target-i386: Check CR4[DE] for processing DR4/DR5

Introduce helper_get_dr so that we don't have to put CR4[DE]
into the scarce HFLAGS resource.  At the same time, rename
helper_movl_drN_T0 to helper_set_dr and set the helper flags.

Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

1 files changed, 41 insertions, 5 deletions

diff --git a/target-i386/bpt_helper.c b/target-i386/bpt_helper.c
index 117cea2564..144cfd43fc 100644
--- a/target-i386/bpt_helper.c
+++ b/target-i386/bpt_helper.c
@@ -242,10 +242,11 @@ void helper_single_step(CPUX86State *env)
     raise_exception(env, EXCP01_DB);
 }
 
-void helper_movl_drN_T0(CPUX86State *env, int reg, target_ulong t0)
+void helper_set_dr(CPUX86State *env, int reg, target_ulong t0)
 {
 #ifndef CONFIG_USER_ONLY
-    if (reg < 4) {
+    switch (reg) {
+    case 0: case 1: case 2: case 3:
         if (hw_breakpoint_enabled(env->dr[7], reg)
             && hw_breakpoint_type(env->dr[7], reg) != DR7_TYPE_IO_RW) {
             hw_breakpoint_remove(env, reg);
@@ -254,14 +255,49 @@ void helper_movl_drN_T0(CPUX86State *env, int reg, target_ulong t0)
         } else {
             env->dr[reg] = t0;
         }
-    } else if (reg == 7) {
+        return;
+    case 4:
+        if (env->cr[4] & CR4_DE_MASK) {
+            break;
+        }
+        /* fallthru */
+    case 6:
+        env->dr[6] = t0;
+        return;
+    case 5:
+        if (env->cr[4] & CR4_DE_MASK) {
+            break;
+        }
+        /* fallthru */
+    case 7:
         cpu_x86_update_dr7(env, t0);
-    } else {
-        env->dr[reg] = t0;
+        return;
     }
+    raise_exception_err_ra(env, EXCP06_ILLOP, 0, GETPC());
 #endif
 }
 
+target_ulong helper_get_dr(CPUX86State *env, int reg)
+{
+    switch (reg) {
+    case 0: case 1: case 2: case 3: case 6: case 7:
+        return env->dr[reg];
+    case 4:
+        if (env->cr[4] & CR4_DE_MASK) {
+            break;
+        } else {
+            return env->dr[6];
+        }
+    case 5:
+        if (env->cr[4] & CR4_DE_MASK) {
+            break;
+        } else {
+            return env->dr[7];
+        }
+    }
+    raise_exception_err_ra(env, EXCP06_ILLOP, 0, GETPC());
+}
+
 /* Check if Port I/O is trapped by a breakpoint.  */
 void helper_bpt_io(CPUX86State *env, uint32_t port,
                    uint32_t size, target_ulong next_eip)