diff --git a/Core/gb.c b/Core/gb.c
index bf41891..cc86fef 100755
--- a/Core/gb.c
+++ b/Core/gb.c
@@ -271,15 +271,17 @@ exit:
     return;
 }
 
-void GB_run(GB_gameboy_t *gb)
+uint8_t GB_run(GB_gameboy_t *gb)
 {
     GB_debugger_run(gb);
+    gb->cycles_since_run = 0;
     GB_cpu_run(gb);
     if (gb->vblank_just_occured) {
         GB_update_joyp(gb);
         GB_rtc_run(gb);
         GB_debugger_handle_async_commands(gb);
     }
+    return gb->cycles_since_run;
 }
 
 uint64_t GB_run_frame(GB_gameboy_t *gb)
diff --git a/Core/gb.h b/Core/gb.h
index dbe81ed..ca373f5 100644
--- a/Core/gb.h
+++ b/Core/gb.h
@@ -483,6 +483,7 @@ struct GB_gameboy_internal_s {
         uint32_t ram_size; // Different between CGB and DMG
         uint8_t boot_rom[0x900];
         bool vblank_just_occured; // For slow operations involving syscalls; these should only run once per vblank
+        uint8_t cycles_since_run; // How many cycles have passed since the last call to GB_run()
    );
 };
     
@@ -506,7 +507,9 @@ bool GB_is_cgb(GB_gameboy_t *gb);
 void GB_free(GB_gameboy_t *gb);
 void GB_reset(GB_gameboy_t *gb);
 void GB_switch_model_and_reset(GB_gameboy_t *gb, bool is_cgb);
-void GB_run(GB_gameboy_t *gb);
+
+/* Returns the time passed, in 4MHz ticks. */
+uint8_t GB_run(GB_gameboy_t *gb);
 /* Returns the time passed since the last frame, in nanoseconds */
 uint64_t GB_run_frame(GB_gameboy_t *gb);
 
diff --git a/Core/timing.c b/Core/timing.c
index 1818a7c..cbcfb82 100644
--- a/Core/timing.c
+++ b/Core/timing.c
@@ -153,6 +153,7 @@ void GB_advance_cycles(GB_gameboy_t *gb, uint8_t cycles)
     gb->cycles_since_ir_change += cycles;
     gb->cycles_since_input_ir_change += cycles;
     gb->cycles_since_last_sync += cycles;
+    gb->cycles_since_run += cycles;
     GB_dma_run(gb);
     GB_hdma_run(gb);
     GB_apu_run(gb);