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author | Giacomo Travaglini <giacomo.travaglini@arm.com> | 2017-10-18 01:18:46 +0100 |
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committer | Giacomo Travaglini <giacomo.travaglini@arm.com> | 2017-10-20 15:33:40 +0000 |
commit | e79c4c6f033581f84072ddb45d2ec9543c31af55 (patch) | |
tree | 7c060130bd1b863ddb2b7d4a69a2d7a181885ef9 /src/arch/arm/isa/insts/data64.isa | |
parent | 4b3fee098435f1980d0d101ce5a416935d3d6a8e (diff) | |
download | gem5-e79c4c6f033581f84072ddb45d2ec9543c31af55.tar.xz |
arch-arm: RBIT instruction using mirroring func
The high speed bit-reversing function is now used
for the Aarch64/32 RBIT instruction implementation.
Change-Id: Id5a8a93d928d00fd33ec4061fbb586b8420a1c1b
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/5262
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Diffstat (limited to 'src/arch/arm/isa/insts/data64.isa')
-rw-r--r-- | src/arch/arm/isa/insts/data64.isa | 13 |
1 files changed, 1 insertions, 12 deletions
diff --git a/src/arch/arm/isa/insts/data64.isa b/src/arch/arm/isa/insts/data64.isa index 48fc87ccb..3284d5b2a 100644 --- a/src/arch/arm/isa/insts/data64.isa +++ b/src/arch/arm/isa/insts/data64.isa @@ -248,18 +248,7 @@ let {{ Dest64 = (Op164 == 0) ? intWidth : (intWidth - 1 - findMsbSet(Op164)); ''') buildDataXRegInst("rbit", 1, ''' - uint64_t result = Op164; - uint64_t lBit = 1ULL << (intWidth - 1); - uint64_t rBit = 1ULL; - while (lBit > rBit) { - uint64_t maskBits = lBit | rBit; - uint64_t testBits = result & maskBits; - // If these bits are different, swap them by toggling them. - if (testBits && testBits != maskBits) - result ^= maskBits; - lBit >>= 1; rBit <<= 1; - } - Dest64 = result; + Dest64 = reverseBits(Op164, intWidth/8); ''') buildDataXRegInst("rev", 1, ''' if (intWidth == 32) |