osdev

I'm trying to create a bootable floppy drive for my boot.bin and kernel.bin files. My boot.asm code is: bits 16 section .text start: JMP MAIN WAIT_FOR_KEY: MOV AH, 00H INT 16H RET CLEAR: MOV AH, 0H ;CHANGING THE VIDEO MODE TO CLEAR THE SCREEN MOV AL, 03H ;VIDEO MODE COD INT 10H RET LOG_TO_HTS: PUSH BX PUSH AX MOV BX, AX MOV DX, 0 DIV WORD[ALL_SECTORS] ADD DL, 01H MOV CL, DL MOV AX, BX MOV DX, 0 DIV WORD [ALL_SECTORS] MOV DX, 0 DIV WORD[FACES] MOV DH, DL MOV CH, AL POP AX POP BX MOV DL, BYTE [BOOT_DEVICE] RET ECHO: ;-=-=-=PRINTING FUNCTION =-=-=-; LODSB ;MOV ONE CHAR FROM SI TO AL AND DELETE IT

I'm working on a simple kernel and I've been trying to implement a keyboard interrupt handler to get rid of port polling. I've been using QEMU in -kernel mode (to reduce compile time, because generating the iso using grub-mkrescue takes quite some time) and it worked just fine, but when I wanted to switch to -cdrom mode it suddenly started crashing. I had no idea why. Eventually I've realized that when it boots from an iso it also runs a GRUB bootloader before booting the kernel itself. I've figured out GRUB probably switches the processor into protected mode and that causes the problem . the

I have two files which are assembled/compiled/linked into minimalistic kernel. start.s: .set CPACR_EL1_FPEN, 0b11 << 20 .set BOOT_STACK_SIZE, 8 * 1024 .global __boot_stack .global __start .global __halt .bss .align 16 __boot_stack: .fill BOOT_STACK_SIZE .text __start: /* disable FP and SIMD traps */ mov x0, #CPACR_EL1_FPEN msr cpacr_el1, x0 /* set stack */ adr x0, __boot_stack add sp, x0, #BOOT_STACK_SIZE /* call the Rust entry point */ bl __boot __halt: /* halt CPU */ wfi b __halt boot.rs: #[no_mangle] pub extern fn __boot() { unsafe { let ptr = 0x9000000 as *mut u8; *ptr = '!' as u8; } } For

I am writing an OS in Rust and need to directly call into a virtual address that I'm calculating (of type u32 ). I expected this to be relatively simple: let code = virtual_address as (extern "C" fn ()); (code)(); However, this complains that the cast is non-primitive. It suggests I use the From trait, but I don't see how this could help (although I am relatively new to Rust and so could be missing something). error[E0605]: non-primitive cast: `u32` as `extern "C" fn()` --> src/main.rs:3:16 | 3 | let code = virtual_address as (extern "C" fn ()); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = note

I want to boot a custom kernel (non-multiboot) with GRUB2, I've read that I need grub.cfg like this: menuentry "custom kernel" { set root=(hd0,0) chainloader +1 } So, I have some questions: How grub detect kernel? (with multiboot spec I used kernel /boot/kernel.bin ) How my kernel must look like (sorry for my bad english)? Must it be 512 bytes at all (like custom bootloader, which loaded into 0x7c00)? (hd0,0) is hard drive partition and what I must put if I use CD? Maybe (cdrom0,0) ? To boot Linux kernel we can use linux command, can I use it to boot my custom kernel (with some changes)? Will

There are a lot of question on stackoverflow with the similar title. I read all of them, but none of them answers my problem. This is why I opened this question. I am creating an operating system in assembler and C. I found that I must compile C code to binary format, extract text section and save it as a file, then convert it to ISO, then mount it to virtual optical dive of diskete and then load my OS in VirtualBox. So, that is a lot of work I want to avoid. I don't want to convert my binary file to ISO every time. So, I decided to put the binary machine code of my OS to virtual hard drive (