Changeset 103885 in vbox for trunk/src/VBox/VMM/VMMAll

Timestamp:

Mar 18, 2024 10:19:33 AM (9 months ago)

Author:

vboxsync

Message:

VMM/IEM: Used the cached offBuf in the first memcpy case. Make sure we only read some other variables once as well. bugref:10370

File:

• trunk/src/VBox/VMM/VMMAll/IEMAll.cpp (modified) (1 diff)

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

@@ -857 +857 @@
          * rest simpler.  This is the first part of the cross page/buffer case.
          */
-        if (pVCpu->iem.s.pbInstrBuf != NULL)
+        uint8_t const * const pbInstrBuf = pVCpu->iem.s.pbInstrBuf;
+        if (pbInstrBuf != NULL)
         {
             Assert(cbDst != 0); /* pbInstrBuf shall be NULL in case of a TLB load */
-            if (offBuf < pVCpu->iem.s.cbInstrBuf)
+            uint32_t const cbInstrBuf = pVCpu->iem.s.cbInstrBuf;
+            if (offBuf < cbInstrBuf)
             {
-                Assert(offBuf + cbDst > pVCpu->iem.s.cbInstrBuf);
-                uint32_t const cbCopy = pVCpu->iem.s.cbInstrBuf - pVCpu->iem.s.offInstrNextByte;
-                memcpy(pvDst, &pVCpu->iem.s.pbInstrBuf[offBuf], cbCopy);
+                Assert(offBuf + cbDst > cbInstrBuf);
+                uint32_t const cbCopy = cbInstrBuf - offBuf;
+                memcpy(pvDst, &pbInstrBuf[offBuf], cbCopy);
 
                 cbDst  -= cbCopy;