diff --git a/common/copy.hpp b/common/copy.hpp
index 4df90fc..d9c1274 100644
--- a/common/copy.hpp
+++ b/common/copy.hpp
@@ -8,3 +8,12 @@ inline void copy(T * dst, const T * src, int32_t n) noexcept
     n -= (sizeof (T));
   }
 }
+
+template <typename T>
+inline void fill(T * dst, const T src, int32_t n) noexcept
+{
+  while (n > 0) {
+    *dst++ = src;
+    n -= (sizeof (T));
+  }
+}
diff --git a/scsp/sound_cpu__interrupt.cpp b/scsp/sound_cpu__interrupt.cpp
index 1cdc707..bccae66 100644
--- a/scsp/sound_cpu__interrupt.cpp
+++ b/scsp/sound_cpu__interrupt.cpp
@@ -15,23 +15,26 @@ void main()
      The document suggests that Sound RAM is (somewhat) preserved
      during SNDOFF.
    */
-  
+
   while ((smpc.reg.SF & 1) != 0);
   smpc.reg.SF = 1;
   smpc.reg.COMREG = COMREG__SNDOFF;
   while (smpc.reg.oreg[31] != OREG31__SNDOFF);
 
   scsp.reg.ctrl.MIXER = MIXER__MEM4MB;
-  
+
+  reg32 * dsp_steps = reinterpret_cast<reg32*>(&(scsp.reg.dsp.STEP[0].MPRO[0]));
+  fill<reg32>(dsp_steps, 0, (sizeof (scsp.reg.dsp.STEP)));
+
   uint32_t * m68k_main_start = reinterpret_cast<uint32_t*>(&_m68k_start);
   uint32_t m68k_main_size = reinterpret_cast<uint32_t>(&_m68k_size);
   copy<uint32_t>(&scsp.ram.u32[0], m68k_main_start, m68k_main_size);
-  
+
   while ((smpc.reg.SF & 1) != 0);
   smpc.reg.SF = 1;
   smpc.reg.COMREG = COMREG__SNDON;
   while (smpc.reg.oreg[31] != OREG31__SNDON);
-  
+
   // do nothing while the sound CPU manipulates the SCSP
 }