From f443b5808e7225f570530a377ae6efd6972ce536 Mon Sep 17 00:00:00 2001 From: Sverker Eriksson Date: Fri, 2 Dec 2011 18:03:24 +0100 Subject: erts: Fix bug in large big/float compare Bug caused faulty result (big_SUITE:big_float_1) and an unhandled floating point exception. --- erts/emulator/beam/utils.c | 39 ++++++++++++++------------------------- 1 file changed, 14 insertions(+), 25 deletions(-) (limited to 'erts/emulator/beam') diff --git a/erts/emulator/beam/utils.c b/erts/emulator/beam/utils.c index df03f5e42c..4105f194a9 100644 --- a/erts/emulator/beam/utils.c +++ b/erts/emulator/beam/utils.c @@ -2661,6 +2661,7 @@ tailrecur_ne: #endif #define MAX_LOSSLESS_FLOAT ((double)((1LL << 53) - 2)) #define MIN_LOSSLESS_FLOAT ((double)(((1LL << 53) - 2)*-1)) +#define BIG_ARITY_FLOAT_MAX (1024 / D_EXP) /* arity of max float as a bignum */ b_tag = tag_val_def(bw); switch(_NUMBER_CODE(a_tag, b_tag)) { @@ -2693,16 +2694,24 @@ tailrecur_ne: } #endif // ERTS_SIZEOF_ETERM == 8 break; + case FLOAT_BIG: + { + Wterm tmp = aw; + aw = bw; + bw = tmp; + }/* fall through */ case BIG_FLOAT: GET_DOUBLE(bw, f2); if ((f2.fd < (double) (MAX_SMALL + 1)) && (f2.fd > (double) (MIN_SMALL - 1))) { // Float is a Sint j = big_sign(aw) ? -1 : 1; - } else if ((pow(2.0,(big_arity(aw)-1.0)*D_EXP)-1.0) > fabs(f2.fd)) { + } else if (big_arity(aw) > BIG_ARITY_FLOAT_MAX + || pow(2.0,(big_arity(aw)-1)*D_EXP) > fabs(f2.fd)) { // If bignum size shows that it is bigger than the abs float j = big_sign(aw) ? -1 : 1; - } else if ((pow(2.0,(big_arity(aw))*D_EXP)-1.0) < fabs(f2.fd)) { + } else if (big_arity(aw) < BIG_ARITY_FLOAT_MAX + && (pow(2.0,(big_arity(aw))*D_EXP)-1.0) < fabs(f2.fd)) { // If bignum size shows that it is smaller than the abs float j = f2.fd < 0 ? 1 : -1; } else if (f2.fd < MAX_LOSSLESS_FLOAT && f2.fd > MIN_LOSSLESS_FLOAT) { @@ -2716,6 +2725,9 @@ tailrecur_ne: big = double_to_big(f2.fd, big_buf); j = big_comp(aw, big); } + if (_NUMBER_CODE(a_tag, b_tag) == FLOAT_BIG) { + j = -j; + } break; case FLOAT_SMALL: GET_DOUBLE(aw, f1); @@ -2740,29 +2752,6 @@ tailrecur_ne: } #endif // ERTS_SIZEOF_ETERM == 8 break; - case FLOAT_BIG: - GET_DOUBLE(aw, f1); - if ((f1.fd < (double) (MAX_SMALL + 1)) - && (f1.fd > (double) (MIN_SMALL - 1))) { // Float is a Sint - j = big_sign(bw) ? 1 : -1; - } else if ((pow(2.0, (big_arity(bw) - 1.0) * D_EXP) - 1.0) > fabs(f1.fd)) { - // If bignum size shows that it is bigger than the abs float - j = big_sign(bw) ? 1 : -1; - } else if ((pow(2.0,(big_arity(bw))*D_EXP)-1.0) < fabs(f1.fd)) { - // If bignum size shows that it is smaller than the abs float - j = f1.fd < 0 ? -1 : 1; - } else if (f1.fd < MAX_LOSSLESS_FLOAT && f1.fd > MIN_LOSSLESS_FLOAT) { - // Float is within the no loss limit - if (big_to_double(bw, &f2.fd) < 0) { - j = big_sign(bw) ? 1 : -1; - } else { - j = float_comp(f1.fd, f2.fd); - } - } else { - big = double_to_big(f1.fd, big_buf); - j = big_comp(big, bw); - } - break; default: j = b_tag - a_tag; } -- cgit v1.2.3