I've packaged the following items:

C source for an 8051 assembler and disassembler. The assembler generates
Intel Hex Format output, and the disassembler reads files in Intel Hex
Format.
Arbitrary Precision Arithmetic library for unsigned integers
including Multiplication, Division, Square Root
Rudimentary Debugger
needs client software at the host in order to be useable.
A stripped-down Multitasking Kernel, with 8051 demo software for:
Serial Communications
client software for a PC host at 57600,N,9,1 available.
Intel Hex download
CRC Check Summing Demo
also needs client software running at the host.
Interrupt Input Processing, for the 8051FA.
Open-loop Stepper Motor Driver
LCD Display/Keypad Input library
Pulse Counting/Data Collection
elaborate multi-tasking control used to concurrently
process the 6 timer-capture interrupts of the 8051FA

Consider this software your development kit. You can use it in your
projects any way you like with no licensing or copyright restrictions. If
you'd like to try your hand at hacking it I encourage you to do so and to
distribute any substantial improvements you may come up in the same spirit
that this is being distributed: free of any restrictions. Everything here is
new and original (as far as I can determine) and was generated over a one
year period 4/91 to 4/92 (except for the assembler) within a total of 300
hours paid development time. The assembler was developed in 7/92.

Send comments and feedback to [email protected]. Direct correspondence
can also be sent to:

Mark Hopkins Consulting
2619 North Oakland Avenue, Suite 204
Milwaukee, Wisconsin 53211-3523
(414)332-8857