<cr1901>
No, in ABC's case, C (C++?) doesn't make it exceptionally easy to do endian-independent "store/load word from smaller parts", and ABC, well, bakes in little-endian assumptions
<cr1901>
And when a yosys bug was filed that triggered the bug on big endian systems, it became clear that it's too much work to either add #ifdef BIG_ENDIAN or alter all the store/loads into endian-independent ones
<sorear>
<lofty> mwk: Trying to find big-endian hardware for these things is hard, but at least I discovered it >.>
<sorear>
i was asking what that meant
<mwk>
... I swear if we keep finding abc endianness / pointer-size issues, I'm putting it into a wasm32 jail where it belongs and shipping yosys with wasi interpreter
<whitequark>
mwk: don't need an interpreter
<whitequark>
use wasm2c
<whitequark>
i'm excited for yowasp to be shipping two nested layers of wasm runtimes
<cr1901>
sorear: Hmmm... what big endian CPUs still have hardware made for them, new in, say, 2019 (before parts shortage)?
<mwk>
System Z, POWER
<sorear>
cr1901: I'm told you can run big endian VMs on all armv8 hardware, haven't gotten around to trying it yet
<mwk>
plus, well, technically ARM is bi, but noone really uses it that way
<cr1901>
RISCV allows big-endian as nonstandard, but yea no one is gonna use that either
<cr1901>
sorear: I don't understand what you mean. You can run big-endian emulators on x86 too. It's just not fast :P.
<cr1901>
Ahhh, that sounds stressful to implement, but good for ARM
<sorear>
that's why it's kvm and not general user applications - much smaller ABI surface to translate
<cr1901>
I can just imagine me trying to implement, say, a 68k JIT, and screwing up which part of a word I load/store when generate host code for insns that access memory
<cr1901>
(Sorry, 68k is still my go-to example for big endian :P)
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<cr1901>
mwk: I forgot POWER was big-endian. I have plans to try out MicroWatt running Linux too
<mwk>
POWER is migrating to little-endian though
<mwk>
like, big-endian is still a thing, but it's becoming legacy
<cr1901>
Shame... they got bought out by the little-endian lobbyists :P
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<Xark>
Thank goodness PowerPC on PS3 also had a "little endian" load/store opcodes or it would have been a bummer running translated MIPS code. Perhaps last big-endian system in wide use...
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<mwk>
whitequark: so you mentioned you had some thoughts about poison, X, and UB in yosys; do you have that written down somewhere? I feel this is a discussion we need to have soon-ish about our IR