Add AMD-specific features to cpuid package

Extend the cpuid package to parse and emulate cpuid features that exist
only on AMD and not Intel. The least straightforward part of this is
that AMD duplicates several block 1 features in block 6. Thus we ignore
those features when parsing block 6 and add them when emulating.

PiperOrigin-RevId: 218935032
Change-Id: Id41bf1c24720b0d9b968e2c19ab5bc00a6d62bd4

1 files changed, 28 insertions, 0 deletions

diff --git a/pkg/cpuid/cpuid_test.go b/pkg/cpuid/cpuid_test.go
index 0decd8f08..35e7b8e50 100644
--- a/pkg/cpuid/cpuid_test.go
+++ b/pkg/cpuid/cpuid_test.go
@@ -18,6 +18,34 @@ import (
 	"testing"
 )
 
+// These are the default values of various FeatureSet fields.
+const (
+	defaultVendorID = "GenuineIntel"
+
+	// These processor signature defaults are derived from the values
+	// listed in Intel Application Note 485 for i7/Xeon processors.
+	defaultExtFamily  uint8 = 0
+	defaultExtModel   uint8 = 1
+	defaultType       uint8 = 0
+	defaultFamily     uint8 = 0x06
+	defaultModel      uint8 = 0x0a
+	defaultSteppingID uint8 = 0
+)
+
+// newEmptyFeatureSet creates a new FeatureSet with a sensible default model and no features.
+func newEmptyFeatureSet() *FeatureSet {
+	return &FeatureSet{
+		Set:            make(map[Feature]bool),
+		VendorID:       defaultVendorID,
+		ExtendedFamily: defaultExtFamily,
+		ExtendedModel:  defaultExtModel,
+		ProcessorType:  defaultType,
+		Family:         defaultFamily,
+		Model:          defaultModel,
+		SteppingID:     defaultSteppingID,
+	}
+}
+
 var justFPU = &FeatureSet{
 	Set: map[Feature]bool{
 		X86FeatureFPU: true,