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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 double float to unsigned 64-bit integer
.global __i64_dtou
__i64_dtou:
#ifdef VARIANT_hardfloat
fmrrd r0, r1, d0
#endif
cmp r1, #0 @ is double < 0 ?
blt 1f @ then it converts to 0
@ extract unbiased exponent ((HI & 0x7FF00000) >> 20) - (1023 + 52) in r2
@ note: 1023 + 52 = 1075 = 1024 + 51
@ note: (HI & 0x7FF00000) >> 20 = (HI << 1) >> 21
mov r2, r1, lsl #1
mov r2, r2, lsr #21
sub r2, r2, #51
sub r2, r2, #1024
@ check range of exponent
cmn r2, #52 @ if EXP < -52, double is < 1.0
blt 1f
cmp r2, #12 @ if EXP >= 64 - 52, double is >= 2^64
bge 2f
@ extract true mantissa
bic r1, r1, #0xFF000000
bic r1, r1, #0x00F00000 @ HI &= ~0xFFF00000
orr r1, r1, #0x00100000 @ HI |= 0x00100000
@ shift it appropriately
cmp r2, #0
blt 3f
@ EXP >= 0: shift left by EXP. Note that EXP < 12
rsb r3, r2, #32 @ r3 = 32 - amount
mov r1, r1, lsl r2
orr r1, r1, r0, lsr r3
mov r0, r0, lsl r2
bx lr
@ EXP < 0: shift right by -EXP. Note that -EXP <= 52 but can be >= 32
3: rsb r2, r2, #0 @ r2 = -EXP - shift amount
rsb r3, r2, #32 @ r3 = 32 - amount
mov r0, r0, lsr r2
orr r0, r0, r1, lsl r3
sub r3, r2, #32 @ r3 = amount - 32 (see i64_shr.s)
orr r0, r0, r1, lsr r3
mov r1, r1, lsr r2
bx lr
@ special cases
1: mov r0, #0 @ result is 0
mov r1, #0
bx lr
2: mvn r0, #0 @ result is 0xFF....FF (MAX_UINT)
mvn r1, #0
bx lr
.type __i64_dtou, %function
.size __i64_dtou, . - __i64_dtou
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