Machine language
Assembly language
High-level languages: fortran, basic, pascal, c
Translation: The process of translating high-level language into machine language
Compile program
Interpreter
Computer architecture
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Computer system organization: the attributes of the computer system seen by programmers
Refers to the attributes of traditional machines seen by programmers who use the machine, assembly language programming: instruction set, data type, memory addressing technology, I/O mechanism -
Computer composition: Refers to how to realize the computer architecture. How to fetch instructions, analyze instructions, fetch operands, and perform operations. The instructions are the same, it can only be considered that they have the same structure, and how to start the line instruction may be completely different (multiplication circuit may be used to realize multiplication instructions, or continuous addition circuit may be used)
The hardware structure of the computer system
Composition: CPU (computing unit, controller), I/O device, main memory, system bus.
Controller (Control Unit, CU): Interpret the instructions in the memory and issue various operating commands to execute the instructions.
Arithmetic logic unit (ALU): complete arithmetic logic operations.
System bus
- Data Bus
- Address bus
- Control bus
Bus performance index
- Bus width: number of buses
CPU
Computer method
The information is all codes composed of 0 and 1 internally.
Unsigned and signed
Unsigned number
Each bit in the register can store a value,
When storing the number of symbols, leave a place to store the symbols.
When the machine word length is the same, the value range is different.
Signed number
Machine number truth value
0 positive
1 negative
Put in front of significant numbers
Source code notation
The value bit is the absolute value of the true value
Two's complement notation
Find a positive number equivalent to a negative number to replace the negative number
Mod
Complement
-3 +9 mod 12 +9 is the complement of -3 modulo 12
- The positive complement of a negative number is: modulus + negative number itself
- The sum of absolute values is modulo
- The complement of a positive number is itself
+1010 complement 0,1010
-1101 complement 1,0011
In addition to the sign bit of the source code, each bit is negated, and the last bit is increased by 1
One's complement
Features
- The highest bit of the three machine numbers is the sign number. Use "." (decimal number)"," (positive number) between sign and value
- When the true value is +, the original code, complement code, and inverse code have the same form
- When it is -, the inverse code is the original code "negation of each bit", and the complement code is the original code "negation +1"
Fixed-point and floating-point representations of numbers
Fixed-point representation
A number with the decimal point fixed at a certain position
Pure decimal
Pure integer
Floating point representation
mantissa
Order code
Base: 2, 4, 6
Specifies that the mantissa of a floating-point number is in pure decimal form, and the floating-point number with the highest digit of the mantissa is 1 becomes a normalized number
0.000011
0.11
