/* Copyright (C) 2023-2024 Free Software Foundation, Inc.

This file 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; either version 3, or (at your option) any
later version.

This file 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.

Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.

You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
<http://www.gnu.org/licenses/>.  */

#include "mips16.S"

#ifdef L_speculation_barrier

/* MIPS16e1 has no sync/jr.hb instructions, and MIPS16e2 lacks of jr.hb.
   So, we use normal MIPS code here, just like what we do for __sync_*.  */
	.set nomips16

	.set noreorder
	.globl	__speculation_barrier
	.ent	__speculation_barrier

__speculation_barrier:
	.set	push
#if __mips >= 2
	sync /* complementation barrier for memory.  */
#elif defined (__linux)
	/* MIPS1 has no sync, while Linux can trap&emu sync.  */
	/* FIXME: Will somebody use linux/gcc for MIPS1/baremetal?  */
	.word 0x0000000f
#endif


#if __mips_isa_rev >= 1
	/* Binutils claims that JR in R1 can do same as jr.hb.
	   R6 changes the encoding of jr.hb.  */
	jr.hb	$ra /* Jump with instruction hazard barrier.  */
#else
	/* ssnop is actually available since R5500,
	   and it will be decoded as nop on earlier processors.
	   gas can only recognize it with -march=mips1 since 2.21.
	   MIPS1 to MIPSr1: R10000 have 7 stage pipeline,
	   so 8 ssnop is sufficient to block all speculation on all CPUs.  */
	.rept 8
	.word	0x00000040 /* The encoding of ssnop.  */
	.endr
	/* jr.hb will be decoded as jr on earlier processors.  */
	.word	0x03e00408 /* The encoding of jr.hb $ra.  */
#endif
	.set	pop
	.end	__speculation_barrier

	.set reorder
#endif