From b22ffa589145234d23d07602752dacf9f30b4e4c Mon Sep 17 00:00:00 2001 From: Piotr Caban Date: Thu, 23 Jul 2020 15:38:37 +0200 Subject: [PATCH] msvcrt: Don't depend on additional mantissa bits when rounding. Signed-off-by: Piotr Caban Signed-off-by: Alexandre Julliard --- dlls/msvcrt/string.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/dlls/msvcrt/string.c b/dlls/msvcrt/string.c index a2ec9a91acb..802ae5f0af3 100644 --- a/dlls/msvcrt/string.c +++ b/dlls/msvcrt/string.c @@ -831,12 +831,17 @@ struct fpnum fpnum_parse(MSVCRT_wchar_t (*get)(void *ctx), void (*unget)(void *c e2++; } - /* Check if fractional part is non-zero */ - /* Caution: it's only correct because bnum_to_mant returns more than 53 bits */ - for(i=b->e-4; i>=b->b; i--) { - if (!b->data[bnum_idx(b, b->b)]) continue; - round = FP_ROUND_DOWN; - break; + if(b->e-4 >= b->b && b->data[bnum_idx(b, b->e-4)]) { + if(b->data[bnum_idx(b, b->e-4)] > LIMB_MAX/2) round = FP_ROUND_UP; + else if(b->data[bnum_idx(b, b->e-4)] == LIMB_MAX/2) round = FP_ROUND_EVEN; + else round = FP_ROUND_DOWN; + } + if(round == FP_ROUND_ZERO || round == FP_ROUND_EVEN) { + for(i=b->e-5; i>=b->b; i--) { + if(!b->data[bnum_idx(b, b->b)]) continue; + if(round == FP_ROUND_EVEN) round = FP_ROUND_UP; + else round = FP_ROUND_DOWN; + } } return fpnum(sign, e2, m, round);