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-rw-r--r--erts/emulator/test/big_SUITE.erl39
1 files changed, 37 insertions, 2 deletions
diff --git a/erts/emulator/test/big_SUITE.erl b/erts/emulator/test/big_SUITE.erl
index c308760211..b25868d3cb 100644
--- a/erts/emulator/test/big_SUITE.erl
+++ b/erts/emulator/test/big_SUITE.erl
@@ -24,7 +24,7 @@
-export([t_div/1, eq_28/1, eq_32/1, eq_big/1, eq_math/1, big_literals/1,
borders/1, negative/1, big_float_1/1, big_float_2/1,
- bxor_2pow/1,
+ bxor_2pow/1, band_2pow/1,
shift_limit_1/1, powmod/1, system_limit/1, toobig/1, otp_6692/1]).
%% Internal exports.
@@ -43,7 +43,7 @@ suite() ->
all() ->
[t_div, eq_28, eq_32, eq_big, eq_math, big_literals,
borders, negative, {group, big_float}, shift_limit_1,
- bxor_2pow,
+ bxor_2pow, band_2pow,
powmod, system_limit, toobig, otp_6692].
groups() ->
@@ -449,3 +449,38 @@ my_bxor(A, B, N, Acc0) ->
false -> Acc0 bor (1 bsl N)
end,
my_bxor(A bsr 1, B bsr 1, N+1, Acc1).
+
+
+%% ERL-804
+band_2pow(_Config) ->
+ IL = lists:seq(8*3, 8*16, 4),
+ JL = lists:seq(0, 64),
+ [band_2pow_1((1 bsl I), (1 bsl J))
+ || I <- IL, J <- JL],
+ ok.
+
+band_2pow_1(A, B) ->
+ for(-1,1, fun(Ad) ->
+ for(-1,1, fun(Bd) ->
+ band_2pow_2(A+Ad, B+Bd),
+ band_2pow_2(-A+Ad, B+Bd),
+ band_2pow_2(A+Ad, -B+Bd),
+ band_2pow_2(-A+Ad, -B+Bd)
+ end)
+ end).
+
+band_2pow_2(A, B) ->
+ Correct = my_band(A, B),
+ case A band B of
+ Correct -> ok;
+ Wrong ->
+ io:format("~.16# band ~.16#\n", [A,B]),
+ io:format("Expected ~.16#\n", [Correct]),
+ io:format("Got ~.16#\n", [Wrong]),
+ ct:fail({failed, 'band'})
+
+ end.
+
+%% Implement band without band
+my_band(A, B) ->
+ bnot ((bnot A) bor (bnot B)).