target/arm: Split out vfp_expand_imm

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20180110063337.21538-2-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 28 insertions, 16 deletions

diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
index ba94f7d045..80ae019172 100644
--- a/target/arm/translate-a64.c
+++ b/target/arm/translate-a64.c
@@ -4985,6 +4985,33 @@ static void disas_fp_3src(DisasContext *s, uint32_t insn)
     }
 }
 
+/* The imm8 encodes the sign bit, enough bits to represent an exponent in
+ * the range 01....1xx to 10....0xx, and the most significant 4 bits of
+ * the mantissa; see VFPExpandImm() in the v8 ARM ARM.
+ */
+static uint64_t vfp_expand_imm(int size, uint8_t imm8)
+{
+    uint64_t imm;
+
+    switch (size) {
+    case MO_64:
+        imm = (extract32(imm8, 7, 1) ? 0x8000 : 0) |
+            (extract32(imm8, 6, 1) ? 0x3fc0 : 0x4000) |
+            extract32(imm8, 0, 6);
+        imm <<= 48;
+        break;
+    case MO_32:
+        imm = (extract32(imm8, 7, 1) ? 0x8000 : 0) |
+            (extract32(imm8, 6, 1) ? 0x3e00 : 0x4000) |
+            (extract32(imm8, 0, 6) << 3);
+        imm <<= 16;
+        break;
+    default:
+        g_assert_not_reached();
+    }
+    return imm;
+}
+
 /* Floating point immediate
  *   31  30  29 28       24 23  22  21 20        13 12   10 9    5 4    0
  * +---+---+---+-----------+------+---+------------+-------+------+------+
@@ -5008,22 +5035,7 @@ static void disas_fp_imm(DisasContext *s, uint32_t insn)
         return;
     }
 
-    /* The imm8 encodes the sign bit, enough bits to represent
-     * an exponent in the range 01....1xx to 10....0xx,
-     * and the most significant 4 bits of the mantissa; see
-     * VFPExpandImm() in the v8 ARM ARM.
-     */
-    if (is_double) {
-        imm = (extract32(imm8, 7, 1) ? 0x8000 : 0) |
-            (extract32(imm8, 6, 1) ? 0x3fc0 : 0x4000) |
-            extract32(imm8, 0, 6);
-        imm <<= 48;
-    } else {
-        imm = (extract32(imm8, 7, 1) ? 0x8000 : 0) |
-            (extract32(imm8, 6, 1) ? 0x3e00 : 0x4000) |
-            (extract32(imm8, 0, 6) << 3);
-        imm <<= 16;
-    }
+    imm = vfp_expand_imm(MO_32 + is_double, imm8);
 
     tcg_res = tcg_const_i64(imm);
     write_fp_dreg(s, rd, tcg_res);