test

2026-07-20 01:53:04 +02:00
commit e71245c082
149 changed files with 8571 additions and 0 deletions
@@ -0,0 +1,54 @@
+#include <zinnia/clock.h>
+#include <zinnia/cmdline.h>
+#include <zinnia/print.h>
+#include <x86_64/asm.h>
+#include <x86_64/defs.h>
+
+static bool use_tsc = true;
+
+void tsc_init() {
+    if (!use_tsc)
+        return;
+
+    if (!(asm_cpuid(1, 0).edx & CPUID_1D_TSC) || !(asm_cpuid(0x8000'0007, 0).edx & (1 << 8))) {
+        printf("No invariant TSC detected!\n");
+        return;
+    }
+
+    // Check for the TSC info leaf.
+    bool has_tsc_leaf = false;
+    struct cpuid tsc_leaf = {0};
+    if (asm_cpuid(0x8000'0000, 0).eax >= 0x15) {
+        tsc_leaf = asm_cpuid(0x15, 0);
+    }
+
+    uint64_t freq = 0;
+    if (clock_available()) {
+        // Calibrate using existing clock.
+        uint64_t t1 = asm_rdtsc();
+        clock_spin_ns(10'000'000);
+        uint64_t t2 = asm_rdtsc();
+        freq = (t2 - t1) * 100;
+    } else if (has_tsc_leaf) {
+        // If we have no timer (yet), the only way we can calibrate the TSC is if CPUID gives us the frequency.
+        // On a normal system, this should usually never be called and is a last resort
+        // since at this point we have at least the HPET timer.
+        if (tsc_leaf.ecx != 0 && tsc_leaf.ebx != 0 && tsc_leaf.eax != 0) {
+            printf("Calibrating TSC using CPUID 0x15");
+            freq = tsc_leaf.ecx * tsc_leaf.ebx / tsc_leaf.eax;
+        } else {
+            printf("Unable to calibrate TSC using CPUID frequency information");
+            return;
+        }
+    } else {
+        printf("Unable to calibrate the TSC without a clock or static frequency info!\n");
+        return;
+    }
+
+    printf("Timer frequency is %lu MHz\n", freq / 1'000'000);
+}
+
+static void tsc_option(bool opt) {
+    use_tsc = opt;
+}
+CMDLINE_OPTION("tsc", tsc_option);