diff --git a/src/system/boot/arch/x86/cpu.cpp b/src/system/boot/arch/x86/cpu.cpp
index 9389fe042b..91f2ae9337 100644
--- a/src/system/boot/arch/x86/cpu.cpp
+++ b/src/system/boot/arch/x86/cpu.cpp
@@ -23,8 +23,6 @@
 #include <string.h>
 
 
-extern "C" uint64 rdtsc();
-
 uint32 gTimeConversionFactor;
 
 // PIT definitions
@@ -66,6 +64,17 @@ uint32 gTimeConversionFactor;
 	// TODO: These are arbitrary. They are here to avoid spinning indefinitely
 	// if the TSC just isn't stable and we can't get our desired error range.
 
+#if __GNUC__ <= 2
+// It's a builtin on later compiler versions, but not in gcc2...
+static inline uint64_t __rdtsc()
+{
+	uint64 tsc;
+
+	asm volatile ("rdtsc\n" : "=A"(tsc));
+
+	return tsc;
+}
+#endif
 
 struct uint128 {
 	uint128(uint64 low, uint64 high = 0)
@@ -198,7 +207,7 @@ calibration_loop(uint8 desiredHighByte, uint8 channel, uint64& tscDelta,
 	} while (startHigh != 255);
 
 	// Read in the first TSC value
-	uint64 startTSC = rdtsc();
+	uint64 startTSC = __rdtsc();
 
 	// Wait for the PIT to count down to our desired value
 	uint8 endLow;
@@ -210,7 +219,7 @@ calibration_loop(uint8 desiredHighByte, uint8 channel, uint64& tscDelta,
 	} while (endHigh > desiredHighByte);
 
 	// And read the second TSC value
-	uint64 endTSC = rdtsc();
+	uint64 endTSC = __rdtsc();
 
 	tscDelta = endTSC - startTSC;
 	expired = ((startHigh << 8) | startLow) - ((endHigh << 8) | endLow);
@@ -304,7 +313,7 @@ slower_sample:
 extern "C" bigtime_t
 system_time()
 {
-	uint64 tsc = rdtsc();
+	uint64 tsc = __rdtsc();
 	uint64 lo = (uint32)tsc;
 	uint64 hi = tsc >> 32;
 	return ((lo * gTimeConversionFactor) >> 32) + hi * gTimeConversionFactor;
diff --git a/src/system/boot/platform/bios_ia32/debug.cpp b/src/system/boot/platform/bios_ia32/debug.cpp
index 9bbc6dc708..4fc67738ac 100644
--- a/src/system/boot/platform/bios_ia32/debug.cpp
+++ b/src/system/boot/platform/bios_ia32/debug.cpp
@@ -32,11 +32,6 @@ static ring_buffer* sDebugSyslogBuffer = NULL;
 static bool sPostCleanup = false;
 
 
-#ifdef PRINT_TIME_STAMPS
-extern "C" uint64 rdtsc();
-#endif
-
-
 static void
 syslog_write(const char* buffer, size_t length)
 {
@@ -65,7 +60,7 @@ dprintf_args(const char *format, va_list args)
 
 	if (sNewLine) {
 		char timeBuffer[32];
-		snprintf(timeBuffer, sizeof(timeBuffer), "[%" B_PRIu64 "] ", rdtsc());
+		snprintf(timeBuffer, sizeof(timeBuffer), "[%" B_PRIu64 "] ", __rdtsc());
 		syslog_write(timeBuffer, strlen(timeBuffer));
 		serial_puts(timeBuffer, strlen(timeBuffer));
 	}
diff --git a/src/system/boot/platform/bios_ia32/support.S b/src/system/boot/platform/bios_ia32/support.S
index ce89d6d892..442b72dcb5 100644
--- a/src/system/boot/platform/bios_ia32/support.S
+++ b/src/system/boot/platform/bios_ia32/support.S
@@ -7,11 +7,6 @@
 #define FUNCTION(x) .global x; .type x,@function; x
 
 
-/* uint64 rdtsc() */
-FUNCTION(rdtsc):
-	rdtsc
-	ret
-
 FUNCTION(execute_n_instructions):
 	movl	4(%esp), %ecx
 	shrl	$4, %ecx
diff --git a/src/system/boot/platform/efi/support.S b/src/system/boot/platform/efi/support.S
index 81828472d6..4c77461fae 100644
--- a/src/system/boot/platform/efi/support.S
+++ b/src/system/boot/platform/efi/support.S
@@ -7,14 +7,6 @@
 #define FUNCTION(x) .global x; .type x,@function; x
 
 
-/* uint64 rdtsc() */
-FUNCTION(rdtsc):
-	rdtsc
-	/* Convert to 64-bit result in rax. */
-	shlq    $32, %rdx
-	orq     %rdx, %rax
-	ret
-
 FUNCTION(execute_n_instructions):
 	movl	%edi, %ecx
 	shrl	$4, %ecx