target/s390x: implement UNPACK ASCII

Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Message-Id: <20170531220129.27724-26-aurelien@aurel32.net>
Signed-off-by: Richard Henderson <rth@twiddle.net>

target/s390x/helper.h

@@ -89,6 +89,7 @@ DEF_HELPER_FLAGS_4(pack, TCG_CALL_NO_WG, void, env, i32, i64, i64)
 DEF_HELPER_FLAGS_4(pka, TCG_CALL_NO_WG, void, env, i64, i64, i32)
 DEF_HELPER_FLAGS_4(pku, TCG_CALL_NO_WG, void, env, i64, i64, i32)
 DEF_HELPER_FLAGS_4(unpk, TCG_CALL_NO_WG, void, env, i32, i64, i64)
+DEF_HELPER_FLAGS_4(unpka, TCG_CALL_NO_WG, i32, env, i64, i32, i64)
 DEF_HELPER_FLAGS_4(tr, TCG_CALL_NO_WG, void, env, i32, i64, i64)
 DEF_HELPER_4(tre, i64, env, i64, i64, i64)
 DEF_HELPER_4(trt, i32, env, i32, i64, i64)

target/s390x/insn-data.def

@@ -871,6 +871,8 @@
     /* Really format SS_b, but we pack both lengths into one argument
        for the helper call, so we might as well leave one 8-bit field.  */
     C(0xf300, UNPK,    SS_a,  Z,   la1, a2, 0, 0, unpk, 0)
+/* UNPACK ASCII */
+    C(0xea00, UNPKA,   SS_a,  E2,  la1, a2, 0, 0, unpka, 0)
 
 #ifndef CONFIG_USER_ONLY
 /* COMPARE AND SWAP AND PURGE */

target/s390x/mem_helper.c

@@ -1008,6 +1008,57 @@ void HELPER(unpk)(CPUS390XState *env, uint32_t len, uint64_t dest,
     }
 }
 
+uint32_t HELPER(unpka)(CPUS390XState *env, uint64_t dest, uint32_t destlen,
+                       uint64_t src)
+{
+    uintptr_t ra = GETPC();
+    int i;
+    uint32_t cc;
+    uint8_t b;
+    /* The source operand is always 16 bytes long.  */
+    const int srclen = 16;
+
+    /* The operands are processed from right to left.  */
+    src += srclen - 1;
+    dest += destlen - 1;
+
+    /* Check for the sign.  */
+    b = cpu_ldub_data_ra(env, src, ra);
+    src--;
+    switch (b & 0xf) {
+    case 0xa:
+    case 0xc:
+    case 0xe ... 0xf:
+        cc = 0;  /* plus */
+        break;
+    case 0xb:
+    case 0xd:
+        cc = 1;  /* minus */
+        break;
+    default:
+    case 0x0 ... 0x9:
+        cc = 3;  /* invalid */
+        break;
+    }
+
+    /* Now pad every nibble with 0x30, advancing one nibble at a time. */
+    for (i = 0; i < destlen; i++) {
+        if (i == 31) {
+            /* If length is 32 bytes, the leftmost byte is 0. */
+            b = 0;
+        } else if (i % 2) {
+            b = cpu_ldub_data_ra(env, src, ra);
+            src--;
+        } else {
+            b >>= 4;
+        }
+        cpu_stb_data_ra(env, dest, 0x30 + (b & 0xf), ra);
+        dest--;
+    }
+
+    return cc;
+}
+
 static uint32_t do_helper_tr(CPUS390XState *env, uint32_t len, uint64_t array,
                              uint64_t trans, uintptr_t ra)
 {

target/s390x/translate.c

@@ -4349,6 +4349,23 @@ static ExitStatus op_unpk(DisasContext *s, DisasOps *o)
     return NO_EXIT;
 }
 
+static ExitStatus op_unpka(DisasContext *s, DisasOps *o)
+{
+    int l1 = get_field(s->fields, l1) + 1;
+    TCGv_i32 l;
+
+    /* The length must not exceed 32 bytes.  */
+    if (l1 > 32) {
+        gen_program_exception(s, PGM_SPECIFICATION);
+        return EXIT_NORETURN;
+    }
+    l = tcg_const_i32(l1);
+    gen_helper_unpka(cc_op, cpu_env, o->addr1, l, o->in2);
+    tcg_temp_free_i32(l);
+    set_cc_static(s);
+    return NO_EXIT;
+}
+
 static ExitStatus op_xc(DisasContext *s, DisasOps *o)
 {
     int d1 = get_field(s->fields, d1);