vodozhaba / vv4os Goto Github PK

Try to output such a long text so that the terminal gets scrolled.

E.g. \t, \r, etc.

Try running this:

    int* ptr = (int*) 0xFFFFFFF0;
    int val = *ptr;

It won't crash, although corresponding frames aren't mapped.

Try digits(0xFFFFFFFF);

%w means 'word'.

    static inline void PortWrite32(uint16_t port, uint32_t value) {
        __asm volatile("outl %w0, %w1" : : "a" (value), "d" (port));
    }

    static inline uint32_t PortRead32(uint16_t port) {
        uint32_t ret;
        __asm volatile("inl %w1, %w0" : "=a" (ret) : "d" (port));
        return ret;
    }

The boot.asm file aligns bootstrap stack on 4-byte boundaries, but x86 specification requires it to be aligned on 16-byte boundaries!

Try to make a simple handler and register it for IRQ1. It will be called on the first time, but will not on any others. It runs smoothly, however, on IRQ0.

Try to make a simple handler and register it for IRQ1. It will be called on the first time, but will not on any others. It runs smoothly, however, on IRQ0.

Add these features to printf():

• Length specifier
• Floating point output (including hexadecimal)
• Binary output
• Scientific notation
• %n support

The header in io/uart.* files says that the file is called rs232.*

The physical memory manager never allocates the NULL frame, however, it may allocate other frames in the first megabyte, e.g. the framebuffer, which will lead to data corruption and/or unexpected peripheral device behaviour.

x86 virtual memory manager (/arch/x86/mem/virt_mem_mgr_x86.c) simply ignores most errors. Fix it.

/vv4os/io/uart.c:76: PortWrite8(INT_IDENT_AND_FIFO_CTRL, 0xC7); // FIXME: magic number
I copied & pasted that from OSDev wiki without researching. Gotta replace that magic number with logic.

Just try to launch it in Bochs.

Accessing unaligned elements in C is undefined behaviour, better fix that.

Types are called vga_color_scheme and vga_entry, although PascalCase must be used for types in the project.

It happens right after enabling paging.

The virtual memory manager creates the tables in the physical memory, but they don't get identity mapped, which causes page faults if they're accessed after enabling paging.