FORTH for the PC-G850(V)(S)

[robve]

Currently testing the Forth850 for Forth standard compliance and performance.

The NQUEENS benchmark runs in 0.865 seconds.

This is measured in "fast mode", looping NQUEENS 100 times with a stopwatch.

In "slow mode", the NQUEENS benchmark runs in a little longer in 0.95 seconds.

This is the same Forth NQUEENS program as benchmarked on the PC-E500.

The PC-G850 runs at 8MHz, whereas the PC-E500 runs at 2.3MHz with NQUEENS taking 3.47 seconds. Since 8/2.3 = 3.48, I am happy to see that the performance of these implementations are comparable when adjusting for clock speed. The Z80 runs slightly faster, but that is attributable to the fact the the PC-E500 has a 20 bit address space, which requires 16<->20 bit conversions in Forth when dealing with addresses stored 16 bit Forth cells.

If it matters, the "slow mode" version of Forth850 uses ~300 bytes less of the 8K Forth core, which doesn't seem critical to me to save space. So the "fast" version is probably the best way to go to release once testing is completed.

Both slow and fast versions perform stack over/underflow detection and BREAK key interrupt detection. Without these, NQUEENS would run in 0.84 seconds. But that version won't be as usable to play with since it will crash when the stack over/underflows.

Will release Forth850 soon when testing is completed, so anyone can try it out and rerun the benchmark.

- Rob