From 5980189e960ead2ee84c0c8053302ebfe982617f Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Sat, 5 Aug 2023 01:03:18 +0200 Subject: [PATCH] target/s390x: Fix the "ignored match" case in VSTRS Currently the emulation of VSTRS recognizes partial matches in presence of \0 in the haystack, which, according to PoP, is not correct: If the ZS flag is one and a zero byte was detected in the second operand, then there can not be a partial match ... Add a check for this. While at it, fold a number of explicitly handled special cases into the generic logic. Cc: qemu-stable@nongnu.org Reported-by: Claudio Fontana Closes: https://lists.gnu.org/archive/html/qemu-devel/2023-08/msg00633.html Fixes: 1d706f314191 ("target/s390x: vxeh2: vector string search") Signed-off-by: Ilya Leoshkevich Message-Id: <20230804233748.218935-3-iii@linux.ibm.com> Tested-by: Claudio Fontana Acked-by: David Hildenbrand Signed-off-by: Thomas Huth (cherry picked from commit 791b2b6a930273db694b9ba48bbb406e78715927) Signed-off-by: Michael Tokarev --- target/s390x/tcg/vec_string_helper.c | 54 +++++++++------------------- 1 file changed, 17 insertions(+), 37 deletions(-) diff --git a/target/s390x/tcg/vec_string_helper.c b/target/s390x/tcg/vec_string_helper.c index 9b85becdfb..a19f429768 100644 --- a/target/s390x/tcg/vec_string_helper.c +++ b/target/s390x/tcg/vec_string_helper.c @@ -474,9 +474,9 @@ DEF_VSTRC_CC_RT_HELPER(32) static int vstrs(S390Vector *v1, const S390Vector *v2, const S390Vector *v3, const S390Vector *v4, uint8_t es, bool zs) { - int substr_elen, substr_0, str_elen, i, j, k, cc; + int substr_elen, i, j, k, cc; int nelem = 16 >> es; - bool eos = false; + int str_leftmost_0; substr_elen = s390_vec_read_element8(v4, 7) >> es; @@ -498,47 +498,20 @@ static int vstrs(S390Vector *v1, const S390Vector *v2, const S390Vector *v3, } /* If ZS, look for eos in the searched string. */ + str_leftmost_0 = nelem; if (zs) { for (k = 0; k < nelem; k++) { if (s390_vec_read_element(v2, k, es) == 0) { - eos = true; + str_leftmost_0 = k; break; } } - str_elen = k; - } else { - str_elen = nelem; } - substr_0 = s390_vec_read_element(v3, 0, es); - - for (k = 0; ; k++) { - for (; k < str_elen; k++) { - if (s390_vec_read_element(v2, k, es) == substr_0) { - break; - } - } - - /* If we reached the end of the string, no match. */ - if (k == str_elen) { - cc = eos; /* no match (with or without zero char) */ - goto done; - } - - /* If the substring is only one char, match. */ - if (substr_elen == 1) { - cc = 2; /* full match */ - goto done; - } - - /* If the match begins at the last char, we have a partial match. */ - if (k == str_elen - 1) { - cc = 3; /* partial match */ - goto done; - } - + cc = str_leftmost_0 == nelem ? 0 : 1; /* No match. */ + for (k = 0; k < nelem; k++) { i = MIN(nelem, k + substr_elen); - for (j = k + 1; j < i; j++) { + for (j = k; j < i; j++) { uint32_t e2 = s390_vec_read_element(v2, j, es); uint32_t e3 = s390_vec_read_element(v3, j - k, es); if (e2 != e3) { @@ -546,9 +519,16 @@ static int vstrs(S390Vector *v1, const S390Vector *v2, const S390Vector *v3, } } if (j == i) { - /* Matched up until "end". */ - cc = i - k == substr_elen ? 2 : 3; /* full or partial match */ - goto done; + /* All elements matched. */ + if (k > str_leftmost_0) { + cc = 1; /* Ignored match. */ + k = nelem; + } else if (i - k == substr_elen) { + cc = 2; /* Full match. */ + } else { + cc = 3; /* Partial match. */ + } + break; } }