/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8     -*-â
âvi: set et ft=asm ts=8 tw=8 fenc=utf-8                                     :viâ
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â Copyright 2020 Justine Alexandra Roberts Tunney                              â
â                                                                              â
â Permission to use, copy, modify, and/or distribute this software for         â
â any purpose with or without fee is hereby granted, provided that the         â
â above copyright notice and this permission notice appear in all copies.      â
â                                                                              â
â THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                â
â WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                â
â WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             â
â AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         â
â DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        â
â PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               â
â TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             â
â PERFORMANCE OF THIS SOFTWARE.                                                â
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#include "libc/macros.internal.h"
.testonly

//	Empties L1 instruction cache.
thrashcodecache:
#ifdef __x86_64__
	.leafprologue
	push	%rbx
	xor	%eax,%eax
	xor	%ecx,%ecx
	cpuid
	add	%r9,%r8
//	Generate 32kb of junk code clobbering r8,r9,r10,r11
	i = 0xdeadbeef
0:	.rept	32768/(3+7)
	rex.wrb
	.byte	0001|(i&030)			// ADD/OR/... Evqp Gvqp
	.byte	0300|(i&033)			// %r8-%r11 to %r8-%r11
	.byte	0x49,0x81,0360|(i&003)		// XOR immed32,%r8-%r11
	.long	i
	i = ((i * 1103515245 + 12345) >> 16) & 0xffffffff
	.endr
	xor	%eax,%eax
	xor	%ecx,%ecx
	cpuid
	pop	%rbx
	.leafepilogue
#else
	ret
#endif
	.endfn	thrashcodecache,globl
