libucontext/arch/or1k/swapcontext.S

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/*
* Copyright (c) 2022 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, libucontext_swapcontext)
ALIAS(__swapcontext, libucontext_swapcontext)
FUNC(libucontext_swapcontext)
/* copy context into r3 like getcontext */
l.sw REG_OFFSET(1)(r3), r1 /* store r1 and r2 */
l.sw REG_OFFSET(2)(r3), r2
l.sw REG_OFFSET(9)(r3), r9 /* store r9 to both r9 and r11 in the context */
l.sw REG_OFFSET(11)(r3), r9
l.sw REG_OFFSET(10)(r3), r10 /* store r10 for TLS */
l.sw REG_OFFSET(14)(r3), r14 /* store r14 through r30 even */
l.sw REG_OFFSET(16)(r3), r16
l.sw REG_OFFSET(18)(r3), r18
l.sw REG_OFFSET(20)(r3), r20
l.sw REG_OFFSET(22)(r3), r22
l.sw REG_OFFSET(24)(r3), r24
l.sw REG_OFFSET(26)(r3), r26
l.sw REG_OFFSET(28)(r3), r28
l.sw REG_OFFSET(30)(r3), r30
/* set the new context from r4 */
l.ori r30, r4, 0 /* copy r4 to r30 to avoid clobbering */
l.lwz r3, REG_OFFSET(3)(r30) /* restore r3-r8 (argument registers) */
l.lwz r4, REG_OFFSET(4)(r30)
l.lwz r5, REG_OFFSET(5)(r30)
l.lwz r6, REG_OFFSET(6)(r30)
l.lwz r7, REG_OFFSET(7)(r30)
l.lwz r8, REG_OFFSET(8)(r30)
l.lwz r1, REG_OFFSET(1)(r30) /* restore stack/frame pointers */
l.lwz r2, REG_OFFSET(2)(r30)
l.lwz r9, REG_OFFSET(9)(r30) /* restore link register and starting address register */
l.lwz r11, REG_OFFSET(11)(r30)
l.lwz r10, REG_OFFSET(10)(r30) /* restore TLS register */
l.lwz r14, REG_OFFSET(14)(r30) /* restore r14-r30, even only */
l.lwz r16, REG_OFFSET(16)(r30)
l.lwz r18, REG_OFFSET(18)(r30)
l.lwz r20, REG_OFFSET(20)(r30)
l.lwz r22, REG_OFFSET(22)(r30)
l.lwz r24, REG_OFFSET(24)(r30)
l.lwz r26, REG_OFFSET(26)(r30)
l.lwz r28, REG_OFFSET(28)(r30)
l.lwz r30, REG_OFFSET(30)(r30)
l.jr r11 /* jump to new starting address */
l.ori r11, r0, 0
END(libucontext_swapcontext)