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Learning POWER9 assembly

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vmlinuz:
Can anyone recommend some good resources for someone who wants to get into POWER9 assembly programming? I have an old book somewhere about 32-bit PowerPC assembly but don't know how much things have changed since the days of the Power Macintosh G4.

ClassicHasClass:
32-bit assembly is a start but it will only get you part of the way -- you should really start with 64-bit and just think in those terms. Fortunately PowerPC was very forward looking from the beginning and 64-bit instructions were specified even from the days of the 601: my best reference for Power ISA is a very old book called Optimizing PowerPC Code by Gary Kacmarcik, supplementing it with the Power ISA 3.0b documentation and the ppc64le ELF v2 ABI specification. I have a physical copy of OPPCC but there are PDF copies around.

mparnaudeau:
I also have the physical book Optimizing PowerPC Code that I also recommend to be more familiar with the PowerPC instruction set in general, what is described by category (load-store, integer, FP, branches ...). The book also explains well stack frames and lists instructions with one described per pagen what includes PPC64 instructions, as this clean architecture came with 32-bit and 64-bit very early. The part on optimization is good but rather short and it may not match current POWER architecture on some points.

Another good resource I remember is "Ensamblador del PowerPC con Mac OS X". Even if it is in spanish, this document is more oriented as a tutorial.

Searching "powerpc asm tutorial" also reports good resources from IBM but not only.

vmlinuz:
I did some reading of the recommended materials thus far. How in the actual hell is this considered a Reduced Instruction Set?!?!? PowerPC from almost 30 years ago makes the z/Architecture look like a paragon of simplicity and elegance - God only knows what abominations await in POWER9.

Update:



Are you f**king kidding me

ClassicHasClass:
No, actually, the mscdfr0-type instructions are the ones I hate. eieio is just fun for jokes though it has practical use as a lightweight barrier. But sheer number of instructions aside, RISC really is now just parlance for load-store. In that sense FISC might be more appropriate: https://news.ycombinator.com/item?id=28601455

ARM is just as bad (in fact worse due to their crazy encodings), and I think RISC-V will eventually metastasize. Even MIPS is getting that way. That said, I'll also add as someone handcoding assembly right now for the Firefox JIT that it was so nice to finally have instructions for GPR<->FPR moves in VSX plus a lot more rounding-type instructions rather than having to serialize the FPSCR by twiddling bits. And VSX is way more complete than VMX used to be (I had to tie myself in knots to write good AltiVec routines). ISA 3.0 added a whopping number of instructions to what was already a large instruction set but I find I'm actually using them.

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