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| author | Björn Gustavsson <[email protected]> | 2017-04-07 12:04:11 +0200 |
|---|---|---|
| committer | Björn Gustavsson <[email protected]> | 2017-04-07 12:08:08 +0200 |
| commit | bb89d065dbe47554c0cb929d244e0d38cad52e65 (patch) | |
| tree | 429feea4650430532ad23210de981ced039bc289 | |
| parent | 90aacace4bdb1c883c3829bc66c1c616a81943d9 (diff) | |
| download | otp-bb89d065dbe47554c0cb929d244e0d38cad52e65.tar.gz otp-bb89d065dbe47554c0cb929d244e0d38cad52e65.tar.bz2 otp-bb89d065dbe47554c0cb929d244e0d38cad52e65.zip | |
beam_emu: Slightly optimize the bxor/2 operator
bxor is used in the rand module, so even small optimizations
could be worthwile.
Suggested by Raimo Niskanen.
| -rw-r--r-- | erts/emulator/beam/beam_emu.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c index 9a91fdce08..6010c17c17 100644 --- a/erts/emulator/beam/beam_emu.c +++ b/erts/emulator/beam/beam_emu.c @@ -3044,10 +3044,12 @@ do { \ GetArg2(2, Op1, Op2); if (is_both_small(Op1, Op2)) { /* - * We could extract the tag from one argument, but a tag extraction - * could mean a shift. Therefore, play it safe here. + * TAG ^ TAG == 0. + * + * Therefore, we perform the XOR operation on the tagged values, + * and OR in the tag bits. */ - Eterm result = make_small(signed_val(Op1) ^ signed_val(Op2)); + Eterm result = (Op1 ^ Op2) | make_small(0); StoreBifResult(4, result); } DO_OUTLINED_ARITH_2(bxor, Op1, Op2); |