/*      $NetBSD: srt0.s,v 1.3 2023/02/04 14:38:09 tsutsui Exp $ */
/*
 * Copyright (c) 1994 Rolf Grossmann
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Rolf Grossmann.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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>

/*
 * Startup code for standalone system
 */

        .text
ASENTRY_NOPROFILE(start)
        || clear bss (this should not hurt us i.e. cause an exception)
        movel   #_C_LABEL(edata),%a2    | start of BSS
        movel   #_C_LABEL(end),%a3      | end
Lclr:
        clrb    %a2@+                   | clear BSS
        cmpl    %a2,%a3                 | done?
        bne     Lclr                    | no, keep going

        movl    #0x0808,%d0
        movc    %d0,%cacr               | clear and disable on-chip cache(s)

        || catch exceptions myself
        movec   %vbr,%a3
        movel   %a3,save_vbr            | save register for restoration
        lea     vectbl,%a4
        movel   %a3@(4),%a4@(4)         | copy mg, just for sure
        movel   %a3@(180),%a4@(180)     | copy vector for trap #13
        movel   %a3@(124),%a4@(124)     | copy vector for int 7
        movec   %a4,%vbr                | use the new table

        || save mg as pi
        movel   %a3@(4),_C_LABEL(mg)

        || make sure we disallow interrupts
        movew   #0x2600,%sr

        || away we go
        movel   %sp@(4),%sp@-           | copy the argument we got
        jsr     _C_LABEL(main)          | call C
        addql   #4,%sp

        || restore prom vectors
        movel   save_vbr,%a0
        movec   %a0,%vbr

        || return kernel start address (still in d0)
        rts

ENTRY(_halt)
        movel   save_vbr,%a0
        movec   %a0,%vbr                | restore prom vbr
hloop:
        movel   #halt,%d0
        trap    #13                     | halt the system
        bra     hloop                   | and do not allow continuation

ASENTRY_NOPROFILE(astrap)
        moveml  %d0-%d7/%a0-%a7,%sp@-   | save all registers

        movel   %sp,%sp@-               | push pointer to registers
        jsr     _C_LABEL(trap)          | call C to handle things (dump regs)
        addql   #4,%sp
        tstl    %d0
        jeq     Lstop
        moveml  %sp@+,%d0-%d7/%a0-%a7
        rte
Lstop:
        bra     Lstop                   | stay here

        .data
save_vbr:
        .long 0
halt:
        .asciz "-h"

#define TRAP16 \
        VECTOR(astrap); VECTOR(astrap); VECTOR(astrap); VECTOR(astrap); \
        VECTOR(astrap); VECTOR(astrap); VECTOR(astrap); VECTOR(astrap); \
        VECTOR(astrap); VECTOR(astrap); VECTOR(astrap); VECTOR(astrap); \
        VECTOR(astrap); VECTOR(astrap); VECTOR(astrap); VECTOR(astrap);

vectbl:
        TRAP16
        TRAP16
        TRAP16
        TRAP16
        TRAP16
        TRAP16
        TRAP16
        TRAP16
        TRAP16
        TRAP16
        TRAP16
        TRAP16
        TRAP16
        TRAP16
        TRAP16
        TRAP16