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author | Xavier Leroy <xavier.leroy@inria.fr> | 2016-10-25 15:11:30 +0200 |
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committer | Xavier Leroy <xavier.leroy@inria.fr> | 2016-10-25 15:11:30 +0200 |
commit | 1f004665758e26e6e48d13f5702fe55af8944448 (patch) | |
tree | e3ccaee73c86ec1aef94ef66341610ed4436f93a /runtime/arm/i64_smulh.S | |
parent | 271a6f98809fbeac6cb04fb29fccbcf9c1e18335 (diff) | |
download | compcert-1f004665758e26e6e48d13f5702fe55af8944448.tar.gz compcert-1f004665758e26e6e48d13f5702fe55af8944448.zip |
Update ARM port. Not tested yet.
Diffstat (limited to 'runtime/arm/i64_smulh.S')
-rw-r--r-- | runtime/arm/i64_smulh.S | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/runtime/arm/i64_smulh.S b/runtime/arm/i64_smulh.S new file mode 100644 index 00000000..8e721c68 --- /dev/null +++ b/runtime/arm/i64_smulh.S @@ -0,0 +1,77 @@ +@ ***************************************************************** +@ +@ 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 signed + +@ Hacker's Delight section 8.3: +@ - compute high 64 bits of the unsigned product X * Y (see i64_umulh.S) +@ - subtract X if Y < 0 +@ - subtract Y if X < 0 + +FUNCTION(__i64_smulh) + 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 r7, r7, r4 + ADC r6, r6, r5 +@@@ subtract X if Y < 0 + cmp Reg1HI, #0 + itt lt + subs.lt r7, r7, Reg0LO + sbcs.lt r6, r6, Reg0HI +@@@ subtract Y if X < 0 + cmp Reg0HI, #0 + itt lt + subs.lt r7, r7, Reg1LO + sbcs.lt r6, r6, Reg1HI +@@@ return result in Reg0 pair + mov Reg0LO, r7 + mov Reg0HI, r6 + pop {r4, r5, r6, r7} + bx lr +ENDFUNCTION(__i64_smulh) |