Changeset 105318 in vbox for trunk/src/VBox/VMM/include/IEMN8veRecompilerEmit.h

Timestamp:

Jul 13, 2024 12:53:36 AM (5 months ago)

Author:

vboxsync

Message:

VMM/IEM: Tweak for really large TLBs; save an instruction on ARM64 and'ing with 32-bit constants that aren't more than 16 bits wide; update the iemNativeHlpCheckTlbLookup code and made it work on ARM64. bugref:10687

File:

• trunk/src/VBox/VMM/include/IEMN8veRecompilerEmit.h (modified) (2 diffs)

trunk/src/VBox/VMM/include/IEMN8veRecompilerEmit.h

@@ -5024 +5024 @@
     else if (iGprDst != iGprSrc)
     {
+        /* If a value greater or equal than 64K isn't more than 16 bits wide,
+           we can use shifting to save an instruction.  We prefer the builtin ctz
+           here to our own, since the compiler can process uImm at compile time
+           if it is a constant value (which is often the case).  This is useful
+           for the TLB looup code. */
+        if (uImm > 0xffffU)
+        {
+#  if defined(__GNUC__)
+            unsigned cTrailingZeros = __builtin_ctz(uImm);
+#  else
+            unsigned cTrailingZeros = ASMBitFirstSetU32(uImm) - 1;
+#  endif
+            if ((uImm >> cTrailingZeros) <= 0xffffU)
+            {
+                pCodeBuf[off++] = Armv8A64MkInstrMovZ(iGprDst, uImm >> cTrailingZeros);
+                pCodeBuf[off++] = Armv8A64MkInstrAnd(iGprDst, iGprSrc,
+                                                     iGprDst, true /*f64Bit*/, cTrailingZeros, kArmv8A64InstrShift_Lsl);
+                return off;
+            }
+        }
         off = iemNativeEmitLoadGpr32ImmEx(pCodeBuf, off, iGprDst, uImm);
         off = iemNativeEmitAndGpr32ByGpr32Ex(pCodeBuf, off, iGprDst, iGprSrc, fSetFlags);
@@ -7881 +7901 @@
  * Emits a call to a 64-bit address.
  */
+DECL_FORCE_INLINE(uint32_t) iemNativeEmitCallImmEx(PIEMNATIVEINSTR pCodeBuf, uint32_t off, uintptr_t uPfn,
+#ifdef RT_ARCH_AMD64
+                                                   uint8_t idxRegTmp = X86_GREG_xAX
+#elif defined(RT_ARCH_ARM64)
+                                                   uint8_t idxRegTmp = IEMNATIVE_REG_FIXED_TMP0
+#else
+# error "Port me"
+#endif
+                                                   )
+{
+    off = iemNativeEmitLoadGprImmEx(pCodeBuf, off, idxRegTmp, uPfn);
+
+#ifdef RT_ARCH_AMD64
+    /* call idxRegTmp */
+    if (idxRegTmp >= 8)
+        pCodeBuf[off++] = X86_OP_REX_B;
+    pCodeBuf[off++] = 0xff;
+    pCodeBuf[off++] = X86_MODRM_MAKE(X86_MOD_REG, 2, idxRegTmp & 7);
+
+#elif defined(RT_ARCH_ARM64)
+    pCodeBuf[off++] = Armv8A64MkInstrBlr(idxRegTmp);
+
+#else
+# error "port me"
+#endif
+    return off;
+}
+
+
+/**
+ * Emits a call to a 64-bit address.
+ */
 DECL_INLINE_THROW(uint32_t) iemNativeEmitCallImm(PIEMRECOMPILERSTATE pReNative, uint32_t off, uintptr_t uPfn)
 {