4 files changed, 44 insertions, 31 deletions

diff --git a/target-s390x/helper.h b/target-s390x/helper.h
index 999d5d0604..dd7479abcf 100644
--- a/target-s390x/helper.h
+++ b/target-s390x/helper.h
@@ -13,7 +13,7 @@ DEF_HELPER_3(divs32, s64, env, s64, s64)
 DEF_HELPER_3(divu32, i64, env, i64, i64)
 DEF_HELPER_3(divs64, s64, env, s64, s64)
 DEF_HELPER_4(divu64, i64, env, i64, i64, i64)
-DEF_HELPER_4(srst, i32, env, i32, i32, i32)
+DEF_HELPER_4(srst, i64, env, i64, i64, i64)
 DEF_HELPER_4(clst, i64, env, i64, i64, i64)
 DEF_HELPER_4(mvpg, void, env, i64, i64, i64)
 DEF_HELPER_4(mvst, i64, env, i64, i64, i64)
diff --git a/target-s390x/insn-data.def b/target-s390x/insn-data.def
index b485b85e9c..5e1f8fda9b 100644
--- a/target-s390x/insn-data.def
+++ b/target-s390x/insn-data.def
@@ -471,6 +471,9 @@
     C(0xeb1d, RLL,     RSY_a, Z,   r3_o, sh32, new, r1_32, rll32, 0)
     C(0xeb1c, RLLG,    RSY_a, Z,   r3_o, sh64, r1, 0, rll64, 0)
 
+/* SEARCH STRING */
+    C(0xb25e, SRST,    RRE,   Z,   r1_o, r2_o, 0, 0, srst, 0)
+
 /* SET ACCESS */
     C(0xb24e, SAR,     RRE,   Z,   0, r2_o, 0, 0, sar, 0)
 /* SET FPC */
diff --git a/target-s390x/mem_helper.c b/target-s390x/mem_helper.c
index 7d87c746f6..59877eef96 100644
--- a/target-s390x/mem_helper.c
+++ b/target-s390x/mem_helper.c
@@ -331,25 +331,38 @@ static inline uint64_t get_address_31fix(CPUS390XState *env, int reg)
 }
 
 /* search string (c is byte to search, r2 is string, r1 end of string) */
-uint32_t HELPER(srst)(CPUS390XState *env, uint32_t c, uint32_t r1, uint32_t r2)
+uint64_t HELPER(srst)(CPUS390XState *env, uint64_t r0, uint64_t end,
+                      uint64_t str)
 {
-    uint64_t i;
-    uint32_t cc = 2;
-    uint64_t str = get_address_31fix(env, r2);
-    uint64_t end = get_address_31fix(env, r1);
+    uint32_t len;
+    uint8_t v, c = r0;
 
-    HELPER_LOG("%s: c %d *r1 0x%" PRIx64 " *r2 0x%" PRIx64 "\n", __func__,
-               c, env->regs[r1], env->regs[r2]);
+    str = fix_address(env, str);
+    end = fix_address(env, end);
 
-    for (i = str; i != end; i++) {
-        if (cpu_ldub_data(env, i) == c) {
-            env->regs[r1] = i;
-            cc = 1;
-            break;
+    /* Assume for now that R2 is unmodified.  */
+    env->retxl = str;
+
+    /* Lest we fail to service interrupts in a timely manner, limit the
+       amount of work we're willing to do.  For now, lets cap at 8k.  */
+    for (len = 0; len < 0x2000; ++len) {
+        if (str + len == end) {
+            /* Character not found.  R1 & R2 are unmodified.  */
+            env->cc_op = 2;
+            return end;
+        }
+        v = cpu_ldub_data(env, str + len);
+        if (v == c) {
+            /* Character found.  Set R1 to the location; R2 is unmodified.  */
+            env->cc_op = 1;
+            return str + len;
         }
     }
 
-    return cc;
+    /* CPU-determined bytes processed.  Advance R2 to next byte to process.  */
+    env->retxl = str + len;
+    env->cc_op = 3;
+    return end;
 }
 
 /* unsigned string compare (c is string terminator) */
diff --git a/target-s390x/translate.c b/target-s390x/translate.c
index f1eb4bb8da..bbbd5fe09a 100644
--- a/target-s390x/translate.c
+++ b/target-s390x/translate.c
@@ -1021,12 +1021,11 @@ static void free_compare(DisasCompare *c)
 static void disas_b2(CPUS390XState *env, DisasContext *s, int op,
                      uint32_t insn)
 {
+#ifndef CONFIG_USER_ONLY
     TCGv_i64 tmp, tmp2, tmp3;
-    TCGv_i32 tmp32_1, tmp32_2, tmp32_3;
+    TCGv_i32 tmp32_1, tmp32_2;
     int r1, r2;
-#ifndef CONFIG_USER_ONLY
     int r3, d2, b2;
-#endif
 
     r1 = (insn >> 4) & 0xf;
     r2 = insn & 0xf;
@@ -1034,19 +1033,6 @@ static void disas_b2(CPUS390XState *env, DisasContext *s, int op,
     LOG_DISAS("disas_b2: op 0x%x r1 %d r2 %d\n", op, r1, r2);
 
     switch (op) {
-    case 0x5e: /* SRST     R1,R2     [RRE] */
-        tmp32_1 = load_reg32(0);
-        tmp32_2 = tcg_const_i32(r1);
-        tmp32_3 = tcg_const_i32(r2);
-        potential_page_fault(s);
-        gen_helper_srst(cc_op, cpu_env, tmp32_1, tmp32_2, tmp32_3);
-        set_cc_static(s);
-        tcg_temp_free_i32(tmp32_1);
-        tcg_temp_free_i32(tmp32_2);
-        tcg_temp_free_i32(tmp32_3);
-        break;
-
-#ifndef CONFIG_USER_ONLY
     case 0x02: /* STIDP     D2(B2)     [S] */
         /* Store CPU ID */
         check_privileged(s);
@@ -1314,12 +1300,14 @@ static void disas_b2(CPUS390XState *env, DisasContext *s, int op,
         tcg_temp_free_i32(tmp32_1);
         tcg_temp_free_i64(tmp);
         break;
-#endif
     default:
+#endif
         LOG_DISAS("illegal b2 operation 0x%x\n", op);
         gen_illegal_opcode(s);
+#ifndef CONFIG_USER_ONLY
         break;
     }
+#endif
 }
 
 static void disas_s390_insn(CPUS390XState *env, DisasContext *s)
@@ -3136,6 +3124,15 @@ static ExitStatus op_stmh(DisasContext *s, DisasOps *o)
     return NO_EXIT;
 }
 
+static ExitStatus op_srst(DisasContext *s, DisasOps *o)
+{
+    potential_page_fault(s);
+    gen_helper_srst(o->in1, cpu_env, regs[0], o->in1, o->in2);
+    set_cc_static(s);
+    return_low128(o->in2);
+    return NO_EXIT;
+}
+
 static ExitStatus op_sub(DisasContext *s, DisasOps *o)
 {
     tcg_gen_sub_i64(o->out, o->in1, o->in2);