target-arm: Fix decoding of preload and memory hint space

Correct the decoding of the ARM preload and memory hint space,
by adding decoding of PLI, PLDW and the v7MP unallocated hint
space. This commit also corrects a slightly overexuberant
decoding of PLD(register) which was not checking that bit 4
was one.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

target-arm/translate.c

@@ -6100,9 +6100,31 @@ static void disas_arm_insn(CPUState * env, DisasContext *s)
                 goto illegal_op;
             return;
         }
-        if ((insn & 0x0d70f000) == 0x0550f000)
-            return; /* PLD */
-        else if ((insn & 0x0ffffdff) == 0x01010000) {
+        if (((insn & 0x0f30f000) == 0x0510f000) ||
+            ((insn & 0x0f30f010) == 0x0710f000)) {
+            if ((insn & (1 << 22)) == 0) {
+                /* PLDW; v7MP */
+                if (!arm_feature(env, ARM_FEATURE_V7MP)) {
+                    goto illegal_op;
+                }
+            }
+            /* Otherwise PLD; v5TE+ */
+            return;
+        }
+        if (((insn & 0x0f70f000) == 0x0450f000) ||
+            ((insn & 0x0f70f010) == 0x0650f000)) {
+            ARCH(7);
+            return; /* PLI; V7 */
+        }
+        if (((insn & 0x0f700000) == 0x04100000) ||
+            ((insn & 0x0f700010) == 0x06100000)) {
+            if (!arm_feature(env, ARM_FEATURE_V7MP)) {
+                goto illegal_op;
+            }
+            return; /* v7MP: Unallocated memory hint: must NOP */
+        }
+
+        if ((insn & 0x0ffffdff) == 0x01010000) {
             ARCH(6);
             /* setend */
             if (insn & (1 << 9)) {