1 files changed, 8 insertions, 4 deletions
diff --git a/Kernel/BlkDev/DskFDC.HC b/Kernel/BlkDev/DskFDC.HC
index 9b14e4e..53cdccb 100644
--- a/Kernel/BlkDev/DskFDC.HC
+++ b/Kernel/BlkDev/DskFDC.HC
@@ -61,36 +61,40 @@ U8 FDCReadByte(CBlkDev *bd)
 {
   // Read byte from FDC.
 
-  U8 byte; // The byte read
+  U64 byte,msr; // The byte read, and the MSR contents
   F64 timeout; // Timeout variable
   timeout = tS()+3.0; // 3 second timeout
 
   while (TRUE) {
-    if (InU8(bd->base0+FDC_MSR_DSR)>>6==3) {
+    msr=InU8(bd->base0+FDC_MSR_DSR);
+    if (msr>>6==3) {
       byte=InU8(bd->base0+FDC_DATA);
       return byte;
     }
     if (tS()>timeout) {
       throw('BlkDev');
     }
+    Yield;
   }
 }
 
 U0 FDCSendByte(CBlkDev *bd,U8 byte)
 {
   // Send byte to FDC.
-
+  U64 msr; // MSR contents
   F64 timeout; // Timeout variable
   timeout=tS()+3.0; // 3 second timeout
 
   while (TRUE) {
-    if (InU8(bd->base0+FDC_MSR_DSR)>>6==2) {
+    msr=InU8(bd->base0+FDC_MSR_DSR);
+    if (msr>>6==2) {
       OutU8(bd->base0+FDC_DATA,byte);
       return;
     }
     if (tS()>timeout) {
       throw('BlkDev');
     }
+    Yield;
   }
 }