/*
 * Copyright (c) 2018, 2020 Ariadne Conill <ariadne@dereferenced.org>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * This software is provided 'as is' and without any warranty, express or
 * implied.  In no event shall the authors be liable for any damages arising
 * from the use of this software.
 */

#include "defs.h"

ALIAS(swapcontext, __swapcontext)

FUNC(__swapcontext)
	/* copy all of the current registers into the ucontext structure */
	add	r2, r0, #REG_OFFSET(0)
	stmia	r2, {r0-r12}
	str	r13, [r0,#REG_OFFSET(13)]
	str	r14, [r0,#REG_OFFSET(15)]

	/* load new registers from the second ucontext structure */
	add	r14, r1, #REG_OFFSET(0)
	ldmia	r14, {r0-r12}
	ldr	r13, [r14, #52]
	add	r14, r14, #56
	ldmia	r14, {r14, pc}
END(__swapcontext)