/*      $NetBSD: sh3.s,v 1.1 2022/10/14 19:41:18 ryo Exp $      */

/*-
 * Copyright (c) 2022 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

/*
 * assemble & link:
 *  as -o sh3.o sh3.s
 *  ld -o hello -e __start sh3.o
 */

        /* ------------------------------------------------------------------ */

        /*
         * This ELF section is used by the kernel to determine, among other
         * things, the system call interface used by the binary.
         *
         * Normally, /usr/lib/crti.o is linked, but here it is written manually.
         *
         * SEE ALSO:
         * - http://www.netbsd.org/docs/kernel/elf-notes.html
         * - src/sys/sys/exec_elf.h
         * - src/lib/csu/common/sysident.S
         * - src/lib/csu/arch/sh3/crti.S
         */
        .section ".note.netbsd.ident", "a"
        .p2align 2
        .long   7               /* ELF_NOTE_NETBSD_NAMESZ */
        .long   4               /* ELF_NOTE_NETBSD_DESCSZ */
        .long   1               /* ELF_NOTE_TYPE_NETBSD_TAG */
        .ascii  "NetBSD\0\0"    /* ELF_NOTE_NETBSD_NAME */
        .long   999010000       /* __NetBSD_Version__ (sys/sys/param.h) */


        /* ------------------------------------------------------------------ */

        .section ".rodata"
message:
        .ascii "Hello, world!\n"
        .set MESSAGE_SIZE, . - message


        /* ------------------------------------------------------------------ */

        .section ".text"
        .p2align 2

        .global __start
        .type _start, %function
__start:
        /* write(STDOUT_FILENO, message, MESSAGE_SIZE) */
        mov     #1, r4                  /* r4: fd = STDOUT_FILENO */
        mov.l   .Lmessage, r5           /* r5: buf = message */
        mov     #MESSAGE_SIZE, r6       /* r6: nbytes = MESSAGE_SIZE */
        mov     #4, r0                  /* SYS_write */
        trapa   #0x80

        /* exit(0) */
        mov     #0, r4                  /* r4: status = 0 */
        mov     #1, r0                  /* SYS_exit */
        trapa   #0x80

        .p2align 2
.Lmessage:
        .long   message

        .size __start, . - __start