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#
# Copyright (c) 2006 Martin Decky
# Copyright (c) 2006 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
# 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 <stack.h>
#include <register.h>

.register       %g2, #scratch
.register       %g3, #scratch

.text

.global halt
.global memcpy
.global jump_to_kernel

halt:
    b halt
    nop
    
memcpy:
    mov %o0, %o3        ! save dst
    add %o1, 7, %g1
    and %g1, -8, %g1
    cmp %o1, %g1
    be,pn   %xcc, 3f
    add %o0, 7, %g1
    mov 0, %g3
0:
    brz,pn  %o2, 2f
    mov 0, %g2
1:
    ldub    [%g3 + %o1], %g1
    add %g2, 1, %g2
    cmp %o2, %g2
    stb %g1, [%g3 + %o0]
    bne,pt  %xcc, 1b
    mov %g2, %g3
2:
    jmp %o7 + 8         ! exit point
    mov %o3, %o0
3:
    and %g1, -8, %g1
    cmp %o0, %g1
    bne,pt  %xcc, 0b
    mov 0, %g3
    srlx    %o2, 3, %g4
    brz,pn  %g4, 5f
    mov 0, %g5
4:
    sllx    %g3, 3, %g2
    add %g5, 1, %g3
    ldx [%o1 + %g2], %g1
    mov %g3, %g5
    cmp %g4, %g3
    bne,pt  %xcc, 4b
    stx %g1, [%o0 + %g2]
5:
    and %o2, 7, %o2
    brz,pn  %o2, 2b
    sllx    %g4, 3, %g1
    mov 0, %g2
    add %g1, %o0, %o0
    add %g1, %o1, %g4
    mov 0, %g3
6:
    ldub    [%g2 + %g4], %g1
    stb %g1, [%g2 + %o0]
    add %g3, 1, %g2
    cmp %o2, %g2
    bne,pt  %xcc, 6b
    mov %g2, %g3

    jmp %o7 + 8         ! exit point
    mov %o3, %o0

jump_to_kernel:
    /*
     * We have copied code and now we need to guarantee cache coherence.
     * 1. Make sure that the code we have moved has drained to main memory.
     * 2. Invalidate I-cache.
     * 3. Flush instruction pipeline.
     */

    /*
     * US3 processors have a write-invalidate cache, so explicitly
     * invalidating it is not required. Whether to invalidate I-cache
     * or not is decided according to the value of the ver.impl bits
     * in the Version register.
     */
! the lowest/greatest value of ver.impl for US3
#define FIRST_US3_CPU 0x14
#define LAST_US3_CPU 0x19
    rdpr %ver, %g2          ! autodetect CPU using the Version register
    sllx %g2, 16, %g2       ! extract ver.impl bits
    srlx %g2, 48, %g2
    addcc %g2, -FIRST_US3_CPU, %g0  ! flush if ver.impl < FISRT_US3_CPU
    bl 0f
    nop
    addcc %g2, -LAST_US3_CPU, %g0   ! flush if ver.impl > LAST_US3_CPU
    bg 0f
    nop
    ba 1f
    nop
0:
    call icache_flush
    nop
1:
    
    membar #StoreStore
    
    /*
     * Flush the instruction pipeline.
     */
    flush   %i7

    mov %o0, %l1
    mov %o1, %o0
    mov %o2, %o1
    mov %o3, %o2
    jmp %l1             ! jump to kernel
    nop

#define ICACHE_SIZE     8192
#define ICACHE_LINE_SIZE    32
#define ICACHE_SET_BIT      (1 << 13)
#define ASI_ICACHE_TAG      0x67

# Flush I-cache
icache_flush:
    set ((ICACHE_SIZE - ICACHE_LINE_SIZE) | ICACHE_SET_BIT), %g1
    stxa    %g0, [%g1] ASI_ICACHE_TAG
0:  membar  #Sync
    subcc   %g1, ICACHE_LINE_SIZE, %g1
    bnz,pt  %xcc, 0b
    stxa    %g0, [%g1] ASI_ICACHE_TAG
    membar  #Sync
    retl
    ! SF Erratum #51
    nop
.global ofw
ofw:
    save %sp, -STACK_WINDOW_SAVE_AREA_SIZE, %sp
    set ofw_cif, %l0
    ldx [%l0], %l0

    rdpr  %pstate, %l1
    and  %l1, ~PSTATE_AM_BIT, %l2
    wrpr  %l2, 0, %pstate
    
    jmpl %l0, %o7
    mov %i0, %o0

    wrpr %l1, 0, %pstate

    ret
    restore %o0, 0, %o0