56 lines
2.1 KiB
ArmAsm
56 lines
2.1 KiB
ArmAsm
/*-
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* Copyright (c) 2010 Juli Mallett.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <machine/asm.h>
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__FBSDID("$FreeBSD$");
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/*
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* This requires makecontext() to setup a valid GP for locating
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* _ctx_done rather than deriving GP from T9 on entry. Currently this
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* uses the GP inherited from getcontext() assuming that getcontext()
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* is in the same shared object as _ctx_done(). For N32 and N64, GP
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* is caller-save so will be preserved across the call to the callback
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* function. For O32, GP is callee-save, so save it in a different
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* caller-save register (S1) while invoking the callback. This is
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* done instead of the usual SETUP_GP/SAVE_GP to avoid disturbing the
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* stack frame setup by makecontext() for the callback function.
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*/
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ENTRY(_ctx_start)
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#ifdef __mips_o32
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move s1, gp
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#endif
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jalr t9
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#ifdef __mips_o32
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move gp, s1
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#endif
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move a0, s0
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PTR_LA t9, _ctx_done
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jalr t9
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break 0
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END(_ctx_start)
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