Changeset 62408 in vbox for trunk/src/VBox/VMM/VMMAll

Timestamp:

Jul 21, 2016 8:23:33 PM (8 years ago)

Author:

vboxsync

Message:

iemAImpl_imul_u64: Adjusted flag behavior to match that of Intel Skylake 6700K.

File:

• trunk/src/VBox/VMM/VMMAll/IEMAllAImplC.cpp (modified) (3 diffs)

trunk/src/VBox/VMM/VMMAll/IEMAllAImplC.cpp

@@ -1148 +1148 @@
 IEM_DECL_IMPL_DEF(int, iemAImpl_imul_u64,(uint64_t *pu64RAX, uint64_t *pu64RDX, uint64_t u64Factor, uint32_t *pfEFlags))
 {
-/** @todo Testcase: IMUL 1 operand   */
     RTUINT128U Result;
-    *pfEFlags &= ~(X86_EFL_SF | X86_EFL_CF | X86_EFL_OF);
+    *pfEFlags &= ~( X86_EFL_SF | X86_EFL_CF | X86_EFL_OF
+                   /* Skylake always clears: */ | X86_EFL_AF | X86_EFL_ZF
+                   /* Skylake may set: */       | X86_EFL_PF);
+
     if ((int64_t)*pu64RAX >= 0)
     {
@@ -1184 +1186 @@
     }
     *pu64RAX = Result.s.Lo;
+    if (Result.s.Lo & RT_BIT_64(63))
+        *pfEFlags |= X86_EFL_SF;
+    *pfEFlags |= g_afParity[Result.s.Lo & 0xff]; /* (Skylake behaviour) */
     *pu64RDX = Result.s.Hi;
-    if (*pu64RAX & RT_BIT_64(63))
-        *pfEFlags |= X86_EFL_SF;
-
-    /** @todo research the undefined IMUL flags. */
+
     return 0;
 }
@@ -1238 +1240 @@
 IEM_DECL_IMPL_DEF(int, iemAImpl_idiv_u64,(uint64_t *pu64RAX, uint64_t *pu64RDX, uint64_t u64Divisor, uint32_t *pfEFlags))
 {
+    /* Note! Skylake leaves all flags alone. */
     if (u64Divisor != 0)
     {