I could try and build a spim world without the ADD in syscall to see what happens. It might be a week or 2 before I can find the time.
As for why it does it. I never really looked into it. I figured it was just another endian issue. I had enough bugs that when I got past that one I just moved on to the next. But I do need to set up a fresh 9 Front install to go through and get patches for all the mips and spim stuff. I also have a big-endian Atheros/Qualcomm chip that I need to get around to building a kernel for, and then there will be a close to 1 to 1 chip to compare mips and spim stuff. On Thu, Jan 26, 2023 at 6:47 PM Anthony Martin <al...@pbrane.org> wrote: > > Does anyone know why the libc system call functions for > spim add four to the stack pointer (R29) before issuing > the SYSCALL instruction? > > /sys/src/libc/9syscall/mkfile:/spim > > It was introduced in the third edition but there were > never any spim kernels released so I wasn't able to > compare the libc additions to the trap code. > > I was watching one of adventuresin9's videos about his > ongoing port to the MediaTek MT7688 and he mentioned > having to modify the stack offsets in the syscall trap > handler just as cherry9 had done for the loongson port. > > Is there any reason not to simply get rid of that ADD $4? > > Cheers, > Anthony ------------------------------------------ 9fans: 9fans Permalink: https://9fans.topicbox.com/groups/9fans/T589fa55313abbdb4-M3df698a73959945f954ae172 Delivery options: https://9fans.topicbox.com/groups/9fans/subscription
