Paul,
Assumming the bit
pattern is a byte and not the lower bit pattern end of an integer then the decimal value is -64.
The bit range of a byte is 2^-7 to 2^7-1 so half of the bit patterns represent negative numbers. The negative values are identified by the first bit starting with 1. To do a binary/Denary conversion:
Subtract the bit pattern from 0.
00000000
- 11000000
--------
Bring the left operand to compliments 2
by flipping the bits and adding 1
00111111
1
--------
01000000
Now add this to the first operand:
00000000
+ 01000000
--------
01000000
the result represents a value of 64
and sign it: -64
Now try it for an integer as an exercise:
say: FFFFFDEA
Convert it to a denary.
Regards
Stephen