/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (C) 2023 Dmitry Chagin <dchagin@FreeBSD.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <machine/asm.h>


        .text
        .align 8

        /*
         * The program entry point
         *                %rdi          %rsi
         * void _start(char **ap, void (*cleanup)(void)) __dead2
         */
        .globl  _start
        .type   _start, @function
_start:
        .cfi_startproc
        .cfi_undefined %rip             /* Terminate call chain. */
        pushq   %rbp                    /* Align stack, terminate call chain. */
        .cfi_def_cfa_offset 8
        movq    %rsp, %rbp
        .cfi_offset %rbp, -16
        .cfi_def_cfa_register %rbp
#ifdef GCRT
        subq    $16, %rsp
#endif
        movq    %rsi, %rcx              /* cleanup */
        movslq  (%rdi), %rax            /* long *ap; tmpargc = *ap */
        leaq    0x8(%rdi), %rsi         /* argv = ap + 1 */
        leaq    0x10(%rdi, %rax, 8), %rdx /* env = ap + 2 + tmpargc */
        movl    %eax, %edi              /* argc = tmpargc */

#ifdef PIC
        /*
         * XXX. %rip relative addressing is not intended for use in the
         * large memory model due to the offset from %rip being limited
         * to 32 bits.
         */
        leaq    main@plt(%rip), %r8
#else
        movabsq $main, %r8
#endif
#ifdef GCRT
        movabsq $eprol, %r9
        movabsq $etext, %rax
        movq    %rax, (%rsp)
        /*
         *                    %edi  %rsi  %rdx  %rcx    %r8    %r9    (%rsp)
         * __libc_start1_gcrt(argc, argv, env, cleanup, main, &eprol, &etext)
         */
        callq   __libc_start1_gcrt
eprol:
#else
        /* __libc_start1(argc, argv, env, cleanup, main) */
        callq   __libc_start1
#endif
        int3
        .cfi_endproc
        .size   _start, . - _start

        .section .note.GNU-stack,"",%progbits