Saturn level 1 vs level 2 instructions

[Christoph Giesselink]

(02-21-2024 03:13 AM)brouhaha Wrote:  Has anyone put together a definitive list of exactly which Saturn instructions were added in "level 1" (1LK7), vs. "level 2" (everything later)?

I had thought that the HP SASM documentation would be a definitive reference, but I've looked at two different versions, and AFAICT they have some have errors and inconsistencies on this matter. The book Customize Your HP-28 by Wlodek Mier-Jedrzejowicz in Appendix D had one of the earliest published descriptions of the 1LK7 extensions, and includes mention of a few instructions that I thought were level 2, and seems to have some confusion over the opcodes.

The SASM documentation references an internal HP engineering document A-1LK7-0005-1 "CPU Hardware Specification". Has a copy of that ever managed to leak out? Or other internal documentation on any of the Saturn chips?

I've been looking at supporting Saturn-based calculators in Nonpareil II, though it's a lower priority than just getting the pre-Saturn models going again. I could just support all level 2 instructions for all models, given that no 71B software should be using level 1 or level 2, and no 18C or 28C code should be using level 2. However, in the interest of simulation accuracy, I'd rather support the correct levels for each model (which implies giving the user a choice between level 0 and level 1 for the 71B).

Also, if anyone has an errata list for the SASM manual, that would be of interest.

Thanks!

The easiest way is using the HP-TOOLS sources. The file /sasm/opcodegen.c contain the information with the definitions LEVEL1, LEVEL2, LEVEL3.

These two ocodes are the difference between the 1LF2 (LEVEL0) and 1LK7 (LEVEL1) CPU:

{"PC=(A)" ,OPD_NONE,LEVEL1,4,"808C","","",0,0,0,0,0,0,0,0,OP_NOTREACHED},
{"RSI" ,OPD_NONE,LEVEL1,5,"80810","","",0,0,0,0,0,0,0,0,OP_NOCHGCARRY},

LEVEL2 instructions are included in all later Saturn CPU designs. Finally LEVEL3 are the additional opcodes of the Saturnator engine introduced with the Apple series calculators.

Another source maybe the emulator sources of Emu28 and/or Emu71/Win. In file FETCH.C the LEVEL2 instructions are disabled for decoding (search for 1LK7).