diff --git a/devices/video/atimach64gx.cpp b/devices/video/atimach64gx.cpp
index dc3be86..1e701e2 100644
--- a/devices/video/atimach64gx.cpp
+++ b/devices/video/atimach64gx.cpp
@@ -362,6 +362,15 @@ uint32_t AtiMach64Gx::read_reg(uint32_t reg_offset, uint32_t size)
     return static_cast<uint32_t>(result);
 }
 
+#define WRITE_VALUE_AND_LOG() \
+    do { \
+        this->regs[reg_num] = new_value; \
+        LOG_F(9, "%s: write %s %04x.%c = %0*x = %08x", this->name.c_str(), \
+            get_reg_name(reg_num), reg_offset, SIZE_ARG(size), size * 2, \
+            (uint32_t)extract_bits<uint64_t>(value, offset * 8, size * 8), new_value \
+        ); \
+    } while (0)
+
 void AtiMach64Gx::write_reg(uint32_t reg_offset, uint32_t value, uint32_t size)
 {
     uint32_t reg_num = reg_offset >> 2;
@@ -389,6 +398,7 @@ void AtiMach64Gx::write_reg(uint32_t reg_offset, uint32_t value, uint32_t size)
         break;
     case ATI_CRTC_OFF_PITCH:
         new_value = value;
+        WRITE_VALUE_AND_LOG();
         this->crtc_update();
         return;
     case ATI_CRTC_INT_CNTL:
@@ -506,6 +516,7 @@ void AtiMach64Gx::write_reg(uint32_t reg_offset, uint32_t value, uint32_t size)
     case ATI_OVR_WID_LEFT_RIGHT:
     case ATI_OVR_WID_TOP_BOTTOM:
         new_value = value;
+        WRITE_VALUE_AND_LOG();
         if (value != 0) {
             LOG_F(ERROR, "%s: Unhandled value 0x%08x.", this->name.c_str(), value);
         }
@@ -515,12 +526,14 @@ void AtiMach64Gx::write_reg(uint32_t reg_offset, uint32_t value, uint32_t size)
         new_value = value;
         this->cursor_dirty = true;
         draw_fb = true;
+        WRITE_VALUE_AND_LOG();
         return;
     case ATI_CUR_OFFSET:
         new_value = value;
         if (old_value != new_value)
             this->cursor_dirty = true;
         draw_fb = true;
+        WRITE_VALUE_AND_LOG();
         return;
     case ATI_CUR_HORZ_VERT_OFF:
         new_value = value;
@@ -530,10 +543,12 @@ void AtiMach64Gx::write_reg(uint32_t reg_offset, uint32_t value, uint32_t size)
         )
             this->cursor_dirty = true;
         draw_fb = true;
+        WRITE_VALUE_AND_LOG();
         return;
     case ATI_CUR_HORZ_VERT_POSN:
         new_value = value;
         draw_fb = true;
+        WRITE_VALUE_AND_LOG();
         return;
     case ATI_DAC_REGS:
         new_value = old_value; // no change