Combining And Splitting Bytes

I have two bytes (8 bits each) I need to combine these into one interger. And then split the top 12 bits into one integer and the bottom 4 bits into another integer.

i.e A = 0xFE
B = 0x03

First step combine two bytes: = 0xFE03
binary - 11111110 00000011

then split -------- ----++++ - = top 12 bits, + bottom 4 bits

then store seperatly

so one integer equals 0000111111100000
and the other equals 0000000000000011


Sorry it is hard to explain, please help.

[deepak_warrier]

Try this module. I haven't tried different inputs, but I think it will work. Reply if it is to your satisfaction or if you have any further problems.

Deepak



Dim b1, b2 as Byte
Dim str as string 'to see the hex number in string format


Dim l1, l2, l3, l4, l5 as Long
'though an integer is 2 bytes long, the maximum digital value
' that can be assigned is approx. 32000, which does not suffice,
' and so we go for the next larger data type, "long"

' &h is used to denote hex numbers
b1 = &HF0
' Hex() converts the number to string format
str = Hex(b1)

'I've included the hex() after every statement to view the results of
' each operation
b2 = &H1A
str = Hex(b2)

l1 = b1
str = Hex(l1)

l2 = b2
str = Hex(l2)

str = Hex(l1)
' to shift 1 bit you multiply by 2
' to shift 4 bits ( 1 nibble) multiply by 2 raised to 4 which is 16
' to shift 1 byte, you multiply by 2 raised to 8 which is 256
l1 = l1 * 256
str = Hex(l1)

l1 = l1 Or l2

str = Hex(l1)
'l3 will give you the lower 4 bits
l3 = l1 And &HF
str = Hex(l3)

'l4 will give you the upper 12 bits
l4 = l1 And &HFFF0
str = Hex(l4)

l4 = CLng(l4 / 16)

str = Hex(l4)

'if you didn't know, "or" is used to set bits to 1
' and "and" is used to set bits to 0 ( resetting)

Your declarations for these variables is wrong:
Dim b1, b2 as Byte
This is proper:
Dim b1 as Byte, b2 as Byte <--- Need to specify type for each variable, otherwise only the last in the line will be the type, the others will be variants.

That's all. (Not to be a tight *** or anything...

Here's the goods:


Sub ByteParse(In1 as Byte, In2 as Byte, Out12 as Integer, Out4 as Integer)
Dim lngBase as Long
Dim Temp1 as Long, Temp2 as Long

Temp1 = In1
Temp2 = In2
lngBase = (Temp1 * 256) Or Temp2 'Combine Bytes
Out12 = (lngBase And 65520) / 16 'First 12 bits
Out4 = lngBase And 15 'Last 4 bits
End Sub




BrewGuru99