Fix AMD cores count (#42)

Author: 9il

source/cpuid/amd.d

@@ -211,6 +211,7 @@ union LeafExt8Information
             uint CLZERO();
             /// Instructions retired count support
             uint IRPerf();
+            ///
             uint XSaveErPtr();
             /// Number of threads in the package - 1
             uint NC();
@@ -233,9 +234,9 @@ union LeafExt8Information
 
             /// EBX
             mixin(bitfields!(
-                uint, "CLZERO", 1,
-                uint, "IRPerf", 1,
-                uint, "XSaveErPtr", 1,
+                bool, "CLZERO", 1,
+                bool, "IRPerf", 1,
+                bool, "XSaveErPtr", 1,
                 uint, "", 31 - 3 + 1,
             ));
 
@@ -251,6 +252,55 @@ union LeafExt8Information
     }
 }
 
+/++
+Extended APIC ID.
+
+Core Identifiers.
+
+Node Identifiers.
+
+Specification: AMD
++/
+union LeafExt1EInformation
+{
+    /// CPUID payload
+    CpuInfo info;
+
+    ///
+    struct
+    {
+        import mir.bitmanip: bitfields;
+        // EAX
+        /// Extended APIC ID
+        uint ExtendedApicId;
+        // EBX
+        ushort __reserved__EBX;
+        /// The number of threads per core is ThreadsPerCore+1.
+        ubyte ThreadsPerCore;
+        /// Core ID
+        ubyte CoreId;
+        version(D_Ddoc)
+        {
+        const @trusted @property pure nothrow @nogc:
+            ///  Node per processor.
+            uint NodesPerProcessor();
+            /// Node ID
+            uint NodeId();
+        }
+        else
+        {
+        @trusted @property pure nothrow @nogc:
+
+            /// ECX
+            mixin(bitfields!(
+                uint, "", 31 - 11 + 1,
+                uint, "NodesPerProcessor", 10 - 8 + 1,
+                uint, "NodeId", 7 - 0 + 1,
+            ));
+        }
+    }
+}
+
 /++
 Decodes Associativity Fields for L2/L3 Cache or TLB.
 `T.max` is used to represent full-associative Cache/TLB.

source/cpuid/unified.d

@@ -109,11 +109,12 @@ void mir_cpuid_init()
     static import cpuid.amd;
 
     /// for old CPUs
-    _threads._mut = _cores._mut = maxLogicalProcessors;
     if(htt)
     {
-        _threads._mut *= 2;
+        _threads._mut = _cores._mut = maxLogicalProcessors;
+        _cores._mut /= 2;
     }
+
     if (vendorIndex == VendorIndex.amd || 
         vendorIndex == VendorIndex.amd_old || 
         vendorIndex == VendorIndex.centaur || 
@@ -196,6 +197,12 @@ void mir_cpuid_init()
                 {
                     auto leafExt8 = cpuid.amd.LeafExt8Information(_cpuid(0x8000_0008));
                     _threads._mut = leafExt8.NC + 1;
+
+                    if (maxExtendedLeaf >= 0x8000_001E)
+                    {
+                        auto leafExt1E = cpuid.amd.LeafExt1EInformation(_cpuid(0x8000_001E));
+                        _cores._mut = _threads / (leafExt1E.ThreadsPerCore + 1);
+                    }
                 }
             }
         }