On Wed, Jul 18, 2018 at 5:37 PM, Dibyendu Majumdar <mobile(a)majumdar.org.uk> wrote: ​I'm not sure if this is the last. This is a pointer to the V7 Ritchie Compiler: https://minnie.tuhs.org//cgi-bin/utree.pl?file=V7/usr/src/cmd/c - The sources and the makefile build the three passes /lib/c[012] This should be a good starting point/base line. Be careful because the Johnson Compiler (pcc) was also included with V7 and is a different technology. This is important because their are modifications to both the Ritchie and Johnson compilers 'in-the-wild' for other back-ends and new optimizations. I for instance, re-targeted the Ritchie compiler to what would become the 68000 (it was not yet numbered, it was an experimental chip when we had access to it in the late 1970s in Tek Labs - mine was a 16 bit 'int' as I was coming primarily from the PDP-11 at the time and the chip was a 16 bit chip internally - so the code was tight and clean and I basically substituted PDP-11 instruction sequences for 68000 sequences). IIRC, Jack Test's 68000 compiler from MIT which was about 18 mons later was based on the Johnson compiler but he used a 32 bit 'int' which proved easier for porting programs from the Vax, as the chip supported 32 bit words even though it took 2 ticks to do anything [so Jack's compiler generated slower code for many simple ops]. I recommend, that google for the old USENIX tapes and see what you turn up and compare. ᐧ

On 19 July 2018 at 15:50, Clem Cole <clemc(a)ccc.com> wrote: Many thanks - I will compare this with https://github.com/eunuchs/unix-archive/tree/master/PDP-11/Trees/V7/usr/src… which is what I have been looking at. I guess that by this time the work had transitioned to pcc so probably there isn't a later version available? Yes understood. Thank you for the info - I will certainly look at the USENIX tapes. I will try to port the C compiler to amd64 - while preserving as much of the original code as I can. But not sure if this is even feasible. Thanks and Regards Dibyendu