54 lines
1.5 KiB
ArmAsm
54 lines
1.5 KiB
ArmAsm
/*
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* Copyright (c) 2018, 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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#include "defs.h"
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ALIAS(swapcontext, libucontext_swapcontext)
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ALIAS(__swapcontext, libucontext_swapcontext)
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FUNC(libucontext_swapcontext)
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#ifndef FORCE_SOFT_FLOAT
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#ifndef FORCE_HARD_FLOAT
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/* test for vfp magic number, copy to other ucontext */
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ldr r3, [r1, #VFP_MAGIC_OFFSET]
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ldr r4, =#0x56465001
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str r3, [r0, #VFP_MAGIC_OFFSET]
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cmp r3, r4
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bne 1f
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#endif
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/* if vfp in use, save and restore d8-d15 */
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.fpu vfp
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add r2, r0, #VFP_D8_OFFSET
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vstmia r2, {d8-d15}
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add r14, r1, #VFP_D8_OFFSET
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vldmia r14, {d8-d15}
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.fpu softvfp
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1:
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#endif
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/* copy all of the current registers into the ucontext structure */
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str r13, [r0,#REG_OFFSET(13)]
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str r14, [r0,#REG_OFFSET(15)]
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add r2, r0, #REG_OFFSET(0)
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/* copy r0 with value 0 to indicate success (return value 0) */
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mov r0, #0
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stmia r2, {r0-r12}
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/* load new registers from the second ucontext structure */
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add r14, r1, #REG_OFFSET(0)
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ldmia r14, {r0-r12}
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ldr r13, [r14, #52]
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add r14, r14, #56
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ldmia r14, {r14, pc}
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END(libucontext_swapcontext)
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