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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.
#include "sysdeps.h"
@@@ Auxiliary function for division and modulus. Don't call from C
@ On entry: N = (r0, r1) numerator D = (r2, r3) divisor
@ On exit: Q = (r4, r5) quotient R = (r0, r1) remainder
@ Locals: M = (r6, r7) mask TMP = r8 temporary
FUNCTION(__compcert_i64_udivmod)
orrs r8, Reg1LO, Reg1HI @ is D == 0?
it eq
bxeq lr @ if so, return with unspecified results
MOV Reg2LO, #0 @ Q = 0
MOV Reg2HI, #0
MOV Reg3LO, #1 @ M = 1
MOV Reg3HI, #0
1: cmp Reg1HI, #0 @ while ((signed) D >= 0) ...
blt 2f
subs r8, Reg0LO, Reg1LO @ ... and N >= D ...
sbcs r8, Reg0HI, Reg1HI
blo 2f
adds Reg1LO, Reg1LO, Reg1LO @ D = D << 1
adc Reg1HI, Reg1HI, Reg1HI
adds Reg3LO, Reg3LO, Reg3LO @ M = M << 1
adc Reg3HI, Reg3HI, Reg3HI
b 1b
2: subs Reg0LO, Reg0LO, Reg1LO @ N = N - D
sbcs Reg0HI, Reg0HI, Reg1HI
orr Reg2LO, Reg2LO, Reg3LO @ Q = Q | M
orr Reg2HI, Reg2HI, Reg3HI
bhs 3f @ if N was >= D, continue
adds Reg0LO, Reg0LO, Reg1LO @ otherwise, undo what we just did
adc Reg0HI, Reg0HI, Reg1HI @ N = N + D
bic Reg2LO, Reg2LO, Reg3LO @ Q = Q & ~M
bic Reg2HI, Reg2HI, Reg3HI
3: lsrs Reg3HI, Reg3HI, #1 @ M = M >> 1
rrx Reg3LO, Reg3LO
lsrs Reg1HI, Reg1HI, #1 @ D = D >> 1
rrx Reg1LO, Reg1LO
orrs r8, Reg3LO, Reg3HI @ repeat while (M != 0) ...
bne 2b
bx lr
ENDFUNCTION(__compcert_i64_udivmod)
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