81 lines
2.3 KiB
Markdown
81 lines
2.3 KiB
Markdown
up:: [[Logique séquentielle]]
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#s/informatique #s/maths/logique
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# ALU binary operators
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| bin | operator |
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| ---:|:---------- |
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| 000 | COMParison |
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| 001 | zero |
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| 010 | OR |
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| 011 | AND |
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| 100 | ADD (+) |
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| 101 | SUB (-) |
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| 110 | COPY A |
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| 111 | COPY B |
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# How to operate
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## op exec
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`op exec` is the component that gathers the ALU and the data registers. It can :
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- perform operations with the ALU
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- read data : register to ALU inputs
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- write data : ALU output to registers
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- take input : 8 bit bus to ALU inputs
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- give output : ALU output or registers to 8 bit bus
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> [!info] Writing data to a register
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> It is not possible to write data directly from the 8 bit bus to the registers.
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> If you want to register some data, you have to do the following :
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> - write the data to the ALU inputs (input A for example)
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> - set the ALU operation to copy (copy A in our example, that is `110`)
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> - write from the alu to the register (give the register address in the 8 bit bus, and set the `from ALU` and `to register` bits)
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# Binary code
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The binary code of the CPU. They are stored in 2 octets.
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| binary code | action |
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| ----------------------:| --------------- |
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| `0000 0000 0000 0000` | NOOP |
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| SET ALU OPERATIONS | |
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| `XXX0 0000 0000 0001` | set X as ALU op |
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| `0000 0000 0000 0001` | COMParison |
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| `0001 0000 0000 0001` | ZERO |
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| `0010 0000 0000 0001` | OR |
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| `0011 0000 0000 0001` | AND |
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| `0100 0000 0000 0001` | A+B |
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| `0101 0000 0000 0001` | A-B |
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| `0110 0000 0000 0001` | BYPASS A |
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| `0111 0000 0000 0001` | BYPASS B |
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| READ / WRITE | |
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| `XXXX XXXX 0000 0010` | X --> ALU A |
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| `XXXX XXXX 0000 0011` | X --> ALU B |
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| `XXXX XXXX 0000 0110` | reg X --> ALU A |
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| `XXXX XXXX 0000 0111` | reg X --> ALU B |
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| `0000 0000 0000 1000` | ALU --> reg |
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![[digital logic sim computer 2023-07-18 09.57.52.excalidraw]]
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| bin | operator |
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| ---:|:---------- |
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| 000 | COMParison |
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| 001 | zero |
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| 010 | OR |
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| 011 | AND |
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| 100 | ADD (+) |
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| 101 | SUB (-) |
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| 110 | COPY A |
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| 111 | COPY B |
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write 10 to A -> 0001010 00000100
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write 11 to B -> 0001011 00001000
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write 100 to op 00000100 00010000
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