As the name implies, P2 is the second version of the Portable Pascal compiler. It seems to be the first one widely distributed and also the first one to have surviving sources.
One of the distributions of P2 went to California, UCSD. And that version evolved into the UCSD Pascal system.
Mark Rustad took the P2 source, stripped it (no reals e.g.) and changed the p-code to a compact bytecode in Pascal-M.
(********************************************************* * * * * * STEP-WISE DEVELOPMENT OF A PASCAL COMPILER * * ****************************************** * * * * * * STEP 5: SYNTAX ANALYSIS INCLUDING ERROR * * HANDLING; CHECKS BASED ON DECLARA- * * 10/7/73 TIONS; ADDRESS AND CODE GENERATION * * FOR A HYPOTHETICAL STACK COMPUTER * * * * * * AUTHOR: URS AMMANN * * FACHGRUPPE COMPUTERWISSENSCHAFTEN * * EIDG. TECHNISCHE HOCHSCHULE * * CH-8006 ZUERICH * * * * * * * * MODIFICATION OF STEP 5 OF PASCAL COMPILER * * ***************************************** * * * * THE COMPILER IS NOW WRITTEN IN A SUBSET OF * * STANDARD PASCAL - AS DEFINED IN THE NEW * * MANUAL BY K. JENSEN AND N. WIRTH - AND IT * * PROCESSES EXACTLY THIS SUBSET. * * * * AUTHOR OF CHANGES: KESAV NORI * * COMPUTER GROUP * * T.I.F.R. * * HOMI BHABHA ROAD * * BOMBAY - 400005 * * INDIA * * * * THESE CHANGES WERE COMPLETED AT ETH, ZURICH * * ON 20/5/74. * * * * * *********************************************************)