start implementing APIC utils

src/utils/utils.c

@@ -57,3 +57,27 @@ uint32_t fat32_datetime(uint16_t year, uint8_t month, uint8_t day, uint8_t hour,
 
 	return fat_datetime;
 }
+
+inline void cpuid(int code, uint32_t *a, uint32_t *d)
+{
+	asm volatile("cpuid":"=a"(*a),"=d"(*d):"a"(code):"ecx","ebx");
+}
+
+const uint32_t CPUID_FLAG_MSR = 1 << 5;
+
+bool cpuHasMSR()
+{
+   static uint32_t a, d; // eax, edx
+   cpuid(1, &a, &d);
+   return d & CPUID_FLAG_MSR;
+}
+
+void cpuGetMSR(uint32_t msr, uint32_t *lo, uint32_t *hi)
+{
+   asm volatile("rdmsr" : "=a"(*lo), "=d"(*hi) : "c"(msr));
+}
+
+void cpuSetMSR(uint32_t msr, uint32_t lo, uint32_t hi)
+{
+   asm volatile("wrmsr" : : "a"(lo), "d"(hi), "c"(msr));
+}