[PATCH v3 03/11] target/s390x: vxeh2: vector string search

[Richard Henderson <richard.henderson@linaro.org>]

From: David Miller <dmiller423@gmail.com>

Signed-off-by: David Miller <dmiller423@gmail.com>
Message-Id: <20220307020327.3003-3-dmiller423@gmail.com>
[rth: Rewrite helpers; fix validation of m6.]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---

The substring search was incorrect, in that it didn't properly
restart the search when a match failed.  Split the helper into
multiple, so that the memory accesses can be optimized.
---
 target/s390x/helper.h                |   6 ++
 target/s390x/tcg/translate.c         |   3 +-
 target/s390x/tcg/vec_string_helper.c | 101 +++++++++++++++++++++++++++
 target/s390x/tcg/translate_vx.c.inc  |  26 +++++++
 target/s390x/tcg/insn-data.def       |   2 +
 5 files changed, 137 insertions(+), 1 deletion(-)

diff --git a/target/s390x/helper.h b/target/s390x/helper.h
index 7cbcbd7f0b..7412130883 100644
--- a/target/s390x/helper.h
+++ b/target/s390x/helper.h
@@ -246,6 +246,12 @@ DEF_HELPER_6(gvec_vstrc_cc32, void, ptr, cptr, cptr, cptr, env, i32)
 DEF_HELPER_6(gvec_vstrc_cc_rt8, void, ptr, cptr, cptr, cptr, env, i32)
 DEF_HELPER_6(gvec_vstrc_cc_rt16, void, ptr, cptr, cptr, cptr, env, i32)
 DEF_HELPER_6(gvec_vstrc_cc_rt32, void, ptr, cptr, cptr, cptr, env, i32)
+DEF_HELPER_6(gvec_vstrs_8, void, ptr, cptr, cptr, cptr, env, i32)
+DEF_HELPER_6(gvec_vstrs_16, void, ptr, cptr, cptr, cptr, env, i32)
+DEF_HELPER_6(gvec_vstrs_32, void, ptr, cptr, cptr, cptr, env, i32)
+DEF_HELPER_6(gvec_vstrs_zs8, void, ptr, cptr, cptr, cptr, env, i32)
+DEF_HELPER_6(gvec_vstrs_zs16, void, ptr, cptr, cptr, cptr, env, i32)
+DEF_HELPER_6(gvec_vstrs_zs32, void, ptr, cptr, cptr, cptr, env, i32)
 
 /* === Vector Floating-Point Instructions */
 DEF_HELPER_FLAGS_5(gvec_vfa32, TCG_CALL_NO_WG, void, ptr, cptr, cptr, env, i32)
diff --git a/target/s390x/tcg/translate.c b/target/s390x/tcg/translate.c
index 904b51542f..d9ac29573d 100644
--- a/target/s390x/tcg/translate.c
+++ b/target/s390x/tcg/translate.c
@@ -6222,7 +6222,8 @@ enum DisasInsnEnum {
 #define FAC_PCI         S390_FEAT_ZPCI /* z/PCI facility */
 #define FAC_AIS         S390_FEAT_ADAPTER_INT_SUPPRESSION
 #define FAC_V           S390_FEAT_VECTOR /* vector facility */
-#define FAC_VE          S390_FEAT_VECTOR_ENH /* vector enhancements facility 1 */
+#define FAC_VE          S390_FEAT_VECTOR_ENH  /* vector enhancements facility 1 */
+#define FAC_VE2         S390_FEAT_VECTOR_ENH2 /* vector enhancements facility 2 */
 #define FAC_MIE2        S390_FEAT_MISC_INSTRUCTION_EXT2 /* miscellaneous-instruction-extensions facility 2 */
 #define FAC_MIE3        S390_FEAT_MISC_INSTRUCTION_EXT3 /* miscellaneous-instruction-extensions facility 3 */
 
diff --git a/target/s390x/tcg/vec_string_helper.c b/target/s390x/tcg/vec_string_helper.c
index ac315eb095..6c0476ecc1 100644
--- a/target/s390x/tcg/vec_string_helper.c
+++ b/target/s390x/tcg/vec_string_helper.c
@@ -471,3 +471,104 @@ void HELPER(gvec_vstrc_cc_rt##BITS)(void *v1, const void *v2, const void *v3,  \
 DEF_VSTRC_CC_RT_HELPER(8)
 DEF_VSTRC_CC_RT_HELPER(16)
 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 nelem = 16 >> es;
+    bool eos = false;
+
+    substr_elen = s390_vec_read_element8(v4, 7) >> es;
+
+    /* If ZS, bound substr length by min(nelem, strlen(v3)). */
+    if (zs) {
+        int i;
+        for (i = 0; i < nelem; i++) {
+            if (s390_vec_read_element(v3, i, es) == 0) {
+                break;
+            }
+        }
+        if (i < substr_elen) {
+            substr_elen = i;
+        }
+    }
+
+    if (substr_elen == 0) {
+        cc = 2; /* full match for degenerate case of empty substr */
+        k = 0;
+        goto done;
+    }
+
+    /* If ZS, look for eos in the searched string. */
+    if (zs) {
+        for (k = 0; k < nelem; k++) {
+            if (s390_vec_read_element(v2, k, es) == 0) {
+                eos = true;
+                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;
+        }
+
+        i = MIN(nelem, k + substr_elen);
+        for (j = k + 1; 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) {
+                break;
+            }
+        }
+        if (j == i) {
+            /* Matched up until "end". */
+            cc = i - k == substr_elen ? 2 : 3; /* full or partial match */
+            goto done;
+        }
+    }
+
+ done:
+    s390_vec_write_element64(v1, 0, k << es);
+    s390_vec_write_element64(v1, 1, 0);
+    return cc;
+}
+
+#define DEF_VSTRS_HELPER(BITS)                                             \
+void QEMU_FLATTEN HELPER(gvec_vstrs_##BITS)(void *v1, const void *v2,      \
+    const void *v3, const void *v4, CPUS390XState *env, uint32_t desc)     \
+    { env->cc_op = vstrs(v1, v2, v3, v4, MO_##BITS, false); }              \
+void QEMU_FLATTEN HELPER(gvec_vstrs_zs##BITS)(void *v1, const void *v2,    \
+    const void *v3, const void *v4, CPUS390XState *env, uint32_t desc)     \
+    { env->cc_op = vstrs(v1, v2, v3, v4, MO_##BITS, true); }
+
+DEF_VSTRS_HELPER(8)
+DEF_VSTRS_HELPER(16)
+DEF_VSTRS_HELPER(32)
diff --git a/target/s390x/tcg/translate_vx.c.inc b/target/s390x/tcg/translate_vx.c.inc
index ea28e40d4f..d514e8b218 100644
--- a/target/s390x/tcg/translate_vx.c.inc
+++ b/target/s390x/tcg/translate_vx.c.inc
@@ -2497,6 +2497,32 @@ static DisasJumpType op_vstrc(DisasContext *s, DisasOps *o)
     return DISAS_NEXT;
 }
 
+static DisasJumpType op_vstrs(DisasContext *s, DisasOps *o)
+{
+    typedef void (*helper_vstrs)(TCGv_ptr, TCGv_ptr, TCGv_ptr,
+                                 TCGv_ptr, TCGv_ptr, TCGv_i32);
+    static const helper_vstrs fns[3][2] = {
+        { gen_helper_gvec_vstrs_8, gen_helper_gvec_vstrs_zs8 },
+        { gen_helper_gvec_vstrs_16, gen_helper_gvec_vstrs_zs16 },
+        { gen_helper_gvec_vstrs_32, gen_helper_gvec_vstrs_zs32 },
+    };
+
+    const uint8_t m5 = get_field(s, m5);
+    const uint8_t m6 = get_field(s, m6);
+    bool zs = m6 & 2;
+
+    if (m5 > ES_32 || m6 & ~2) {
+        gen_program_exception(s, PGM_SPECIFICATION);
+        return DISAS_NORETURN;
+    }
+
+    gen_gvec_4_ptr(get_field(s, v1), get_field(s, v2),
+                   get_field(s, v3), get_field(s, v4),
+                   cpu_env, 0, fns[m5][zs]);
+    set_cc_static(s);
+    return DISAS_NEXT;
+}
+
 static DisasJumpType op_vfa(DisasContext *s, DisasOps *o)
 {
     const uint8_t fpf = get_field(s, m4);
diff --git a/target/s390x/tcg/insn-data.def b/target/s390x/tcg/insn-data.def
index 6c8a8b229f..46add91a0e 100644
--- a/target/s390x/tcg/insn-data.def
+++ b/target/s390x/tcg/insn-data.def
@@ -1246,6 +1246,8 @@
     F(0xe75c, VISTR,   VRR_a, V,   0, 0, 0, 0, vistr, 0, IF_VEC)
 /* VECTOR STRING RANGE COMPARE */
     F(0xe78a, VSTRC,   VRR_d, V,   0, 0, 0, 0, vstrc, 0, IF_VEC)
+/* VECTOR STRING SEARCH */
+    F(0xe78b, VSTRS,   VRR_d, VE2, 0, 0, 0, 0, vstrs, 0, IF_VEC)
 
 /* === Vector Floating-Point Instructions */
 
-- 
2.25.1