diff --git a/src/6502.c b/src/6502.c
index 7d50ed72..c971eb2a 100644
--- a/src/6502.c
+++ b/src/6502.c
@@ -226,6 +226,7 @@ int output = 0;
 static int timetolive = 0;
 
 int cycles;
+uint64_t stopwatch;
 static int otherstuffcount = 0;
 int romsel;
 
@@ -237,6 +238,7 @@ static void polltime(int c)
     video_poll(c, 1);
     sound_poll(c);
     music5000_poll(c);
+    stopwatch += c;
     otherstuffcount -= c;
     if (motoron) {
         if (fdc_time) {
@@ -1032,6 +1034,7 @@ void m6502_reset(void)
         nmi = oldnmi = 0;
         output = 0;
         tubecycle = tubecycles = 0;
+        stopwatch = 0;
         log_debug("PC : %04X\n", pc);
 }
 
diff --git a/src/6502.h b/src/6502.h
index 5c94c1b5..2a4d890c 100644
--- a/src/6502.h
+++ b/src/6502.h
@@ -5,7 +5,6 @@
 
 extern uint8_t a,x,y,s;
 extern uint16_t pc;
-extern uint_least32_t cycles_6502;
 
 extern PREG p;
 
@@ -23,6 +22,7 @@ extern int interrupt;
  */
 extern int nmi;
 
+extern uint64_t stopwatch;
 extern int romsel;
 extern uint8_t ram1k, ram4k, ram8k;
 
diff --git a/src/debugger.c b/src/debugger.c
index 0742e595..46a05c1b 100644
--- a/src/debugger.c
+++ b/src/debugger.c
@@ -75,6 +75,9 @@ static int contcount = 0;
 
 static const char time_fmt[] = "%d/%m/%Y %H:%M:%S";
 
+static uint64_t user_stopwatches[] = { ~0, ~0, ~0, ~0, ~0, ~0, ~0, ~0, ~0, ~0 };
+static const int user_stopwatch_count = sizeof(user_stopwatches)/sizeof(*user_stopwatches);
+
 static void close_trace(const char *why)
 {
     if (trace_fp) {
@@ -394,6 +397,9 @@ void debug_reset()
         fprintf(trace_fp, "Processor reset at %s\n", when);
         fflush(trace_fp);
     }
+    for (int i=0; i<user_stopwatch_count; i++) {
+        user_stopwatches[i] = ~0;
+    }
 }
 
 static const char helptext[] =
@@ -429,6 +435,7 @@ static const char helptext[] =
     "    ruler [s [c]] - draw a ruler to help with hexdumps.\n"
     "                 starts at 's' for 'c' bytes\n"
     "    s [n]      - step n instructions (or 1 if no parameter)\n"
+    "    swatch [n] - start/clear/print stopwatches\n"
     "    symbol name=[rom:]addr\n"
     "               - add debugger symbol\n"
     "    symlist    - list all symbols\n"
@@ -765,6 +772,41 @@ static void debugger_save(cpu_debug_t *cpu, char *iptr)
         debug_outf("Nothing to save (no breakpoints)\n");
 }
 
+static void debugger_stopwatch(cpu_debug_t *cpu, const char* iptr)
+{
+    if (*iptr) {
+        int user = atoi(iptr);
+        if (user >= 0 && user < user_stopwatch_count) {
+            if (user_stopwatches[user] < ~0) {
+                user_stopwatches[user] = ~0;
+                debug_outf("User stopwatch %d cleared.\n", user);
+            }
+            else {
+                user_stopwatches[user] = stopwatch;
+                debug_outf("User stopwatch %d started.\n", user);
+            }
+        }
+        else {
+            debug_outf("User stopwatches IDs must be in the range 0 to %d.\n",
+                user_stopwatch_count-1);
+        }
+    }
+    else {
+        debug_outf("%" PRIu64 " cycles since reset (%.3f s)\n", stopwatch, (double)stopwatch / 2000000.0);
+        if (stopwatch_vblank) {
+            uint64_t delta = stopwatch - stopwatch_vblank;
+            debug_outf("%" PRIu64 " cycles since vertical blank (%.3f s)\n", delta, (double)delta / 2000000.0);
+        }
+        for (int i=0; i<user_stopwatch_count; i++) {
+            if (user_stopwatches[i] < ~0) {
+                uint64_t delta = stopwatch - user_stopwatches[i];
+                debug_outf("%" PRIu64 " cycles since user stopwatch %d (%.3f s)\n",
+                    delta, i, (double)delta / 2000000.0);
+            }
+        }
+    }
+}
+
 void trimnl(char *buf) {
     int len = strlen(buf);
 
@@ -1516,6 +1558,8 @@ void debugger_do(cpu_debug_t *cpu, uint32_t addr)
                         else
                             debug_outf("Missing filename\n");
                     }
+                    else if (!strncmp(cmd, "swatch", cmdlen))
+                        debugger_stopwatch(cpu, iptr);
                     else
                         badcmd = true;
                     break;
diff --git a/src/video.c b/src/video.c
index aab8f3f3..82f01224 100644
--- a/src/video.c
+++ b/src/video.c
@@ -7,6 +7,7 @@
 #include "b-em.h"
 
 #include "config.h"
+#include "6502.h"
 #include "mem.h"
 #include "model.h"
 #include "serial.h"
@@ -41,10 +42,13 @@ static enum {
     CRTC_LOFREQ
 } crtc_mode;
 
+uint64_t stopwatch_vblank;
+
 void crtc_reset()
 {
     hc = vc = sc = vadj = 0;
     crtc[9] = 10;
+    stopwatch_vblank = 0;
 }
 
 static void set_intern_dtype(enum vid_disptype dtype)
@@ -1123,8 +1127,9 @@ void video_poll(int clocks, int timer_enable)
         }
         if (hvblcount) {
             hvblcount--;
-            if (!hvblcount && timer_enable)
+            if (!hvblcount && timer_enable) {
                 sysvia_set_ca1(0);
+            }
         }
 
         if (interline && hc == (crtc[0] >> 1)) {
@@ -1237,8 +1242,10 @@ void video_poll(int clocks, int timer_enable)
                     if (ccount == 10 || ((!motor || !fasttape) && !is_free_run()))
                         ccount = 0;
                     scry = 0;
-                    if (timer_enable)
+                    if (timer_enable) {
+                        stopwatch_vblank = stopwatch;
                         sysvia_set_ca1(1);
+                    }
 
                     vsynctime = (crtc[3] >> 4) + 1;
                     if (!(crtc[3] >> 4))
diff --git a/src/video.h b/src/video.h
index 3f772c1e..b919bb4d 100644
--- a/src/video.h
+++ b/src/video.h
@@ -17,6 +17,7 @@ extern int crtc_i;
 
 extern int hc, vc, sc;
 extern uint16_t ma;
+extern uint64_t stopwatch_vblank;
 
 /*Video ULA (VIDPROC)*/
 void videoula_write(uint16_t addr, uint8_t val);