98 lines
2.8 KiB
ArmAsm
98 lines
2.8 KiB
ArmAsm
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/* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* crt0.S -- PRU startup code
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*
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* Copyright (c) 2018-2019 Dimitar Dimitrov <dimitar@dinux.eu>
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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 ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "newlib.h"
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.extern main
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.extern exit
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.text
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.section .init0, "x"
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.global _start
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_start:
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/* Initialize stack pointer. */
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ldi32 sp, _stack_top
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/* DATA and BSS are handled by the loader, so nothing to do here. */
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#if !defined(MINRT)
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.extern _do_global_dtors
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/* Ensure destructors get called. Call is per GNU ABI (i.e. 32-bit
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function pointers). But it is also compatible with the TI ABI
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since GCC supports only little endian PRU.
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WARNING: Keep this compatible with both ABIs! */
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ldi r14, %pmem(_do_global_dtors)
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call atexit
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/* Call constructors. Use non-call-clobbered registers. */
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ldi r5, __init_array_start
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ldi r6, __init_array_end
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ctors_loop:
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qbeq ctors_done, r5, r6
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/* ABI dictates 16-bit IMEM pointers. */
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lbbo r7, r5, 0, 2
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call r7.w0
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add r5, r5, 2
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jmp ctors_loop
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ctors_done:
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#endif
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/* Just in case main() tries to access argc, argv[] and envp. */
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zero r14, 3 * 4
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#if !defined(MINRT)
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.weak __c_args__
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ldi32 r5, __c_args__
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qbeq __skip_c_args, r5, 0
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lbbo r14, r5, 0, 4 /* argc */
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add r15, r5, 4 /* argv */
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__skip_c_args:
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#endif
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/* Call main */
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call main
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#if !defined(MINRT)
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/* Call exit */
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call exit
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#endif
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/* We should never reach here. */
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_crt_exit:
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halt
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jmp _crt_exit
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/* PRU obviously has no shared libraries, but dso_handle
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helps to achieve better GCC test coverage. Besides,
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it should be free with minrt. */
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.section .data
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.global __dso_handle
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.weak __dso_handle
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__dso_handle:
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.long 0
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