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Altera_Forum's avatar
Altera_Forum
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11 years ago

Simple Signed Adder is complex to understand

Hi guys, still asking beginner questions, sorry. I have this code and cant figure out what the '0' in ('0' & cin) is doing. This is what I think: Lets say we we need to do add two to negative four...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
11 years ago

Well I'm learning VHDL by my self and the only resources I have are books, forums and internet. I have to admit its not easy this way but I practice a lot to better understand how every thing works. Also thanks for this suggestion. I'll see how it performs. One more question if I may, when declaring something 'signed', the MSB always indicates the sign bit when code is compiled? So lets say that A is signed with a value 1100, will the compiler know that it means -4? I mean, how are std_logic_vector, unsigned, signed and integer synthesized?