mirror of
https://github.com/autc04/Retro68.git
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264 lines
7.0 KiB
ArmAsm
264 lines
7.0 KiB
ArmAsm
/*
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* crt0_cfe.S -- Runtime startup for MIPS targets running CFE.
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*
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* Copyright 2003
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* Broadcom Corporation. All rights reserved.
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*
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* This software is furnished under license and may be used and copied only
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* in accordance with the following terms and conditions. Subject to these
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* conditions, you may download, copy, install, use, modify and distribute
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* modified or unmodified copies of this software in source and/or binary
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* form. No title or ownership is transferred hereby.
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*
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* 1) Any source code used, modified or distributed must reproduce and
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* retain this copyright notice and list of conditions as they appear in
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* the source file.
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*
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* 2) No right is granted to use any trade name, trademark, or logo of
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* Broadcom Corporation. The "Broadcom Corporation" name may not be
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* used to endorse or promote products derived from this software
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* without the prior written permission of Broadcom Corporation.
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*
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* 3) THIS SOFTWARE IS PROVIDED "AS-IS" AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING BUT NOT LIMITED TO, ANY IMPLIED WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR
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* NON-INFRINGEMENT ARE DISCLAIMED. IN NO EVENT SHALL BROADCOM BE LIABLE
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* FOR ANY DAMAGES WHATSOEVER, AND IN PARTICULAR, BROADCOM SHALL NOT BE
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* LIABLE FOR DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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* OR OTHERWISE), EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Derived from crt0_cygmon.S:
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*
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* Copyright (c) 1995, 1996, 1997, 2000 Red Hat, Inc.
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*
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* The authors hereby grant permission to use, copy, modify, distribute,
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* and license this software and its documentation for any purpose, provided
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* that existing copyright notices are retained in all copies and that this
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* notice is included verbatim in any distributions. No written agreement,
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* license, or royalty fee is required for any of the authorized uses.
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* Modifications to this software may be copyrighted by their authors
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* and need not follow the licensing terms described here, provided that
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* the new terms are clearly indicated on the first page of each file where
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* they apply.
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*/
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/*
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* This file does minimal runtime startup for code running under
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* CFE firmware.
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*
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* It does minimal hardware initialization. In particular
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* it sets Status:FR to match the requested floating point
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* mode.
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*
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* It is meant to be linked with the other files provided by libcfe.a,
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* and calls routines in those files.
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*/
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#ifdef __mips16
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/* This file contains 32 bit assembly code. */
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.set nomips16
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#endif
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#ifdef __mips_embedded_pic
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# error -membedded-pic is not supported.
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#endif
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#include "regs.S"
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/*
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* Set up some room for a stack. We just grab a chunk of memory.
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*/
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#define STARTUP_STACK_SIZE (1 * 1024)
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.comm _lstack, STARTUP_STACK_SIZE
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.text
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.align 4
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/*
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* Without the following nop, GDB thinks _start is a data variable.
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* This is probably a bug in GDB in handling a symbol that is at the
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* start of the .text section.
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*/
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nop
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/*
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* On entry, the following values have been passed in registers
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* by the firmware:
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*
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* a0: firmware handle
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* a1: zero (unused)
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* a2: firmware callback entrypoint
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* a3: CFE entrypoint seal (unused)
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*
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* They must be preserved until the CFE entrypoint and handle
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* are passed to __libcfe_init().
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*/
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.globl _start
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.ent _start
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_start:
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.set noreorder
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/* Set the global data pointer, defined in the linker script. */
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la gp, _gp
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#ifndef __mips_soft_float
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/* If compiled for hard float, set the FPU mode based on the
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compilation flags. Note that this assumes that enough code
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will run after the mtc0 to clear any hazards. */
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mfc0 t0, C0_SR
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or t0, t0, (SR_CU1 | SR_FR)
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#if (__mips_fpr == 32)
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xor t0, t0, SR_FR /* If 32-bit FP mode, clear FR. */
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#endif
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mtc0 t0, C0_SR
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#endif
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.end _start
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/*
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* zero out the bss section.
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*/
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.globl _zerobss
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.ent _zerobss
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_zerobss:
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/* These variables are defined in the linker script. */
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la v0, _fbss
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la v1, _end
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3:
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sw zero, 0(v0)
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bltu v0, v1, 3b
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addiu v0, v0, 4 /* Delay slot. */
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.end _zerobss
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/*
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* Setup a small stack so we can run some C code, and do
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* the library initialization. (32 bytes are saved for
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* the argument registers' stack slots.)
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*/
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.globl _stackinit
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.ent _stackinit
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_stackinit:
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la t0, _lstack
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addiu sp, t0, (STARTUP_STACK_SIZE - 32)
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jal __libcfe_init
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nop
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/*
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* Setup the stack pointer --
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* __libcfe_init() returns the value to be used as the top of
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* the program's stack.
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*
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* We subtract 32 bytes for the 4 argument registers, in case
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* main() wants to write them back to the stack. The caller
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* allocates stack space for parameters in the old MIPS ABIs.
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* We must do this even though we aren't passing arguments,
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* because main might be declared to have them.)
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*
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* We subtract 32 more bytes for the argv/envp setup for the
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* call to main().
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*/
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subu v0, v0, 64
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move sp, v0
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.end _stackinit
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/*
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* initialize target specific stuff. Only execute these
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* functions it they exist.
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*/
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.globl hardware_init_hook .text
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.globl software_init_hook .text
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.type _fini,@function
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.type _init,@function
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.globl atexit .text
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.globl exit .text
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.globl _crt0init
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.ent _crt0init
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_crt0init:
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la t9, hardware_init_hook # init the hardware if needed
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beq t9, zero, 6f
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nop
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jal t9
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nop
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6:
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la t9, software_init_hook # init the software if needed
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beq t9, zero, 7f
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nop
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jal t9
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nop
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7:
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la a0, _fini
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jal atexit
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nop
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#ifdef GCRT0
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.globl _ftext
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.globl _extext
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la a0, _ftext
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la a1, _etext
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jal monstartup
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nop
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#endif
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jal _init # run global constructors
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nop
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addiu a1,sp,32 # argv = sp + 32
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addiu a2,sp,40 # envp = sp + 40
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#if __mips64
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sd zero,(a1) # argv[argc] = 0
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sd zero,(a2) # envp[0] = 0
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#else
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sw zero,(a1)
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sw zero,(a2)
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#endif
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jal main # call the program start function
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move a0,zero # set argc to 0; delay slot.
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# fall through to the "exit" routine
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jal exit # call libc exit to run the G++
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# destructors
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move a0, v0 # pass through the exit code
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.end _crt0init
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/*
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* _exit -- Exit from the application. This is provided in this file because
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* program exit should shut down profiling (if GCRT0 is defined),
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* and only this file is compiled with GCRT0 defined.
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*/
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.globl _exit
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.ent _exit
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_exit:
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7:
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move s0, a0 /* Save in case we loop. */
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#ifdef GCRT0
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jal _mcleanup
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nop
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#endif
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la t0, hardware_exit_hook
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beq t0,zero,1f
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nop
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jal t0
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nop
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1:
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/* Call into the library to do the heavy lifting. */
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jal __libcfe_exit
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move a0, s0 /* Delay slot. */
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b 7b /* Loop back just in case. */
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nop
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.end _exit
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/* EOF crt0_cfe.S */
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