From: Xi Ruoyao <xry111@xry111.site>
To: Andreas Schwab <schwab@suse.de>, caiyinyu <caiyinyu@loongson.cn>
Cc: libc-alpha@sourceware.org, adhemerval.zanella@linaro.org
Subject: Re: [PATCH] LoongArch: Add Syscall Assembly Implementation
Date: Thu, 23 Mar 2023 21:34:06 +0800 [thread overview]
Message-ID: <80f6afc82e1b03d69a744e1707131f27995db455.camel@xry111.site> (raw)
In-Reply-To: <mvmjzz7wr1b.fsf@suse.de>
On Thu, 2023-03-23 at 14:12 +0100, Andreas Schwab wrote:
> On Mär 23 2023, caiyinyu wrote:
>
> > Without this patch(objdump -d libc.so...):
> >
> > 00000000000dd45c <syscall>:
> > dd45c: 02fec063 addi.d $sp, $sp, -80(0xfb0)
> > dd460: 02c0606c addi.d $t0, $sp, 24(0x18)
> > dd464: 29c06065 st.d $a1, $sp, 24(0x18)
> > dd468: 29c08066 st.d $a2, $sp, 32(0x20)
> > dd46c: 29c0a067 st.d $a3, $sp, 40(0x28)
> > dd470: 29c0c068 st.d $a4, $sp, 48(0x30)
> > dd474: 29c0e069 st.d $a5, $sp, 56(0x38)
> > dd478: 29c1206b st.d $a7, $sp, 72(0x48)
> > dd47c: 29c1006a st.d $a6, $sp, 64(0x40)
>
> If the argument registers are call-clobbbered, why does the compiler
> need to save them?
It seems triggered by va_start. If I don't use "..." and replace it
with "a0, a1, a2, ..., a5", and remove va_start ... va_end, the compiled
code won't save registers.
I'll try to investigate further.
--
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University
next prev parent reply other threads:[~2023-03-23 13:34 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-23 8:40 caiyinyu
2023-03-23 9:25 ` Xi Ruoyao
2023-03-23 12:01 ` caiyinyu
2023-03-23 13:12 ` Andreas Schwab
2023-03-23 13:34 ` Xi Ruoyao [this message]
2023-03-23 13:43 ` Xi Ruoyao
2023-03-23 17:34 ` Xi Ruoyao
2023-03-23 18:26 ` Xi Ruoyao
2023-03-23 18:40 ` Adhemerval Zanella Netto
2023-03-23 19:08 ` Xi Ruoyao
2023-03-23 13:12 ` Xi Ruoyao
2023-03-23 12:00 caiyinyu
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