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# *****************************************************************
#
# The Compcert verified compiler
#
# Xavier Leroy, INRIA Paris-Rocquencourt
#
# Copyright (c) 2013 Institut National de Recherche en Informatique et
# en Automatique.
#
# 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.
# * Neither the name of the <organization> nor the
# names of its contributors may be used to endorse or promote products
# derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 <COPYRIGHT
# HOLDER> 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.
#
# *********************************************************************
# Helper functions for 64-bit integer arithmetic. PowerPC version.
.text
# Shift right unsigned
.balign 16
.globl __i64_shr
__i64_shr:
# On PowerPC, shift instructions with amount mod 64 >= 32 return 0
# lo = (lo >> amount) | (hi << (32 - amount)) | (hi >> (amount - 32))
# hi = hi >> amount
# if 0 <= amount < 32:
# (amount - 32) mod 64 >= 32, hence hi >> (amount - 32) == 0
# if 32 <= amount < 64:
# hi >> amount == 0
# (32 - amount) mod 64 >= 32, hence hi << (32 - amount) == 0
andi. r5, r5, 63 # take amount modulo 64
subfic r6, r5, 32 # r6 = 32 - amount
addi r7, r5, -32 # r7 = amount - 32
srw r4, r4, r5
slw r0, r3, r6
or r4, r4, r0
srw r0, r3, r7
or r4, r4, r0
srw r3, r3, r5
blr
.type __i64_shr, @function
.size __i64_shr, .-__i64_shr
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