT-BASIC 100 SERIES, Руководство программиста

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Chapter 15. Function Reference
340
Syntax:
BCC$(datablock,checktype)
Parameter:
datablock
A string expression.
checktype
A numeric expression which returns a value from 0 to 2.
Description:
BCC$ calculates a block check character (BCC) of datablock according to the
block checking method specified by checktype , and returns the BCC.
• checktype is 0, 1, or 2 which specifies SUM, XOR, or CRC-16, respectively, as
described below.
*
The upper byte and the lower byte of the operation result will be set to the 1st and 2nd characters,
respectively.
• A common use for BCC$ is to perform block checking or to generate a BCC for a
data block.
Block Check Character String function
BCC$
Returns a block check character (BCC) of a data block.
checktype
Block check-
ing method No. of charas
for BCC
BCC
Generative
polynomial
0
SUM 1 Lowest one byte of the
sum of all character
codes contained in a
datablock .
1
XOR 1 One byte gained by
XORing all character
codes contained in a
datablock .
2
CRC-16 2* Two bytes gained from
the cyclic redundancy
check operation
applied to bit series of
all characters in
dat-
ablock with the bit
order in each byte
inverted.
X
16
+X
15
+X
2
+1