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Diffstat (limited to 'runtime/powerpc/i64_smulh.s')
| -rw-r--r-- | runtime/powerpc/i64_smulh.s | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/runtime/powerpc/i64_smulh.s b/runtime/powerpc/i64_smulh.s new file mode 100644 index 00000000..73393fce --- /dev/null +++ b/runtime/powerpc/i64_smulh.s @@ -0,0 +1,80 @@ +# ***************************************************************** +# +# 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. PowerPC version. + + .text + +### Signed multiply-high + +# 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 + + .balign 16 + .globl __compcert_i64_smulh +__compcert_i64_smulh: +# r7:r8:r9 accumulate bits 127:32 of the full unsigned product + mulhwu r9, r4, r6 # r9 = high half of XL.YL + mullw r0, r4, r5 # r0 = low half of XL.YH + addc r9, r9, r0 + mulhwu r0, r4, r5 # r0 = high half of XL.YH + addze r8, r0 + mullw r0, r3, r6 # r0 = low half of XH.YL + addc r9, r9, r0 + mulhwu r0, r3, r6 # r0 = high half of XH.YL + adde r8, r8, r0 + li r7, 0 + addze r7, r7 + mullw r0, r3, r5 # r0 = low half of XH.YH + addc r8, r8, r0 + mulhwu r0, r3, r5 # r0 = high half of XH.YH + adde r7, r7, r0 +# Here r7:r8 contains the high 64 bits of the unsigned product. +# Now, test signs and subtract if needed + srawi r0, r3, 31 # r0 = -1 if X < 0, r0 = 0 if X >= 0 + srawi r9, r5, 31 # r9 = -1 if Y < 0, r9 = 0 if Y >= 0 + and r3, r3, r9 # set X = 0 if Y >= 0 + and r4, r4, r9 + and r5, r5, r0 # set Y = 0 if X >= 0 + and r6, r6, r0 + subfc r8, r4, r8 # subtract X + subfe r7, r3, r7 + subfc r4, r6, r8 # subtract Y + subfe r3, r5, r7 + blr + .type __compcert_i64_smulh, @function + .size __compcert_i64_smulh, .-__compcert_i64_smulh + |