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#
# Copyright (C) 2006 Martin Decky
# 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 "regname.h"

.data

flush_buffer:
    .space (L1_CACHE_LINES * L1_CACHE_BYTES)

.text

.global memsetb
.global memcpy
.global flush_instruction_cache
.global jump_to_kernel

memsetb:
    rlwimi r5, r5, 8, 16, 23
    rlwimi r5, r5, 16, 0, 15
    
    addi r14, r3, -4
    
    cmplwi 0, r4, 4
    blt 7f
    
    stwu r5, 4(r14)
    beqlr
    
    andi. r15, r14, 3
    add r4, r15, r4
    subf r14, r15, r14
    srwi r15, r4, 2
    mtctr r15
    
    bdz 6f
    
    1:
        stwu r5, 4(r14)
        bdnz 1b
    
    6:
    
    andi. r4, r4, 3
    
    7:
    
    cmpwi 0, r4, 0
    beqlr
    
    mtctr r4
    addi r6, r6, 3
    
    8:
    
    stbu r5, 1(r14)
    bdnz 8b
    
    blr

memcpy:
    srwi. r7, r5, 3
    addi r6, r3, -4
    addi r4, r4, -4
    beq 2f
    
    andi. r0, r6, 3
    mtctr r7
    bne 5f
    
    1:
    
    lwz r7, 4(r4)
    lwzu r8, 8(r4)
    stw r7, 4(r6)
    stwu r8, 8(r6)
    bdnz 1b
    
    andi. r5, r5, 7
    
    2:
    
    cmplwi 0, r5, 4
    blt 3f
    
    lwzu r0, 4(r4)
    addi r5, r5, -4
    stwu r0, 4(r6)
    
    3:
    
    cmpwi 0, r5, 0
    beqlr
    mtctr r5
    addi r4, r4, 3
    addi r6, r6, 3
    
    4:
    
    lbzu r0, 1(r4)
    stbu r0, 1(r6)
    bdnz 4b
    blr
    
    5:
    
    subfic r0, r0, 4
    mtctr r0
    
    6:
    
    lbz r7, 4(r4)
    addi r4, r4, 1
    stb r7, 4(r6)
    addi r6, r6, 1
    bdnz 6b
    subf r5, r0, r5
    rlwinm. r7, r5, 32-3, 3, 31
    beq 2b
    mtctr r7
    b 1b
    
flush_instruction_cache:

    # Flush data cache
    
    lis r3, flush_buffer@h
    ori r3, r3, flush_buffer@l
    li r4, L1_CACHE_LINES
    mtctr r4
    
    0:
    
    lwz r4, 0(r3)
    addi r3, r3, L1_CACHE_BYTES
    bdnz 0b
    
    # Invalidate instruction cache
    
    li r3, 0
    ori r3, r3, (hid0_ice | hid0_dce | hid0_icfi | hid0_dci)
    mfspr r4, hid0
    or r5, r4, r3
    isync
    mtspr hid0, r5
    sync
    isync
    
    # Enable instruction cache
    
    ori r5, r4, hid0_ice
    mtspr hid0, r5
    sync
    isync
    blr

jump_to_kernel:
    
    # r3 = kernel_start (va)
    # r4 = memmap (pa)
    # r5 = real_mode (pa)
    
    mtspr srr0, r5
    
    # jumps to real_mode
    
    mfmsr r5
    lis r6, ~0@h
    ori r6, r6, ~(msr_ir | msr_dr)@l
    and r5, r5, r6
    mtspr srr1, r5
    rfi

.section REALMODE
.align 12
.global real_mode

real_mode:

    # fill segment registers

    li r5, 16
    mtctr r5
    li r5, 0
    li r6, 0
    
    seg_fill:
    
        mtsrin r6, r5
        addis r5, r5, 0x1000    # move to next SR
        addis r6, r6, 0x10      # add 256 MB, move to next SR
        
        bdnz seg_fill
    
    # bootstrap kernel
    #
    # r3 = kernel_start (va)
    # r4 = memmap (pa)       -> r10
    
    mtspr srr0, r3
    
    mfmsr r5
    ori r5, r5, (msr_ir | msr_dr)@l
    mtspr srr1, r5
    
    mr r10, r4
    rfi