Introduction of Computer Science Ch3 & Ch4

# Introduction of Computer Science Ch3 & Ch4 NTNU 計算機概論 ##### [Back to Note Overview](https://reurl.cc/XXeYaE) ##### [Back to Introduction of Computer Science](https://hackmd.io/@sophie8909/SyU5Uuyhr) ###### tags: `NTNU` `CSIE` `必修` `Introduction of Computer Sciencce` # Ch3.Data Storage ## 3-1 Intronduction - Memory cells are arranged by address - MSB (most significant bit) 為最高有效位元 - LSB (least significant bit) 為最低有效位元 - 在電子學看到的MSB LSB就是它們[:arrow_right: ](https://hackmd.io/@sophie8909/r1E_6h2IS) - 8bits = 1 byte ## 3-2 Storing Numbers ### Storing Integers ![](https://i.imgur.com/kNIP2v5.png) | Integer Representation | range | | | --------------------------------- | ---------------------- | --- | | Unsigned representation | 0~(2^n^-1) | | | Sign-and-Magnitude representation | -(2^n-1^-1)~(2^n-1^-1) | | | One's Complement representation | -(2^n-1^-1)~(2^n-1^-1) | | | Two's Complement representation | -(2^n-1^)~(2^n-1^-1) | | ### Excess system - A positive number, called the magic number(bias) , is added to each number to shift them uniformly to the non-negative side. - magic number is normally 【2^m-1^】 or 【2^m-1^-1】 - m is the number of bits used to represent an integer ### Floating-Point Representation #### IEEE 754 standards for floating-point numbers #### Single Precision(單精度) 精度：十進位小數後6位 | Sign | Exponent | Mantissa | | ---- | -------- | -------- | | 1 | 8 | 23 | #### Double Precision(倍精度) 精度：十進位小數後15位 | Sign | Exponent | Mantissa | | ---- | -------- | -------- | | 1 | 11 | 52 | ## 3-3 Storing Text | Codes | | bits | Application | | ------- | -------------------------------------------------- | ---------------------------------------- | ------------------- | | BCD | Binary Coded Decimal | 4(compressed) or 8（zoned） bits | Accounting software | | EBCDIC | Extended Binary Coded Decimal Interchange Code | | | | ASCII-7 | American Standard Code for Information Interchange | 7 bits + 1 bit (parity check) | | | ASCII-8 | American Standard Code for Information Interchange | 8 bits | | | Big-5 | | 16 bits | Chinese characters | | Unicode | | 16 bits | | | ISO | | 32 bits | | ## 3-4 Storing Audio Audio data are transformed to bit patterns through **sampling**, **quantization**, and **coding**. ## 3-5 Storing Images ### Bitmap ### vector ## 3-6 Storing Video # Ch4. Operations on Data ## 4-1 Logical operations logical operation on bits can be unary[^unary] (one input) or binary (two inputs) We interpret 0 as the value flase and 1 as the value true ### Applications：Mask A mask is a bit pattern that is applied to a target bit pattern to achieve a specific result #### NOT invert its input Target 1 0 0 1 1 0 0 0 ------NOT------------------- Result 0 1 1 0 0 1 1 1 #### AND using 0 Force to 0 Target 1 0 0 1 1 0 0 0 AND 0 0 1 1 0 1 0 1 ---------------------- Result 0 0 0 1 0 0 0 0 #### OR Using 1 Force to 1 Target 1 0 0 1 1 0 0 0 OR 0 0 1 1 0 1 0 1 ---------------------- Result 1 0 1 1 1 1 0 1 #### XOR Using 1 Flipping bits Target 1 0 1 0 0 1 1 0 XOR 1 1 1 1 1 0 0 0 ---------------------- Result 0 1 0 1 1 1 1 0 [^unary]:unary 一元運算 ## 4-2 Shift operations (這邊教授 **疑似** 標錯所以當作4-2) ### Logical shift operations ### Arithmetic shift operations(Rotate) ```c= int main () { int a = 10, b = -a ; printf( "a = %d \n" "a >> 1 = %d, a >> 2 = %d\n" "a << 1 = %d, a << 2 = %d\n" "b = %d\n" "b >> 1 = %d, b >> 2 = %d\n" "b << 1 = %d, b << 2 = %d\n" , a , a >> 1 , a >> 2 , a << 1 , a << 2 , b , b >> 1 , b >> 2 , b << 1 , b << 2 ); return 0 ; } ``` {%hackmd @sophie8909/csabb %}