Testing physics

src/dusklinux/system/systemlinux.c

@@ -7,10 +7,30 @@
 
 #include "systemlinux.h"
 
+#if defined(__x86_64__) || defined(__i386__)
+  #include <x86intrin.h>
+#else
+  #include <time.h>
+#endif
+
 errorret_t systemInitLinux() {
   errorOk();
 }
 
 systemdialogtype_t systemGetActiveDialogTypeLinux() {
   return SYSTEM_DIALOG_TYPE_NONE;
+}
+
+uint64_t systemGetCyclesLinux(void) {
+  #if defined(__x86_64__) || defined(__i386__)
+    return __rdtsc();
+  #elif defined(__aarch64__)
+    uint64_t cycles;
+    __asm__ volatile("mrs %0, cntvct_el0" : "=r" (cycles));
+    return cycles;
+  #else
+    struct timespec ts;
+    clock_gettime(CLOCK_MONOTONIC, &ts);
+    return (uint64_t)ts.tv_sec * 1000000000ULL + (uint64_t)ts.tv_nsec;
+  #endif
 }

src/dusklinux/system/systemlinux.h

@@ -15,7 +15,16 @@ errorret_t systemInitLinux(void);
 
 /**
  * Currently just returns SYSTEM_DIALOG_TYPE_NONE.
- * 
+ *
  * @return Currently open system dialog type.
  */
-systemdialogtype_t systemGetActiveDialogTypeLinux();
+systemdialogtype_t systemGetActiveDialogTypeLinux();
+
+/**
+ * Returns the current CPU cycle counter value. Uses the hardware
+ * timestamp counter on x86/x86_64 and the virtual counter register on
+ * ARM64, falling back to a monotonic nanosecond clock elsewhere.
+ *
+ * @return The current CPU cycle count.
+ */
+uint64_t systemGetCyclesLinux(void);

src/dusklinux/system/systemplatform.h

@@ -9,4 +9,5 @@
 #include "system/systemlinux.h"
 
 #define systemInitPlatform systemInitLinux
-#define systemGetActiveDialogTypePlatform systemGetActiveDialogTypeLinux
+#define systemGetActiveDialogTypePlatform systemGetActiveDialogTypeLinux
+#define systemGetCyclesPlatform systemGetCyclesLinux