target-arm: A64: add support for ADR and ADRP

Add support for the instructions described in
"C3.4.6 PC-rel. addressing" (ADR and ADRP).
Signed-off-by: NAlexander Graf <agraf@suse.de>
[claudio: adapted to new decoder structure]
Signed-off-by: NClaudio Fontana <claudio.fontana@linaro.org>
Reviewed-by: NRichard Henderson <rth@twiddle.net>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

target-arm/translate-a64.c

@@ -653,10 +653,31 @@ static void disas_ldst(DisasContext *s, uint32_t insn)
     }
 }
 
-/* PC-rel. addressing */
+/* C3.4.6 PC-rel. addressing
+ *   31  30   29 28       24 23                5 4    0
+ * +----+-------+-----------+-------------------+------+
+ * | op | immlo | 1 0 0 0 0 |       immhi       |  Rd  |
+ * +----+-------+-----------+-------------------+------+
+ */
 static void disas_pc_rel_adr(DisasContext *s, uint32_t insn)
 {
-    unsupported_encoding(s, insn);
+    unsigned int page, rd;
+    uint64_t base;
+    int64_t offset;
+
+    page = extract32(insn, 31, 1);
+    /* SignExtend(immhi:immlo) -> offset */
+    offset = ((int64_t)sextract32(insn, 5, 19) << 2) | extract32(insn, 29, 2);
+    rd = extract32(insn, 0, 5);
+    base = s->pc - 4;
+
+    if (page) {
+        /* ADRP (page based) */
+        base &= ~0xfff;
+        offset <<= 12;
+    }
+
+    tcg_gen_movi_i64(cpu_reg(s, rd), base + offset);
 }
 
 /* Add/subtract (immediate) */