#8086 Emulator Code As Supplied

8072A 3.5' floppy disk controller (1.44MB/720KB) It manages to implement most of the hardware in a 1980вЂ™s eraIBM-PC using a few hundred fewer bits than the total number ofTransistors used to implement the original 8086 CPU.If you are using OS X, the included sc-ioccc.terminal configuration file willCorrectly display console applications that use ANSI graphics.Update: This entry now has its own web page AuthorвЂ™s comments: A tiny but highly functional PC emulator/virtual machineThe author hereby presents, for the delectation (?) of the judges, a portable PC emulator/VM written specifically for the IOCCC which runs DOS, Windows 3.0, Excel, MS Flight Simulator, AutoCAD, Lotus 1-2-3 вЂ¦In just 4043 bytes of C source, you get a complete mid-late 1980s-era IBM-compatible PC, consisting of: /cable3 bios-image-file floppy-image-file This entry weighs in at a magical 4043 bytes (8086 nibbles, 28,301Bits). The current emulation mode is briefly displayed on the Floppy Emus title screen on the display, whenever the device is powered-on or reset.Adrian Judges' comments: To build: make cable3To run. With this, it allows the programming of assembly language, reverse engineering, hardware architecture, and creating miniature operating system (OS).The Mac/Lisa firmware has emulation modes for a Macintosh 3.5 inch drive, Lisa 3.5 inch drive, or HD20-type Macintosh hard drive.

For everyone else, please run the emulator on a little endian machine. 8042 keyboard controller with 83-key XT-style keyboardThe emulator uses the SDL graphics library for portability, and compiles for Windows, Mac OS X, Linux and probably most other 32-bit/64-bit systems too.If you like living on the edge you can try building the emulator on a big endian machine, and you will get an emulation of a big endian 8086, a rather bizarre and somewhat useless beast. 8259 programmable interrupt controller (PIC) Hercules graphics card with 720x348 2-color graphics (64KB video RAM), and CGA 80x25 16-color text mode support

However Windows has no stty. You will need to adjust the Makefile if your system lacks sdl-config to correctly point to the SDL libraries and header files.On UNIX-based systems we can get raw keystrokes using stty. I have received reports that the emulator works on Raspberry Pi/Android/ARM (you will need to compile with -fsigned-char) and iOS. The Makefile supplied is good for Mac OS X, Linux and probably other UNIXes. This entry might result in an adjustment to the IOCCC size tool for the 2014 competition (see above).This entry has been tested on Windows (compiled with MS Visual Studio 20), Mac OS X (clang and gcc), and Linux (clang and gcc). This entry highlights the importance of comments in C.

8086 Emulator Code As Supplied

Therefore the emulator is best run from a shell script that looks something like: stty cbreak raw -echo min 0The simplest use of the emulator is with a single floppy boot disk image, like the fd.img provided, which is a FreeDOS boot disk.Before running the emulator on a Unix-type system, stty needs to be used to put the keyboard into raw mode (and afterwards it needs to be put back to cooked). /cable3 bios-image-file floppy-image-file PLEASE NOTE that under UNIXes the keyboard must be in raw mode for the emulator to work properly. 32-bit Mac OS X, which uses 64-bit file offsets) this is not the case, and to run successfully on these systems, you will need to explicitly declare these functions by adding the appropriate include to the top of the source: #include Usage. For example, for Windows/MS Visual Studio, instead of the Makefile definition of KB, use something slightly different - add the following entry to the Preprocessor Definitions list in the Project Properties page: KB=(kb=H(8),kbhit())&(r=getch(),H(7))The code as supplied uses implicit function declarations for POSIX file I/O and in doing so assumes that file offsets are the same bit width as your architecture.

Rather than make the emulator less portable and use ioctl or platform-dependent equivalents to obtain real scan codes from the keyboard, the emulator BIOS does the reverse of a real PC BIOS and converts ASCII characters to scancodes, simulating press/release of the modifier keys (e.g. This is harder than it sounds because a real 8042 returns scan codes rather than the ASCII characters which the C standard I/O functions return. Keyboard emulationThe emulator simulates an XT-style keyboard controlled by an Intel 8042 chip on I/O port 0x60, generating IRQ1 and then interrupt 9 on each keypress. Or, you can install programs from regular floppy disk images (see вЂњFloppy disk supportвЂќ below). OSFMount, on a Mac using hdiutil, or on Linux using mount, providing an easy way to copy files and programs to and from the disk image.

For example, to get the F4 key, press Ctrl+F then 4. International keyboards).Most of the time you can just type normally, but there are special sequences to get Alt+xxx and Fxxx.To send an Alt+XXX key combination, press Ctrl+A then the key, so for example to type Alt+F, press Ctrl+A then F.To send an Fxx key, press Ctrl+F then a number key. The OS (DOS/Windows) then converts them back to ASCII characters and normally this process works seamlessly (although donвЂ™t be surprised if there are issues, for example, with non-QWERTY e.g.

Direct video memory accesses for the 80x25 CGA color text mode are converted to ANSI terminal escape sequences. Text mode supportThe emulator supports both text output via the standard BIOS interrupt 0x10 interface, and also direct video memory access (one page, 4KB video RAM at segment B800) in 80x25 CGA 16-color text mode.BIOS text output calls are converted to simple writes to stdout. Other key combinations are left for the discovery of the user. To send a Page Up key, press Ctrl+F then E.

Graphics mode supportHercules 720x348 monochrome graphics mode emulation is implemented using SDL. If this happens, just use the DOS CLS command to clear the screen and all will be well again. On Mac OS X there is a freeware font called Perfect DOS VGA 437 which does the trick).Occasionally a DOS application on exit will leave the video hardware in an odd state which confuses the emulator, resulting in subsequent text output being invisible. You might want to set the font in your terminal program to something that includes these (e.g. You are compiling the emulator with MS VC++ and running in a Windows console window) then PC applications that directly write to video memory in text mode may be unusable.Most CGA I/O ports are not supported except for the CGA refresh register at 0x3DA, which some applications use for timing or synchronisation.The regular PC character code page (437) includes various extended ASCII characters for things like line drawing.

The emulator simulates this configuration, too, using separate windows for the (terminal) text and (SDL) graphics displays. AutoCAD) support a PC configuration with a CGA card and a Hercules card, for simultaneous text and graphics output on different displays. Dual graphics card supportSome applications (e.g. Including code to redirect keystrokes from the SDL window to the main terminal window would have busted the IOCCC size limits, so you need to keep the main emulator terminal window in focus at all times even when you are doing graphics (sounds a little odd but you will get used to it).On UNIXes, SDL will automatically output graphics via X11 if the DISPLAY environment variable is set up. CGA graphics modes are not supported.When an application enters graphics mode, the emulator will open an SDL window (which will be closed when the application goes back to text mode).

8086 Emulator For Mac