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Diffstat (limited to 'runtime/arm/i64_umulh.S')
| -rw-r--r-- | runtime/arm/i64_umulh.S | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/runtime/arm/i64_umulh.S b/runtime/arm/i64_umulh.S new file mode 100644 index 00000000..c14f0c6b --- /dev/null +++ b/runtime/arm/i64_umulh.S @@ -0,0 +1,61 @@ +@ ***************************************************************** +@ +@ 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(__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(__i64_umulh) |