## To build: ``` make ``` There is [alternate code](#alternate-code) that is based on the author's notes for DOS/Windows. This cannot be tested by us, not even to compile, but it appears that it should be fine, after the proper header files were added. ### Bugs and (Mis)features: The current status of this entry is: > **STATUS: INABIAF - please DO NOT fix** For more detailed information see [2006/toledo2 in bugs.html](../../bugs.html#2006_toledo2). ## To use: ``` ./toledo2 ``` To end execution press `ctrl-z`. As mentioned in the author's remarks and in the below section, it is supposed to crash on termination though some noted this does not seem to happen in macOS or linux in 2023. ## Try: ``` ./toledo2 ``` and then type in the following: ``` 10 PRINT "HELLO WORLD!" LIST RUN ``` To end the program hit ctrl-z. ## Alternate code: This version, as noted above, should work for DOS/Windows. It uses non-standard functions in place of `read(2)` and `write(2)`, and is based on the author's remarks. ### Alternate build: ``` make alt ``` ### Alternate use: The author noted that for PC/DOS you will have to add `ANSI.SYS` to your `CONFIG.SYS` but this is also something we can't test. Use `toledeo2.alt` as you would `toledo2` above. ## Judges' remarks: We're impressed! Last year, it was a [6502](https://en.wikipedia.org/wiki/MOS_Technology_6502) emulator; this year, it's [8080](https://en.wikipedia.org/wiki/Intel_8080)! It requires an input file (`C`) to be present, but it does not have to be one of `C.BASIC` or `C.BIOS` - you're welcome to write a standalone 8080 program yourself! How about `C.FORTH` or `C.LISP`? In addition to the functionality you could expect from a program of this size, it allows importing files from the host file system (one by one, so you'll have to be patient). Remember the good old days and play (or let your kids play) [Adventure](https://rickadams.org/adventure/) (in the directory `ADVENTUR`); walking in a maze of twisty little passages all alike is easier than understanding the code! **NOTE**: The `KAYPROII.ZIP` file originally came from [http://www.retroarchive.org/cpm/os/KAYPROII.ZIP](http://www.retroarchive.org/cpm/os/KAYPROII.ZIP). For your convenience, we have included `KAYPROII.ZIP` in this entry. Both the `make all` and the `make alt` unzip that file, and the `make clobber` removes those files extracted from the `KAYPROII.ZIP`. ## Author's remarks: This program emulates a complete [Intel(r) 8080](https://en.wikipedia.org/wiki/Intel_8080) processor, along with a teletype and a disk controller, just like at the start of the personal computers revolution (circa 1975). It needs an initial memory image to do something usable, so along with it you will find two files: [C.BASIC](C.BASIC) and [C.BIOS](C.BIOS). Rename [C.BASIC](%%REPO_URL%%/2006/toledo2/C.BASIC) to `C` (NOTE from the judges: running `make` will do this for you), run the emulator, and et voila! you have the public domain Palo Alto [Tiny BASIC](https://en.wikipedia.org/wiki/Tiny_BASIC) (by Li-Chen Wang), published in the very first volume of [Dr. Dobb's Journal](https://en.wikipedia.org/wiki/Dr._Dobb%27s_Journal). Type using uppercase letters. Here are three example programs. Press Enter after each line: ``` 10 PRINT "Hello, world!" LIST RUN 10 FOR A=1 TO 10 20 PRINT A 30 NEXT A LIST RUN 10 INPUT A 20 INPUT B 30 PRINT A+B LIST RUN ``` Press Ctrl+Z to quit. By the way, the segmentation fault is normal at this point. All good programmers started learning [BASIC](https://en.wikipedia.org/wiki/BASIC), now, what about a [CP/M](https://en.wikipedia.org/wiki/CP/M) emulator? Copy `CPM64.COM` to files named `A` and `B` (these will be the disk drives). Now rename the provided `C.BIOS` to `C` and run the emulator. Now you have a running [CP/M](https://en.wikipedia.org/wiki/CP/M) system!, with two files on A: drive, `HALT.COM` to stop the emulator (so it closes drives) and `IMPORT.COM` to introduce new files. The two files are created automatically by the provided C.BIOS. To get a complete [CP/M](https://en.wikipedia.org/wiki/CP/M) system, you will need the following files from the `SOURCE` directory: - `ASM.COM` - `DDT.COM` - `DUMP.COM` - `ED.COM` - `LOAD.COM` - `PIP.COM` - `STAT.COM` - `SUBMIT.COM` - `XSUB.COM` To import them, you must run the emulator with an argument, by example: ``` ./toledo2 DDT.COM ``` When the `>` prompt appears, do: ``` IMPORT DDT.COM ``` When it ends, do `HALT`, so the file is closed, and you can start the same process with another file. At this time I have tested successfully the following software from : - - - Some programs require installation to configure the terminal, locate ANSI or VT-100. ### What is an 8080? It is simply the little brother of the [Z80](https://en.wikipedia.org/wiki/Zilog_Z80); it has no extended registers (`AF'`, `BC'`, `DE'`, `HL'`, `IX` or `IY`), no relative jumps, and no instruction beginning with `CB`, `DD`, `ED` or `FD` exists. The flags are only `S` (Sign, bit 7), `Z` (Zero, bit 6), `P` (Parity, bit 2) and `C` (Carry, bit 0). ### Porting it It is easy if your platform has `getch()`/`kbhit()` and ANSI terminal: - `read` - `Z=kbhit()?getch():0` - `write` - `putchar(7[o])` - `system` - nothing Notice that you'll have to do `#include ` as well. Also add the following to trap Ctrl-C: ``` #include signal(SIGINT, SIG_IGN); ``` **NOTE**: this is what the [alternate code](#alternate-code) is for! **NOTE from the Judges**: in Unix like systems `getch()` is part of curses but this is not what is needed. On PC/DOS you need to add `ANSI.SYS` to `CONFIG.SYS`. In Unix the min 0 on `stty` is required but circa 2001 it was not required. ### NOTICE to those who wish for a greater challenge: **If you want a greater challenge, don't read any further**: just try to understand the program via the source. If you get stuck, come back and read below for additional hints and information. ### How this entry works: The `l` array contains the 64K memory; it is initialized with a boot image loaded from the `C` file. The [program counter](https://en.wikipedia.org/wiki/Program_counter) is the `c` pointer and [registers](https://en.wikipedia.org/wiki/Processor_register) are in `o[]`. The main loop reads every [opcode](https://en.wikipedia.org/wiki/Opcode) and separates them in one of three common forms. A lot of ternary operators selects the instruction. - `o[0]` - B register - `o[1]` - C register - `o[2]` - D register - `o[3]` - E register - `o[4]` - H register - `o[5]` - L register - `o[6]` - Flags - `o[7]` - A or accumulator The following instructions do peripheral operation: - `76` - Quits emulator - `DB 00` - Reads key pressed status - `DB 01` - Reads key - `DB 02` - Reads byte from file (Carry=EOF) - `D3 xx` - Writes byte from acc. to console - `ED ED 02` - Reads sector - `ED ED 03` - Writes sector Memory addresses: - `FBFA` - Low source/target direction - `FBFB` - High source/target direction - `FBFC` - Sector - `FBFD` - Low cylinder - `FBFE` - High cylinder - `FBFF` - Drive. The BIOS is tailor made for this emulator, and helps to simplify it. ### Other notes - The 8080 runs at your computer speed divided between a number that I have not calculated. - This obfuscated processor is created using obfuscated code produced by an obfuscated mind; no brains were harmed during its production, except those that tried to read the code. - The original version of this code was eaten by my C++ dog. - I intended to make it simple to understand; it uses only four C keywords. - Also I discovered that braces are very useful for commenting. - Why bother with prototypes? Every good C programmer can develop their C programs using only one function.