diff --git a/include/rp6502.h b/include/rp6502.h
index 2b40cfc71..61664c78f 100644
--- a/include/rp6502.h
+++ b/include/rp6502.h
@@ -101,6 +101,7 @@ long __fastcall__ ria_call_long_errno (unsigned char op);
 #define RIA_OP_CODEPAGE 0x03
 #define RIA_OP_LRAND 0x04
 #define RIA_OP_STDIN_OPT 0x05
+#define RIA_OP_CLOCK 0x0F
 #define RIA_OP_CLOCK_GETRES 0x10
 #define RIA_OP_CLOCK_GETTIME 0x11
 #define RIA_OP_CLOCK_SETTIME 0x12
diff --git a/include/time.h b/include/time.h
index f8977ab0c..5eb6f144a 100644
--- a/include/time.h
+++ b/include/time.h
@@ -86,6 +86,8 @@ struct tm {
 #  define CLOCKS_PER_SEC        135   /* FIXME */
 #elif defined(__GEOS__)
 #  define CLOCKS_PER_SEC        1
+#elif defined (__RP6502__)
+#  define CLOCKS_PER_SEC        100
 #elif defined(__TELESTRAT__)
 #  define CLOCKS_PER_SEC        10
 #elif defined(__ATARI__) || defined (__LYNX__)
diff --git a/libsrc/rp6502/clock.c b/libsrc/rp6502/clock.c
new file mode 100644
index 000000000..f8756f553
--- /dev/null
+++ b/libsrc/rp6502/clock.c
@@ -0,0 +1,7 @@
+#include <rp6502.h>
+#include <time.h>
+
+clock_t __fastcall__ clock (void)
+{
+    return ria_call_long (RIA_OP_CLOCK);
+}