Changeset 103828 in vbox for trunk/src/VBox/VMM/VMMAll/target-x86

Timestamp:

Mar 13, 2024 2:01:20 PM (11 months ago)

Author:

vboxsync

Message:

VMM/IEM: Implemented simple (whole sale) status flag up update skipping for arithmetic operations with native emitter. bugref:10375

File:

• trunk/src/VBox/VMM/VMMAll/target-x86/IEMAllN8veEmit-x86.h (modified) (4 diffs)

trunk/src/VBox/VMM/VMMAll/target-x86/IEMAllN8veEmit-x86.h

@@ -207 +207 @@
                               )
 {
-#ifdef IEMNATIVE_WITH_LIVENESS_ANALYSIS
-    if (1) /** @todo check if all bits are clobbered. */
+#ifdef IEMNATIVE_WITH_EFLAGS_SKIPPING
+    /** @todo */
 #endif
     {
@@ -276 +276 @@
 #endif
         IEMNATIVE_ASSERT_INSTR_BUF_ENSURE(pReNative, off);
+
+#  ifdef IEMNATIVE_STRICT_EFLAGS_SKIPPING
+        off = iemNativeEmitStoreImmToVCpuU32(pReNative, off, 0, RT_UOFFSETOF(VMCPU, iem.s.fSkippingEFlags));
+#  endif
     }
     return off;
@@ -294 +298 @@
                                  )
 {
-#ifdef IEMNATIVE_WITH_LIVENESS_ANALYSIS
-    if (1) /** @todo check if all bits are clobbered. */
-#endif
-    {
+#ifdef IEMNATIVE_WITH_EFLAGS_SKIPPING
+    /*
+     * See if we can skip this wholesale.
+     */
+    PCIEMLIVENESSENTRY const pLivenessEntry = &pReNative->paLivenessEntries[pReNative->idxCurCall];
+    if (IEMLIVENESS_STATE_ARE_STATUS_EFL_TO_BE_CLOBBERED(pLivenessEntry))
+    {
+        STAM_COUNTER_INC(&pReNative->pVCpu->iem.s.StatNativeEflArithmeticSkipped);
+# ifdef IEMNATIVE_STRICT_EFLAGS_SKIPPING
+        off = iemNativeEmitOrImmIntoVCpuU32(pReNative, off, X86_EFL_STATUS_BITS, RT_UOFFSETOF(VMCPU, iem.s.fSkippingEFlags));
+# endif
+    }
+    else
+#endif
+    {
+#ifdef IEMNATIVE_STRICT_EFLAGS_SKIPPING
+        uint32_t fSkipped = 0;
+#endif
 #ifdef RT_ARCH_AMD64
         /*
@@ -446 +464 @@
             iemNativeVarRegisterRelease(pReNative, idxVarEfl);
         iemNativeRegFreeTmp(pReNative, idxTmpReg);
+
 #else
 # error "port me"
 #endif
         IEMNATIVE_ASSERT_INSTR_BUF_ENSURE(pReNative, off);
+
+#ifdef IEMNATIVE_STRICT_EFLAGS_SKIPPING
+        off = iemNativeEmitStoreImmToVCpuU32(pReNative, off, fSkipped, RT_UOFFSETOF(VMCPU, iem.s.fSkippingEFlags));
+#endif
     }
     return off;