diff --git a/module_usb_audio/usb_buffer/decouple.xc b/module_usb_audio/usb_buffer/decouple.xc
index edb985e0..0b9869c8 100644
--- a/module_usb_audio/usb_buffer/decouple.xc
+++ b/module_usb_audio/usb_buffer/decouple.xc
@@ -176,7 +176,7 @@ __builtin_unreachable();
                     int mult;
                     int h;
                     unsigned l;
-                    asm("ldw %0, %1[%2]":"=r"(mult):"r"(p_multIn),"r"(i));
+                    asm volatile("ldw %0, %1[%2]":"=r"(mult):"r"(p_multIn),"r"(i));
                     {h, l} = macs(mult, sample, 0, 0);
                     sample = h << 3;
 
@@ -207,7 +207,7 @@ __builtin_unreachable();
                     int mult;
                     int h;
                     unsigned l;
-                    asm("ldw %0, %1[%2]":"=r"(mult):"r"(p_multIn),"r"(i));
+                    asm volatile("ldw %0, %1[%2]":"=r"(mult):"r"(p_multIn),"r"(i));
                     {h, l} = macs(mult, sample, 0, 0);
                     sample = h << 3;
 #if (STREAM_FORMAT_INPUT_RESOLUTION_32BIT_USED == 1)
@@ -240,7 +240,7 @@ __builtin_unreachable();
                     int mult;
                     int h;
                     unsigned l;
-                    asm("ldw %0, %1[%2]":"=r"(mult):"r"(p_multIn),"r"(i));
+                    asm volatile("ldw %0, %1[%2]":"=r"(mult):"r"(p_multIn),"r"(i));
                     {h, l} = macs(mult, sample, 0, 0);
                     sample = h << 3;
 #endif
@@ -343,7 +343,7 @@ __builtin_unreachable();
                     sample <<= 16;
 
 #if (OUTPUT_VOLUME_CONTROL == 1) && !defined(OUT_VOLUME_IN_MIXER)
-                    asm("ldw %0, %1[%2]":"=r"(mult):"r"(p_multOut),"r"(i));
+                    asm volatile("ldw %0, %1[%2]":"=r"(mult):"r"(p_multOut),"r"(i));
                     {h, l} = macs(mult, sample, 0, 0);
                     /* Note, in 2 byte subslot mode - ignore lower result of macs */
                     h <<= 3;
@@ -371,7 +371,7 @@ __builtin_unreachable();
                     g_aud_from_host_rdptr+=4;
 
 #if (OUTPUT_VOLUME_CONTROL == 1) && !defined(OUT_VOLUME_IN_MIXER)
-                    asm("ldw %0, %1[%2]":"=r"(mult):"r"(p_multOut),"r"(i));
+                    asm volatile("ldw %0, %1[%2]":"=r"(mult):"r"(p_multOut),"r"(i));
                     {h, l} = macs(mult, sample, 0, 0);
                     h <<= 3;
 #if (STREAM_FORMAT_OUTPUT_RESOLUTION_32BIT_USED == 1)
@@ -426,7 +426,7 @@ __builtin_unreachable();
                     unpackState++;
 
 #if (OUTPUT_VOLUME_CONTROL == 1) && !defined(OUT_VOLUME_IN_MIXER)
-                    asm("ldw %0, %1[%2]":"=r"(mult):"r"(p_multOut),"r"(i));
+                    asm volatile("ldw %0, %1[%2]":"=r"(mult):"r"(p_multOut),"r"(i));
                     {h, l} = macs(mult, sample, 0, 0);
                     h <<= 3;
                     outuint(c_mix_out, h);
@@ -476,7 +476,7 @@ __builtin_unreachable();
             }
 
             /* Get feedback val - ideally this would be syncronised */
-            asm("ldw   %0, dp[g_speed]" : "=r" (speed) :);
+            asm volatile("ldw   %0, dp[g_speed]" : "=r" (speed) :);
 
             /* Calc packet size to send back based on our fb */
             speedRem += speed;
@@ -587,7 +587,7 @@ static inline void SetupZerosSendBuffer(XUD_ep aud_to_host_usb_ep, unsigned samp
 
     mid *= g_numUsbChan_In * slotSize;
 
-    asm("stw %0, %1[0]"::"r"(mid),"r"(g_aud_to_host_zeros));
+    asm volatile("stw %0, %1[0]"::"r"(mid),"r"(g_aud_to_host_zeros));
 
     /* Mark EP ready with the zero buffer. Note this will simply update the packet size
     * if it is already ready */
@@ -648,14 +648,14 @@ void decouple(chanend c_mix_out
 #ifndef OUT_VOLUME_IN_MIXER
     for (int i = 0; i < NUM_USB_CHAN_OUT + 1; i++)
     {
-        asm("stw %0, %1[%2]"::"r"(MAX_VOL),"r"(p_multOut),"r"(i));
+        asm volatile("stw %0, %1[%2]"::"r"(MAX_VOL),"r"(p_multOut),"r"(i));
     }
 #endif
 
 #ifndef IN_VOLUME_IN_MIXER
     for (int i = 0; i < NUM_USB_CHAN_IN + 1; i++)
     {
-        asm("stw %0, %1[%2]"::"r"(MAX_VOL),"r"(p_multIn),"r"(i));
+        asm volatile("stw %0, %1[%2]"::"r"(MAX_VOL),"r"(p_multIn),"r"(i));
     }
 #endif
 
@@ -751,7 +751,7 @@ void decouple(chanend c_mix_out
                 chkct(c_mix_out, XS1_CT_END);
 
                 SET_SHARED_GLOBAL(g_freqChange, 0);
-                asm("outct res[%0],%1"::"r"(buffer_aud_ctl_chan),"r"(XS1_CT_END));
+                asm volatile("outct res[%0],%1"::"r"(buffer_aud_ctl_chan),"r"(XS1_CT_END));
 
                 ENABLE_INTERRUPTS();
 
@@ -795,7 +795,7 @@ void decouple(chanend c_mix_out
                 }
 
                 SET_SHARED_GLOBAL(g_freqChange, 0);
-                asm("outct res[%0],%1"::"r"(buffer_aud_ctl_chan),"r"(XS1_CT_END));
+                asm volatile("outct res[%0],%1"::"r"(buffer_aud_ctl_chan),"r"(XS1_CT_END));
 
                 ENABLE_INTERRUPTS();
             }
@@ -840,7 +840,7 @@ void decouple(chanend c_mix_out
 
                 /* Wait for handshake back */
                 chkct(c_mix_out, XS1_CT_END);
-                asm("outct res[%0],%1"::"r"(buffer_aud_ctl_chan),"r"(XS1_CT_END));
+                asm volatile("outct res[%0],%1"::"r"(buffer_aud_ctl_chan),"r"(XS1_CT_END));
 
                 SET_SHARED_GLOBAL(g_freqChange, 0);
                 ENABLE_INTERRUPTS();
@@ -1000,7 +1000,7 @@ void decouple(chanend c_mix_out
                 {
                     int p, len;
                     GET_SHARED_GLOBAL(p, g_aud_to_host_buffer);
-                    asm("ldw %0, %1[0]":"=r"(len):"r"(p));
+                    asm volatile("ldw %0, %1[0]":"=r"(len):"r"(p));
                     XUD_SetReady_InPtr(aud_to_host_usb_ep, p+4, len);
                 }
                 continue;