diff --git a/src/engine/platform/sound/supervision.c b/src/engine/platform/sound/supervision.c
index cba6df3ca..c042ba313 100644
--- a/src/engine/platform/sound/supervision.c
+++ b/src/engine/platform/sound/supervision.c
@@ -3,8 +3,6 @@
 
 #include "supervision.h"
 
-enum {FALSE, TRUE};
-
 #include <string.h>
 
 #define SV_SAMPLE_RATE ((svision->UNSCALED_CLOCK)/64)
@@ -71,7 +69,7 @@ void supervision_sound_stream_update(struct svision_t *svision, uint8 *stream, u
             chout[j] = 0;
             if (svision->ch[j].size != 0) {
                 if (svision->ch[j].on || channel->count != 0) {
-                    BOOL on = FALSE;
+                    BOOL on = 0;
                     switch (svision->ch[j].waveform) {
                         case 0: // 12.5%
                             on = svision->ch[j].pos < (28 * svision->ch[j].size) >> 5;
@@ -106,7 +104,7 @@ void supervision_sound_stream_update(struct svision_t *svision, uint8 *stream, u
                     // Transition from off to on
                     if (channel->on) {
                         memcpy(&svision->ch[j], channel, sizeof(svision->ch[j]));
-                        channel->on = FALSE;
+                        channel->on = 0;
                     }
                 }
             }
@@ -160,7 +158,7 @@ void supervision_sound_stream_update(struct svision_t *svision, uint8 *stream, u
             }
             svision->m_dma.pos += svision->m_dma.step;
             if (svision->m_dma.pos >= svision->m_dma.size) {
-                svision->m_dma.on = FALSE;
+                svision->m_dma.on = 0;
             }
         }
 
diff --git a/src/engine/platform/supervision.cpp b/src/engine/platform/supervision.cpp
index 7fbbe34ac..d1a851d9a 100644
--- a/src/engine/platform/supervision.cpp
+++ b/src/engine/platform/supervision.cpp
@@ -57,12 +57,12 @@ const char** DivPlatformSupervision::getRegisterSheet() {
 }
 
 void DivPlatformSupervision::acquire(short** buf, size_t len) {
-  for (size_t h=0; h<len; h++) {
-    int mask_bits=0;
-    for (int i=0; i<4; i++)
-      mask_bits |= isMuted[i]?0:8>>i;
-    supervision_set_mute_mask(&svision,mask_bits);
+  int mask_bits=0;
+  for (int i=0; i<4; i++)
+    mask_bits |= isMuted[i]?0:8>>i;
+  supervision_set_mute_mask(&svision,mask_bits);
 
+  for (size_t h=0; h<len; h++) {
     while (!writes.empty()) {
       QueuedWrite w=writes.front();
       supervision_memorymap_registers_write(&svision,w.addr|0x2000,w.val);