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@@ -1,125 +0,0 @@ -* vi: ft=markdown - -Welcome to FoolOS - -================= -Copyright M.Idziorek 2014 <m.i@gmx.at> - -Disclaimer ----------- - -This is a simple and useless "operating system", with very basic -features, sorry. It is the fruit of my fundamental explorations of -the 32-bit protected mode, interrupt handling, memory management and -some other things. - -[] - - -NOTES -===== - -cli; disable interrupts -lgdt -lidt -sti; enable interrupts - -Linux Startup x86 -================= - -1. arch/x86/boot/header.S - -Contains the header and linux 16 bit code. - -This code should be entered with a bootloader at the address specified -within the header (as _start) which will put us at 'start_of_setup' - -Direct loading will put us at 'start2' at the very start which will -show an error message - -If everyhing goes right we will enter the 16-bit real mode C module -with: - -call main ; should not return - -2. arch/x86/boot/main.c - -void main(void) will do some checks and detections (cpu,mem,..) and -invoke: go_to_protected_mode(); - -3. arch/x86/boot/pm.c - -go_to_protected_mode() - will disable interrupts and set up the initial -idt and gdt descriptor tables before calling: protected_mode_jump() and -passing the address of code32_start. - -4. arch/x86/boot/pmjump.S - -back in assembly-world the actual transition is made inside -'protected_mode_jump' and we move on to 'in_pm32' where the data segment -is set up and we jmpl to the 32-bit entry point of the kernel. - -5. arch/x86/kernel/head32.c (assumption!?) - -void i386_start_kernel(void) - -6. init/main.c - -start_kernel(void) - -setup_arch()!! - -Interrupts -========== - -arch/x86/include/asm/irq_vectors.h each entry is 8 bytes - -ISA interrupts: - -0x30 0x0000 0x0000 0x0000 0x0000 -0x31 -0x32 -.. -0x3f - - -TODOS -===== - * study LINUX KERNEL - * GNU HURD - * MINIX - * FreeBSD etc. - -NETWORK -======= - - look at following linux drivers: - * e1000 - -notes -===== - -* posix - minimal set of function calls! -* distributed os -* caches L1,L2,L3 -* controller -> ide inteface of device -* probe memory! -* a20~ wrap - -* ssd card reader -* cobol fortran algol? compilers? - -* quotation: ontogeny nrecapitulates phylogeny - -* own simple sell - -check: -apertium? -clang -freebsd -user-mode-linux - -REFERENCES -========== - -http://www.brokenthorn.com/Resources/OSDev17.html |