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rtld: Microoptimize rtld_start on i386

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Initial stack pointer is preserved in calle-saved %esi,
use it bellow to pass initial stack pointer to _rtld().

Reviewed by:		kib
Differential Revision:	https://reviews.freebsd.org/D40950
This commit is contained in:
Dmitry Chagin 2023-07-11 15:10:08 +03:00
parent 972e60da74
commit 86c63225ea
1 changed files with 1 additions and 2 deletions
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3
libexec/rtld-elf/i386/rtld_start.S
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@ -31,7 +31,6 @@
.type .rtld_start,@function
.rtld_start:
xorl %ebp,%ebp # Clear frame pointer for good form
movl %esp,%eax # Save initial stack pointer
movl %esp,%esi # Save initial stack pointer
andl $0xfffffff0,%esp # Align stack pointer
subl $16,%esp # A place to store exit procedure addr
@ -41,7 +40,7 @@
subl $4,%esp # Keep stack aligned
pushl %ecx # Pass address of obj_main
pushl %ebx # Pass address of exit proc
pushl %eax # Pass initial stack pointer to rtld
pushl %esi # Pass initial stack pointer to rtld
call _rtld # Call rtld(sp); returns entry point
addl $16,%esp # Remove arguments from stack
popl %edx # Get exit procedure address