the only difference between signed and unsigned is the
interpretation of the
Most
Significant
Bit.
with unsigned, it is
plus MSB-Value, with signed it is
minus MSB-Value.
for type word this means, either +32768 or -32768.
when you recieve a value, it has several bits set or not, but it will be the same, no matter if you interprete it signed or unsigned.
every unsigned value can loslessly be put into a signed variable, because they are just the same, only the interpretation differs.
Code: Select all
a.w = %1001010110101101
b.l = %1001010110101101
Debug a
Debug b
c.w = -27219
d.w = 38317
Debug Bin(c,#PB_Word)
Debug Bin(d,#PB_Word)
when you want to recieve an unsigned Long, just recieve a Long, it will be the correct value.
only when you want to
display it, you'll need to display the MSB as positive value not as negative,
so you should use a bigger container, quad in this case, to make it a value-bit and no longer the sign-bit.
when transferring the value, use the bit operator
& to make sure this will happen.
Code: Select all
a.l = %10010101101011011001010110101101
Debug a
Debug Bin( a, #PB_Long )
b.q = a & $FFFFFFFF
Debug b
Debug Right( Bin( b, #PB_Quad ), 32 )
you can put the &-Operation into a Macro, if you want it to look like a function.
Code: Select all
Macro LongToULong( _LVal_ )
( ( _LVal_ ) & $FFFFFFFF )
EndMacro
some uLongToLong is just not needed, as you saw above, you can just put the unsigned value into the signed variable, the bits will be set correctly.
you can see this when you e.g. try to assign 260 to a Byte:
the parser will tell you that a Byte has to be -128 to 255,
that means,
both signed or unsigned can be assigned without problems.
