unix - Homebrew UNIX operating system

Age	Commit message (Collapse)	Author
2019-09-02	Updated Makefile	Jake Mannens

2018-07-14	con_init() is now called during the kernel's boot sequence in kboot()	Jake Mannens
	rather than in kmain() as some subsystems may now require early console I/O. Added 16-bit read/write I/O functions to asm/io.h. These functions are inw() and outw() respectively. Added the file kernel/fs.h which will contain definitions relating to filesystem functions. Defined the type off_t as a signed 32-bit value in sys/types.h. This type will be required for filesystem functionality. Added the directory 'kernel/fs' to the project's source tree. The kernel's makefile has been updated accordingly. This directory will contain any source files relating to filesystem functionality (both assembly and C files). Added the file 'fs/hd.c' to the kernel's source tree. This file currently contains three main functions (which are defined in kernel/hd.h). These functions are as follows; hd_init() to enumerate and initialize the hard disks, hd_read() to read sectors from the disk and hd_write() to write sectors to the disk. Currently, all transfers are done in ATA PIO mode using polling, however this will change in future. The function hd_init() is called during the kernel's boot sequence in kboot(). Added the file hd.img to the project's root directory. This is a 20MB raw image file that will be used by Qemu as a 20MB hard disk. The main makefile has been updated to tell Qemu to use this file on launch.
2018-07-07	Added '-g' flag for GCC to all makefiles to ensure debugging information	Jake Mannens
	is produced. This may change later. Added the new directory 'lib' to the source tree which build lib.a, an archive containing common library routines for both the kernel and userspace code to use. Added the file string.c to the lib directory (as well as the appropriate headers in /include) which provides some basic functions from the standard C string library. Added a physical memory manager which is now located in memory.c. This memory manager tracks free pages from 1MB-8MB with a simple table and allocates memory in blocks of 4KB pages. Multiple pages can be allocated in which they are returned as a linked list. Added a 'page window' in memory.c which allows the temporary mapping of a single page at a time into the current address space. Moved all paging routines that were previously located in page.s over to memory.c where they have been re-implemented as a mixture of C and inline assembly. Moved the primative userspace routines from usrspace.s over to the new sched.c. The only remaining routine, usrcall is now located in asm.s as 'switch_to' which takes two arguments, pointers to the task structure and task state structure of the new task which is being switched to. Pages for userspace are now allocated dynamically. The user binary is loaded in at 1GB upwards. The user stack is located at the end of the 4GB address space with the lower 1GB being reserved for the kernel. Updated the link.ld file for the userspace binary to include the new starting address 0x40000000 (1GB). Renamed the symbols for the user binary blob to make them shorter.
2018-06-16	Initial commit	Jake Mannens