FIFTH

-Note: - -Current implementation does not support object oriented programming. -While working on Fifth I got lots of cool new ideas that require reimplementation -of everything. - +

Fifth - virtual machine, operating system, programming language
+
+
+
download latest snapshot +
+ +
This program is free software; you can redistribute it and/or modify it under +the terms of version 3 of the GNU Lesser General Public License or later as +published by the Free Software Foundation. +
+ +
Program author: +
+
Svjatoslav Agejenko +
+
Homepage: http://svjatoslav.eu +
+
Email: mailto://svjatoslav@svjatoslav.eu +
+
+
+ +
other applications hosted at svjatoslav.eu +
+
+ +

+
1 !Project deprecated!
+

+
+Current implementation does not support object oriented +programming. While working on Fifth I got lots of cool new ideas that +require reimplementation of everything. +
+ +

Currently I try to implement those new ideas in the project called - Sixth. - -
-Screenshots - +Sixth +

+ +

+System is built many years ago when I was still using DOS as a primary +operating system. +

2 Introduction

+Fifth is programming lanquage & operating system, running on virtual +CPU, with custom instruction set. It is much like Charles Chunk +Moore's Forth, it also uses stack architecture, and many commands are +similar. Basically I got familiar with concepts of Forth, and being +inspired created my own system. +

+ + + +

+Screenshots +

+ +

Installation

- +

Virtual CPU +
Built-in commands +
Additional commands, realized as loadable modules +
Example Fifth source file - text editor +

3 Installation

Just unpack all files, witout altering original directory structure, -somewhere in your hard disk. For example: C:\MISC\FIFTH\.... -To run fifth you need minimally just 2 files. -emulator itself ( EMULATOR.EXE or EMULATOR.COM ), and -virtual disk file ( DISK.RAW ). -Read more about distribution directory layout. - - - -

Software/Hardware/Human requirements

- - -Software: - MS-DOS 6.22, with HIMEM.SYS loaded. - Mouse driver if you have a mouse. - Does work only when CPU is in real mode. - To recompile ASM sources I used FASM (Flat Assembler). - I ran QBasic utilities on QB 4.5 . - VESA support by BIOS, or external driver (UNIVBE). - -Hardware: - Minimum CPU 386. - 64 KB free RAM below 640KB, - 2 MB of free XMS. - VESA compatible video card. - -Human: - Beginner level Forth knowledge is recommended. - Enthusiasm. - - - -

Numbers representation

- -

- -Fifth uses hexdecimal number representation as primary. -Numbers shape is formed by dividing a square into four parts. -And manipulating their color (black or white). - - - -

Disk file map, and it's data structures

- - -Core and high-level boot code is stored outside of the filesystem to allow -easy access to it, at early booting time, when filesystem is not yet -initialized. - - disk allocation: - -offset length description - -0 ~4 Kb Fifth core -4 Kb ~32Kb high-level boot code -37 Kb ~65Kb FAT -101Kb ~16MB filesystem data area - - FAT entry format: - --2 last sector --1 empty sector -0 -- .. pointer to next block - - file entry format - -offset length description - -0 4 extension -4 16 name -20 4 entry point -24 4 size -28 4 last modification time - - - -

Core architecture

- - +somewhere in your hard disk. For example: C:\MISC\FIFTH\…. To run +fifth you need minimally just 2 files. emulator itself ( EMULATOR.EXE +or EMULATOR.COM ), and virtual disk file ( DISK.RAW ). +

+ +

+Read more about distribution directory layout +

4 Software/Hardware/Human requirements

4.1 Software:

MS-DOS 6.22, with HIMEM.SYS loaded. +
Mouse driver if you have a mouse. +
Does work only when CPU is in real mode. +
To recompile ASM sources I used FASM (Flat Assembler). +
I ran QBasic utilities on QB 4.5 . +
VESA support by BIOS, or external driver (UNIVBE). +

4.2 Hardware:

Minimum CPU 386. +
64 KB free RAM below 640KB, +
2 MB of free XMS. +
VESA compatible video card. +

4.3 Human:

Beginner level Forth knowledge is recommended. +
Lots of enthusiasm. +

5 Numbers representation

+ +

+ +

+Because I can define everything, starting from CPU, why not try also +alternative and unique number representation ? +

+ +

+Fifth uses its hexdecimal number representation as primary. Numbers +shape is formed by dividing a square into four parts. And manipulating +their color (black or white). +

6 Disk file map, and it's data structures

+Core and high-level boot code is stored outside of the filesystem to +allow easy access to it, at early booting time, when filesystem is not +yet initialized. +

6.1 disk allocation

+ + + +++ ++ ++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

offset	length	description
0	~4 Kb	Fifth core
4 Kb	~32Kb	high-level boot code
37 Kb	~65Kb	FAT
101Kb	~16MB	filesystem data area

6.2 FAT entry format:

+ + + +++ ++ + + + + + + + + + + + + + + + + + + + + + + +

code	meaning
-2	last sector
-1	empty sector
0 --	.. pointer to next block

6.3 file entry format

+ + + +++ ++ ++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

offset	length	description
0	4	extension
4	16	name
20	4	entry point
24	4	size
28	4	last modification time

7 Core architecture

Fifth core is simply some amount of already compiled into machine code and linked together modules (entries in other words). In compilation process modules is compiled one by one and simply stored on top of already existing and growing core. Separately from core is kept -dictionary, this is special list that contain names of compiled modules, -variables etc. and they locations in core. Constants use dictionary space -only. Random word can be removed from dictionary at any time. Currently -dictionary can contain at most 1000 entries. - - - dictionary entry format - -offset length description - -0 4 0 < previous entry - 0 = last - -1 = empty -4 15 module name string -19 1 entry type -20 4 entry data - -Core headers as linked list of module names make up something like dictionary. -When some entry address is needed compiler can quickly run through headers -backwards and find needed entry. - - Possible module types - -type description "execute" action - -0 data compile "num" instruction - with address to module -1 submodule compile "call" instruction - with address to module -2 imm. submodule immediately call to module - - - Memory map: (average) - - -0 ~4096 core -1500000 ~32000 highlevel Fifth boot code -200000h core startup messages area -5200000 end of dynamic memory space - - - -

Fifth source format

- - -Fifth uses a different character table and codes than ASCII. -I call it FSCII (Fifth Standard Code for Information Interchange) -for example space character is not 32 but 255 instead. -I plan to use mainly HEX numbers, and create new characters -to represent numeric values. So typical nemric characters "0123..." -is treated like ordinary letters. - - FSCII: - -DEC HEX function - -0 - 15 0 - F HEX numbers -252 FC backspace -253 FD tabulator (TAB) -254 FE carriage return (CR) -255 FF space - -else ordinary characters, like in ASCII. - - - - - -

1 !Project deprecated!

2 Introduction

Installation

3 Installation

Software/Hardware/Human requirements

Numbers representation

Disk file map, and it's data structures

Core architecture

4 Software/Hardware/Human requirements

4.1 Software:

4.2 Hardware:

4.3 Human:

5 Numbers representation

6 Disk file map, and it's data structures

6.1 disk allocation

6.2 FAT entry format:

6.3 file entry format

7 Core architecture

Fifth source format

FIFTH - virtual machine, operating system, programming language

Introduction

Fifth - virtual machine, operating system, programming language

7.1 dictionary entry format

7.2 Possible module types

7.3 Memory map: (average)

8 Fifth source format

8.1 FSCII:

offset	length	description
0	4	0 < previous entry
		0 = last
		-1 = empty
4	15	module name string
19	1	entry type
20	4	entry data

type	description	"execute" action
0	data	compile "num" instruction
		with address to module
1	submodule	compile "call" instruction
		with address to module
2	imm. submodule	immediately call to module

<loc>	<size>	<desc>
0	~4096	core
1500000	~32000	highlevel Fifth boot code
200000h		core startup messages area
5200000		end of dynamic memory space

DEC	HEX	function
0 - 15	0 - F	HEX numbers
252	FC	backspace
253	FD	tabulator (TAB)
254	FE	carriage return (CR)
255	FF	space
else		ordinary characters, same as in ASCII.