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<stikonas>janneke: got some partial success with scaffold/hello.c

<stikonas>it compiles, runs and exists with 42 but didn't print anything

<stikonas>so I will have to debug what went wrong with printing

<stikonas>hmm, printing works if I comment out environ = envp in __init_io

<stikonas>probably something wrong with crt1.c then...

<stikonas>oh, it's actually variable padding that is broken...

<stikonas>!0x00 is encoded to .00000000 which ends up being empty in binary

<stikonas>it's coming from https://gitlab.com/janneke/mes/-/blob/wip-riscv/module/mescc/M1.scm#L139 ...

<oriansj>stikonas, janneke wouldn't the syscall numbers be best defined in the C library and thus asm ("li_____%a7,SYS_write"); would become asm ("rd_a7 !" SYSCALL_WRITE " addi");

<oriansj>Irvise_: well rain1 did a bit of work with TCC to get it into a state where it could compile GCC again (it for a bit there lost that ability)

<stikonas>oriansj: we do have them in syscall library

<stikonas>I might come back to it later

<stikonas>oriansj: though at the moment C library defines them as #defines

<stikonas>so it's not a string

<stikonas>anyway, I don't think I'll resolve that mescc global variable padding issue today

<stikonas>there is a hack to replace ! with % and overpad everything

<stikonas>but it's a bit ugly

<oriansj>stikonas: no you missed what I am pointing out

<oriansj> https://paste.debian.net/1280621/

<stikonas[m]>Yes, that does work

<oriansj>you just do #DEFINE SYSCALL_WRITE "64"

<stikonas[m]>But currently meslibc has 42 instead of "42"

<stikonas[m]>Oh but that can be solves

<stikonas[m]>I can just add

<oriansj>inside of #ifdef block to determine what architecture uses which values

<stikonas[m]>fputs("hello "'SYSCALL_HUH"" back", stdout)

<stikonas[m]>oriansj: anyway, the bigger issue is global variable padding with zeroes

<stikonas[m]>mescc just prints required number of !0x00

<stikonas[m]>Which is noop in word based hex2...

<oriansj>well we could switch it to the padding in M1 (aka <100 does 100 null bytes)

<stikonas[m]>We should discuss it with janneke anyway...

<oriansj>but if the goal is to padd to alignment < will work

<stikonas[m]>Alignment is optional in mescc right now

<oriansj>but alignment support is required in hex2 and padding support is required in M1

<stikonas[m]>But it will print wither sizeof(var) of !0x00 or register size of !0x00

<oriansj>so just output <sizeof(var)

<oriansj>if sizeof(var) is 42 => <42

<stikonas[m]>Yeah, that might work

<stikonas[m]>Though will still need rewriting that bit of mescc

<stikonas[m]>I guess here https://gitlab.com/janneke/mes/-/blob/wip-riscv/module/mescc/M1.scm#L233

<oriansj>but it would probably simplify things as no need to loop to produce a block of !0x00

<stikonas[m]>Well, it's scheme..., so no loop already

<stikonas[m]>It just creates a list of (0 0 0...) with that iota

<stikonas[m]>And there is another function that converts numbers to M1...

<stikonas[m]>Quite a bit different from how M2-Planet emits code...

<oriansj>yep

<stikonas[m]>Though after a few days it's getting a bit easier to write lisp...

<oriansj>yeah, the hardest bit of using Lisp is just remembering the names and the varargs behavior of functions

<sam_>haha yes

<sam_>glad it's not just me :)

<janneke>"<stikonas> [23:45:25] janneke: got some partial success with scaffold/hello.c"

<janneke>\o/

<janneke>oriansj, stikonas[m]: syscall defines for x86: https://git.savannah.gnu.org/cgit/mes.git/tree/lib/x86-mes/x86.M1#n327

<muurkha>hi joeyh_, thanks for writing git-annex and like a third of Debian

<[exa]><3

<stikonas>oriansj, janneke: I think I found a reasonably nice way to write out those riscv syscalls

<stikonas>oriansj's way didn't work I think because in mescc multiple strings are not concatenated, it has to be a single line string

<stikonas>but I managed to sort it out using macros

<stikonas>e.g. now it looks like asm(RISCV_SYSCALL(SYS_write));

<stikonas>amd then RISCV_SYSCALL is define via

<stikonas>#define MAKESTRING(s) #s

<stikonas>#define MAKESTRING2(str) MAKESTRING(rd_a7 ! ## str addi)

<stikonas>#define RISCV_SYSCALL(str) MAKESTRING2(str

<stikonas>so this way we only need to have one canonical place for syscall numbers (just in syscall.h)

<stikonas>well, there is probably another copy in m2 folder but that's unavoidable, M2-Planet is not capable of parsing such complex macros

<stikonas>still need to deal with the other problem...

<stikonas>that is adding zeroes to store global variables

<stikonas>hmm, I think I should actually more or less port M2-Planet's padding/global variable initialization code to mescc...

IRC channel logs

2023-05-19.log