npd

npd is a simple disassembler for the HP Nanoprocessor.

Example

Disassemble a binary file rom.bin by typing ./npd rom.bin .

A listing file rom.lst will be created:

                ;----------------------------------------
                ; npd v1.0 - Nanoprocessor Disassembler
                ; File: ./rom.bin
                ; Size: 14 Bytes
                ; Date: 2023-07-20   17:43
                ; Mode: Octal
                ;----------------------------------------
                L_0000
0000:  145                LDA  R5         ; Load ACC from Register
0001:  003                DED             ; Decrement ACC (BCD)
0002:  017                SAN             ; Skip on ACC != 0
                ;-------------
0003:  200 013            JMP  L_0013     ; Unconditional Jump
                ;--------------------------
0005:  165                STA  R5         ; Store ACC at Register
0006:  146                LDA  R6         ; Load ACC from Register
0007:  002                IND             ; Increment ACC (BCD)
0010:  166                STA  R6         ; Store ACC at Register
0011:  200 000            JMP  L_0000     ; Unconditional Jump
                ;--------------------------
                L_0013
0013:  146                LDA  R6         ; Load ACC from Register
0014:  002                IND             ; Increment ACC (BCD)
0015:  166                STA  R6         ; Store ACC at Register

                          END

Motivation

I started this project to help understand the workings of some vintage HP equipments that uses the Nanoprocessor like the old HP 4262A LCR meter.

Requirements

As the source code is very simple the only requirement is a modern C++ compiler. No external library is necessary.

I compiled it in Linux using g++ version 11.3.0 and GNU Make version 4.3 but it shall be easy to compile in other operating systems as well using other C++ compiler. Just read the compiler of choice documentation.

Compiling

At the terminal prompt in the project root directory type:

	g++ -O2 -s -std=c++11 ./src/*.cpp -o npd

Alternativelly, if you have make installed, type:

	make

An executable file named npd shall be created in the same directory.

Usage

npd is a command line application. It runs on a terminal.

To disassemble a binary file run npd followed by it's name. For example, to disassemble the file rom.bin type:

	./npd rom.bin

It will create a listing file named rom.lst.

By default the output file includes addresses and opcodes. To get a clean rom.asm file use the -a option:

	./npd -a rom.bin

By default all addresses, opcodes, and parameters will be in octal base as the original processor documentation. If you prefer hexadecimals use option -x .

Command line options

These are the available npd command line options:

option	effect
`-h`	Output a help text and exit
`-v`	Output version and license information and exit
`-o OUTFILE`	Set output file name
`-f`	Overwrite existing output file without warning
`-a`	`.asm` output file (no addresses or opcodes)
`-x`	Hexadecimal numbers (default is octal).
`-c`	Asterisk comment character (default is `;`).

References

To learn about the HP Nanoprocessor check these great resources:

CPU Schack Museum: "The Forgotten Ones: HP Nanoprocessor".
CPU Schack Museum: "HP NanoProcessor Mask Set".
Ken Shirriff's blog: "Inside the HP Nanoprocessor: a high-speed processor that can't even add". Here you can find a link to the Nanoprocessor user's guide.
Ken Shirriff's blog: "HP Nanoprocessor part II: Reverse-engineering the circuits from the masks".

License

License GPLv3+: GNU GPL version 3 or later. This program comes with ABSOLUTELY NO WARRANTY. This is free software, and you are welcome to redistribute it under certain conditions; see file Copyright.txt for details or visit https://gnu.org/licenses/gpl.html.

ricaflops/npd

npd