added most_significant_bit* methods to scalar_arith.h

bochs-emu · Nov 23, 2023 · 1cfd97e · 1cfd97e
1 parent 32c7c38
commit 1cfd97e
Showing 1 changed file with 15 additions and 0 deletions.
diff --git a/bochs/cpu/scalar_arith.h b/bochs/cpu/scalar_arith.h
@@ -87,6 +87,11 @@ BX_CPP_INLINE unsigned lzcntw(Bit16u val_16)
   return count;
 }
 
+BX_CPP_INLINE unsigned most_significant_bitw(Bit16u val_16)
+{
+  return 15 - lzcntw(val_16);
+}
+
 BX_CPP_INLINE unsigned lzcntd(Bit32u val_32)
 {
   Bit32u mask = 0x80000000;
@@ -100,6 +105,11 @@ BX_CPP_INLINE unsigned lzcntd(Bit32u val_32)
   return count;
 }
 
+BX_CPP_INLINE unsigned most_significant_bitd(Bit32u val_32)
+{
+  return 31 - lzcntd(val_32);
+}
+
 BX_CPP_INLINE unsigned lzcntq(Bit64u val_64)
 {
   Bit64u mask = BX_CONST64(0x8000000000000000);
@@ -113,6 +123,11 @@ BX_CPP_INLINE unsigned lzcntq(Bit64u val_64)
   return count;
 }
 
+BX_CPP_INLINE unsigned most_significant_bitq(Bit64u val_64)
+{
+  return 63 - lzcntq(val_64);
+}
+
 // popcnt
 
 BX_CPP_INLINE unsigned popcntb(Bit8u val_8)