88 lines
2.6 KiB
ArmAsm
88 lines
2.6 KiB
ArmAsm
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/*
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* Copyright (c) 2020 Ariadne Conill <ariadne@dereferenced.org>
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* This software is provided 'as is' and without any warranty, express or
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* implied. In no event shall the authors be liable for any damages arising
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* from the use of this software.
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*/
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LOCALSZ = 2
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#include "defs.h"
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A1_OFFSET = FRAMESZ - (1 * REG_SZ)
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FUNC(__swapcontext)
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/* copy $gp, $sp, $fp to temporary registers so we don't clobber them */
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move $a2, $gp
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move $a3, $sp
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move $a4, $fp
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PUSH_FRAME(__swapcontext)
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/* set registers */
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sd $s0, ((16 * REG_SZ) + MCONTEXT_GREGS)($a0)
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sd $s1, ((17 * REG_SZ) + MCONTEXT_GREGS)($a0)
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sd $s2, ((18 * REG_SZ) + MCONTEXT_GREGS)($a0)
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sd $s3, ((19 * REG_SZ) + MCONTEXT_GREGS)($a0)
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sd $s4, ((20 * REG_SZ) + MCONTEXT_GREGS)($a0)
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sd $s5, ((21 * REG_SZ) + MCONTEXT_GREGS)($a0)
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sd $s6, ((22 * REG_SZ) + MCONTEXT_GREGS)($a0)
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sd $s7, ((23 * REG_SZ) + MCONTEXT_GREGS)($a0)
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sd $a2, ((28 * REG_SZ) + MCONTEXT_GREGS)($a0)
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sd $a3, ((29 * REG_SZ) + MCONTEXT_GREGS)($a0)
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sd $a4, ((30 * REG_SZ) + MCONTEXT_GREGS)($a0)
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sd $ra, ((31 * REG_SZ) + MCONTEXT_GREGS)($a0)
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sd $ra, (MCONTEXT_PC)($a0)
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/* copy new context address in $a1 to stack */
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sd $a1, A1_OFFSET($sp)
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/* load new context address into $v0 */
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ld $v0, A1_OFFSET($sp)
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/* load the registers */
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ld $a0, ((4 * REG_SZ) + MCONTEXT_GREGS)($v0)
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ld $a1, ((5 * REG_SZ) + MCONTEXT_GREGS)($v0)
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ld $a2, ((6 * REG_SZ) + MCONTEXT_GREGS)($v0)
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ld $a3, ((7 * REG_SZ) + MCONTEXT_GREGS)($v0)
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ld $a4, ((8 * REG_SZ) + MCONTEXT_GREGS)($v0)
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ld $a5, ((9 * REG_SZ) + MCONTEXT_GREGS)($v0)
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ld $a6, ((10 * REG_SZ) + MCONTEXT_GREGS)($v0)
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ld $a7, ((11 * REG_SZ) + MCONTEXT_GREGS)($v0)
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ld $s0, ((16 * REG_SZ) + MCONTEXT_GREGS)($v0)
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ld $s1, ((17 * REG_SZ) + MCONTEXT_GREGS)($v0)
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ld $s2, ((18 * REG_SZ) + MCONTEXT_GREGS)($v0)
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ld $s3, ((19 * REG_SZ) + MCONTEXT_GREGS)($v0)
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ld $s4, ((20 * REG_SZ) + MCONTEXT_GREGS)($v0)
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ld $s5, ((21 * REG_SZ) + MCONTEXT_GREGS)($v0)
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ld $s6, ((22 * REG_SZ) + MCONTEXT_GREGS)($v0)
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ld $s7, ((23 * REG_SZ) + MCONTEXT_GREGS)($v0)
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ld $gp, ((28 * REG_SZ) + MCONTEXT_GREGS)($v0)
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ld $sp, ((29 * REG_SZ) + MCONTEXT_GREGS)($v0)
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ld $fp, ((30 * REG_SZ) + MCONTEXT_GREGS)($v0)
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ld $ra, ((31 * REG_SZ) + MCONTEXT_GREGS)($v0)
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ld $t9, (MCONTEXT_PC)($v0)
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move $v0, $zero
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jr $t9
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fail:
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dla $t9, exit
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POP_FRAME(__swapcontext)
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move $v0, $zero
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jalr $t9
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END(__swapcontext)
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.weak swapcontext;
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swapcontext = __swapcontext;
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