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learning catalog
Original, Inverse and Complement
1. Understand storage types
- The data is divided into byte type and font data.
Byte type data occupies 8 bits. Its original code, inverse code, and complement code are all 8 bits, which means that 0-255
font data occupies 16 bits. Its original code and inverse code are 8 bits. Code and complement code are 16 bits, representing 0-65535 - Then some people will have doubts: 8-bit binary and 16-bit binary are both 1, of course it can represent 255 or 65535, but I can represent -127, -32767. Wait a minute, since we say this, then we must figure out what storage method is, is it unsigned storage or signed storage?
- Among the 8 bits, if it is unsigned storage - that is, there is no negative number from 0-255, if it is a signed number, it will occupy a bit by itself, so it is expressed as -127-128.
So we know that our C language int type is also a signed number when it is not written as unsigned. Its range is -2147483648~+2147483647, and the signed number is 4,294,967,295 - So what is the original code storage? When we discuss the original code, we discuss whether it is signed or unsigned