cosmopolitan/libc/testlib/thrashcodecache.S

43 lines
2.3 KiB
ArmAsm

/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8 -*-│
vi: set et ft=asm ts=8 tw=8 fenc=utf-8 :vi
Copyright 2020 Justine Alexandra Roberts Tunney
This program is free software; you can redistribute it and/or modify │
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License. │
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of │
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software │
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
*/
#include "libc/macros.h"
.source __FILE__
.testonly
/ Empties L1 instruction cache.
thrashcodecache:
.leafprologue
push %rbx
xor %eax,%eax
xor %ecx,%ecx
cpuid
/ pushpop 4,%rcx
0: .rept 32768/(8+9)
.byte 0x0f,0x1f,0x84,0,0,0,0,0 # fat nop x8
.byte 0x66,0x0f,0x1f,0x84,0,0,0,0,0 # fat nop x9
.endr
/ loop 0b
xor %eax,%eax
xor %ecx,%ecx
cpuid
pop %rbx
.leafepilogue
.endfn thrashcodecache,globl