Mermaid JS

Mermaid lets you create diagrams and visualizations using text and code. Read about it from their official website

Integrating mermaid with mdbook

[undone]

State diagrams

"A state diagram is a type of diagram used in computer science and related fields to describe the behavior of systems. State diagrams require that the system described is composed of a finite number of states; sometimes, this is indeed the case, while at other times this is a reasonable abstraction." Wikipedia

Find instructions on drawing state diagrams on this page

• define states (with or without descriptions)(with or without aliases) eg
  1. simple states without descriptions or aliases :

stateDiagram
        start
        running

2. simple states with descriptions

stateDiagram
        start : The bootloader has loaded the kernel image onto the RAM
        running : the kernel runs in Machine mode

3. states with descriptions + aliases

• Define Transitions

    stateDiagram-v2
          s1 --> s2: A transition

• Nested states, sub_modules, notes

    stateDiagram
            s1
            s2
            s3
            [*] --> s1
            s1 --> s2
            s2 --> s3
            s3 --> [*]

            state s3 {
                [*] --> t1
                t1 --> t2
                t2 --> [*]
            }

    stateDiagram-v2
    [*] --> First
    First --> Second
    First --> Third

    state First {
        [*] --> fir
        fir --> [*]
    }
    state Second {
        [*] --> sec
        sec --> [*]
    }
    state Third {
        [*] --> thi
        thi --> [*]
    }

• Choices (if else/ match)
  • define the choice node
  • define th transition conditions

stateDiagram
    load_firmware
    load_bootloader
    load_kernel'
    run_kernel
    shutdown

    state look_for_bootloader <<choice>>
    state look_for_kernel <<choice>>

    [*] --> load_firmware
    load_firmware --> look_for_bootloader
    look_for_bootloader --> load_bootloader : Bootloader is found
    look_for_bootloader --> shutdown : Bootloader is missing

    load_bootloader --> look_for_kernel
    look_for_kernel --> load_kernel : Kernel image is found
    look_for_kernel --> shutdown : Kernel image is Missing

    load_kernel --> run_kernel
    run_kernel --> shutdown

    shutdown --> [*]

• Forks/merges [undone]
• Concurrency [undone]

    graph TD
        A[ Access the Line Status Register] --> B[Access the data_ready status bit];
        B --> C{Is the Data Ready?} ;
        C --> |Yes| D[Read the RHR buffer];
        D --> E[return the read byte];
        C --> |No| E[return None type]

stateDiagram

    [*] --> Program
    state Program{
        [*] --> KeyBoard : Someone presses keyboard Keys
        KeyBoard --> Uart_upper_interface : [stream of bytes]
        Uart_upper_interface --> Uart

        state Uart {
            state if_state <<choice>>
            [*] --> FIFO_Buffer : store byte stream into
            FIFO_Buffer --> if_state : Does FIFO have new Data?
            if_state --> send_interrupt : Yes
            if_state --> [*] : No

            state if_state_2 <<choice>>
            FIFO_Buffer --> if_state_2 : Is all data in FIFO read?
            if_state_2 --> set_uart_as_read_ready : No
            if_state_2 --> set_uart_as_write_ready : yes
            if_state_2 --> stop_sending_read_interrupt : yes
        }

        Uart --> Plic : send interrupt to Plic
        Plic --> CPU  : Plic sends interrupt to CPU
        CPU  --> Trap_Handler : CPU jumps to

        Trap_Handler --> Uart : read the Uart Buffer
        
         


        
    }