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#
# Copyright (C) 2005 Jakub Jermar
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# - Redistributions of source code must retain the above copyright
#   notice, this list of conditions and the following disclaimer.
# - 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.
# - 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
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# (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 <arch/register.h>

.text

/** Copy memory from/to userspace.
 *
 * This memcpy() has been taken from the assembler output of
 * the generic _memcpy() and modified to have the failover part.
 *
 * @param in0 Destination address.
 * @param in1 Source address.
 * @param in2 Number of byte to copy.
 */
.global memcpy
.global memcpy_from_uspace
.global memcpy_to_uspace
.global memcpy_from_uspace_failover_address
.global memcpy_to_uspace_failover_address
memcpy:
memcpy_from_uspace:
memcpy_to_uspace:
    alloc loc0 = ar.pfs, 3, 1, 0, 0

    shr.u r18 = in2, 3
    mov r8 = in1 ;;         /* prepare to return in1 on success */
    cmp.ne p6, p7 = 0, r18  ;;
(p7)    mov r17 = r0
(p7)    br.cond.dptk 1f ;;
    mov r16 = r0
    mov r17 = r0 ;;

0:
    shladd r14 = r17, 3, r0
    adds r16 = 1, r16 ;;
    add r15 = r14, r8
    sxt4 r17 = r16
    add r14 = r14, in0 ;;
    ld8 r15 = [r15]
    cmp.gtu p6, p7 = r18, r17 ;;
    st8 [r14] = r15
(p6)    br.cond.dptk 0b

1:
    and in2 = 7, in2 ;;
    cmp.eq p6, p7 = 0, in2 ;;
(p6)    mov ar.pfs = loc0
(p6)    br.ret.dptk.many rp
    shladd r14 = r17, 3, r0
    mov r16 = r0
    mov r17 = r0 ;;
    add in0 = in0, r14
    add r18 = r8, r14 ;;

2:
    add r14 = r16, r18
    adds r17 = 1, r17
    add r15 = in0, r16 ;;
    ld1 r14 = [r14]
    sxt4 r16 = r17  ;;
    st1 [r15] = r14
    cmp.gtu p6, p7 = in2, r16
(p6)    br.cond.dptk 2b

    mov ar.pfs = loc0
    br.ret.sptk.many rp
    
memcpy_from_uspace_failover_address:
memcpy_to_uspace_failover_address:
    mov r8 = r0         /* return 0 on failure */
    mov ar.pfs = loc0
    br.ret.sptk.many rp

.global memsetb
memsetb:
    br _memsetb

.global cpu_halt
cpu_halt:
    br cpu_halt

.global panic_printf
panic_printf:
    {
        br.call.sptk.many b0=printf
    }
    br halt

/** Switch to userspace - low level code.
 *
 * @param in0 Userspace entry point address.
 * @param in1 Userspace stack pointer address.
 * @param in2 Userspace register stack pointer address.
 * @param in3 Userspace address of thread uspace_arg_t structure.
 * @param in4 Value to be stored in IPSR.
 * @param in5 Value to be stored in RSC.
 */
.global switch_to_userspace
switch_to_userspace:
    alloc loc0 = ar.pfs, 6, 3, 0, 0
    rsm (PSR_IC_MASK | PSR_I_MASK)      /* disable interruption collection and interrupts */
    srlz.d ;;
    srlz.i ;;
    
    mov cr.ipsr = in4
    mov cr.iip = in0
    mov r12 = in1

    xor r1 = r1, r1
    
    mov loc1 = cr.ifs
    movl loc2 = PFM_MASK ;;
    and loc1 = loc2, loc1 ;;
    mov cr.ifs = loc1 ;;            /* prevent decrementing BSP by rfi */

    invala
    
    mov loc1 = ar.rsc ;;
    and loc1 = ~3, loc1 ;;          
    mov ar.rsc = loc1 ;;            /* put RSE into enforced lazy mode */

    flushrs ;;
    
    mov ar.bspstore = in2 ;;
    mov ar.rsc = in5 ;;
    
    mov r8 = in3
    
    rfi ;;