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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. ARM version.
.text
@@@ Conversion from unsigned 64-bit integer to single float
.global __i64_utof
__i64_utof:
@ Check whether X < 2^53
movs r2, r1, lsr #21 @ test if X >> 53 == 0
beq 1f
@ X is large enough that double rounding can occur.
@ Avoid it by nudging X away from the points where double rounding
@ occurs (the "round to odd" technique)
mov r2, #0x700
orr r2, r2, #0xFF @ r2 = 0x7FF
and r3, r0, r2 @ extract bits 0 to 11 of X
add r3, r3, r2 @ r3 = (X & 0x7FF) + 0x7FF
@ bit 12 of r3 is 0 if all low 12 bits of X are 0, 1 otherwise
@ bits 13-31 of r3 are 0
orr r0, r0, r3 @ correct bit number 12 of X
bic r0, r0, r2 @ set to 0 bits 0 to 11 of X
@ Convert to double
1: fmsr s0, r0
fuitod d0, s0 @ convert low half to double (unsigned)
fmsr s2, r1
fuitod d1, s2 @ convert high half to double (unsigned)
fldd d2, .LC1 @ d2 = 2^32
fmacd d0, d1, d2 @ d0 = d0 + d1 * d2 = double value of int64
@ Round to single
fcvtsd s0, d0
#ifdef VARIANT_eabi
@ Return result in r0
fmrs r0, s0
#endif
bx lr
.type __i64_utof, %function
.size __i64_utof, . - __i64_utof
.balign 8
.LC1: .quad 0x41f0000000000000 @ 2^32 in double precision
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