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-sta...@nongnu.org
Reported-by: Claudio Fontana <cfont...@suse.de>
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 <i...@linux.ibm.com>
---
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 9b85becdfbf..a19f429768f 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;
}
}
--
2.41.0
