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README

README - tatOS - July 2016

Welcome to tatOS - "programming for the common man in assembler"

What's new: bezier, bez2pdf,  apps/TCAD update

tatOS is an x86 32 bit hobby operating system that gets worked on in my spare time. 
It has provided many hours of programming enjoyment (perhaps too many !)

The corner stone of tatOS is the "tedit" text editor and the "ttasm" assembler.
The assembler will create 32 bit executables from single source files, and supports 
public and extern symbols and works with "tlink" and "make" to create executables 
from multiple source file projects.

There is a suite of functions for graphics, string handling, file system (/tlib) 
There is a suite of functions to control usb devices. (/usb)

This version of tatOS includes 4 differant usb controller drivers:
* usb 1.0 uhci 
* usb 2.0 ehci with uhci companion controllers
* usb 2.0 ehci with integrated root hub
* usb 2.0 ehci with no usb 1.0 support
You must set USBCONTROLLERTYPE in tatOS.config and reassemble for your hdwre.

This version of tatOS supports these usb devices:
* usb mouse   
* usb keyboard
* usb flash drive

I now use ehci w/root hub exclusively. The Lenovo desktop does not have ps2 ports.
The ps2 keyboard driver and ps2 mouse driver are included for reference only.

Not supported:
* ohci and usb 3.0 xhci usb controllers 
* wireless usb 
* multi-tasking, multi-threading, multiple processors
* APIC, ACPI, EFI, MMX, or SSE. 
See /doc/hardware for a more complete list of supported hardware

tatOS includes a protected mode interface using sysenter/sysexit (see tlib/tlibentry.s)
tatOS includes an elementary identify mapped paging scheme       (see tlib/paging.s)

tatOS is designed for desktop/laptop computers with a single 32bit Intel or 
Amd processor. It will also run on 64 bit multi-processor machines using the 
bootstrap processor only in 32 bit protected mode. 

Most apps and utilities I develop for tatOS use the keyboard only because of time 
constraints, but a few also require the usb mouse.

Video is SVGA graphics mode 0x103 which is 800x600x8bpp, 256 color palletized mode. 
This is the only mode supported.  A tatOS app can draw over the entire 800x600 pixel 
screen with graphic primitives like line, circle, arc, text, rectangle, 
or draw to a private pixel buffer. See functions in /tlib. 
See tlib/video.s for swaping pixel buffers to the screen.

tatOS supports the following file formats: txt & bmp for input and pdf for output.

tatOS can not read or write to your hard drive so dont worry.

tatOS requires a BIOS to boot that supports booting from floppy or flash drive using 
floppy emulation. Use a floppy disc on an old computer or unformatted flash drive with 
a modern computer.  Copy the file "tatOS.img" to the first sector of the device.
Use "dd" on Linux or "rawrite" on Windows.
Linux Floppy Disc: dd if=tatOS.img of=/dev/fd0
Linux Flash Drive: dd if=tatOS.img of=/dev/sda 
I have also had some success booting modern computers with an external floppy drive 
with usb attach. The filesystem on your flash drive will not be preserved but there 
are utilities on Linux or Windows or tatOS to restore this.

If you are able to successfully boot then you will be running a program called the 
tatOS "shell" which gives a scrolling list of utilities you can run. At this point 
you can remove your boot flash drive and install a tatOS FAT16 formatted flash drive 
and go thru the sequence of usb controller init and usb flash drive init (see USB 
Central from the shell). The shell includes a utility to format a flash drive with 
a single partition FAT16 filesystem that is also useable by Linux and Windows. See 
notes in /tatOS/tlib/fat.s about the tatOS FAT16 filesystem restrictions.

Some graphic controls are available.  
See controls.s, list.s, dropdown.s, gets.s in /tlib

There are 3 fonts available which support the ascii character set.  
* font01 is the standard bitmap font. 
* font02 is a smaller bitmap font I use for menus 
* fontHershey is a scaleable vector font.  
See put.s for functions to display ascii characters and strings.

A special memory block called the "dump" (tlib/dump.s) is used by the kernel and your 
apps to write ascii strings (logging) about what is going on.
 
To shut down tatOS just hold down your power button.

If you have added code to /tlib or /usb and nasm reports a TIMES error, 
increase the SIZEOFTLIB in tlib/tatOS.inc and reassemble.

You can break out of most infinite loops or interrupt service routines with 
ctrl+alt+del which sends you back to the shell.

See /doc for more details and help.
See /tlib and /usb source code for all OS function capability.
See /apps for sample applications that can be assembled by ttasm and run 
under tatOS directly from the tedit text editor.

tatOS is written in x86 assembly with NASM and developed on a Debian Linux machine.
Thanks for trying tatOS. 

Tom Timmermann
Janesville, Wisconsin USA


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