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@ *****************************************************************
@
@ The Compcert verified compiler
@
@ Xavier Leroy, INRIA Paris
@
@ Copyright (c) 2016 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. ARM version.
#include "sysdeps.h"
@@@ Multiply-high unsigned
@ X * Y = 2^64 XH.YH + 2^32 (XH.YL + XL.YH) + XL.YL
FUNCTION(__compcert_i64_umulh)
push {r4, r5, r6, r7}
@@@ r7:r6 accumulate bits 95-32 of the full product
umull r4, r6, Reg0LO, Reg1LO @ r6 = high half of XL.YL product
umull r4, r5, Reg0LO, Reg1HI @ r5:r4 = product XL.YH
adds r6, r6, r4
ADC r7, r5, #0 @ no carry out
umull r4, r5, Reg0HI, Reg1LO @ r5:r4 = product XH.YL
adds r6, r6, r4
adcs r7, r7, r5 @ carry out is possible
@@@ r6:r7 accumulate bits 127-64 of the full product
mov r6, #0
ADC r6, r6, #0 @ put carry out in bits 127-96
umull r4, r5, Reg0HI, Reg1HI @ r5:r4 = product XH.YH
adds Reg0LO, r7, r4
ADC Reg0HI, r6, r5
pop {r4, r5, r6, r7}
bx lr
ENDFUNCTION(__compcert_i64_umulh)
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