Detect CPUID instruction before using it.

[seabios.git] / src / util.c

diff --git a/src/util.c b/src/util.c
index ed73d632f11e619d1e83fbba7d7c581f82adc481..53ef84ded96dfb230c3162b4bafded88fa3394cf 100644 (file)
--- a/src/util.c
+++ b/src/util.c
@@ -8,6 +8,22 @@
 #include "bregs.h" // struct bregs
 #include "config.h" // BUILD_STACK_ADDR
 
+void
+cpuid(u32 index, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx)
+{
+    // Check for cpu id
+    u32 origflags = save_flags();
+    restore_flags(origflags ^ F_ID);
+    u32 newflags = save_flags();
+    restore_flags(origflags);
+
+    if (((origflags ^ newflags) & F_ID) != F_ID)
+        // no cpuid
+        *eax = *ebx = *ecx = *edx = 0;
+    else
+        __cpuid(index, eax, ebx, ecx, edx);
+}
+
 
 /****************************************************************
  * 16bit calls