diff --git a/src/libsrc/sane.pla b/src/libsrc/sane.pla
index d302af1..0811e89 100644
--- a/src/libsrc/sane.pla
+++ b/src/libsrc/sane.pla
@@ -22,10 +22,6 @@ export word[7] sane = @fpInit, @fpDefaultHalt, @uninit0, @uninit1, @uninit2, @un
 //
 word fp6502
 //
-// Pointer to Halt handler
-//
-word hhaddr
-//
 // PLASMA <-> SANE interface routines
 //
 asm equates
@@ -56,6 +52,7 @@ asm xfpHalt
         LDX     #$F7
 end
 asm fpHalt
+        STA     $C008
         TXA
         LDX     ESP
         STA     ESTKL,X
@@ -424,7 +421,9 @@ end
 // Default HALT handler
 //
 def fpDefaultHalt(pstatus)
+    sane[8]() // zpRestore
     puts("SANE Exception="); puti(pstatus->8); puts("!\n")
+    sane[7]() // zpSave
     return pstatus=>4
 end
 //
@@ -626,9 +625,7 @@ def fpInit()
             //
             // Install AUX HALT handler
             //
-            hhaddr = @xfpHalt
-            (@fixupHLT)=>1 = @sane+2
-            xfpOp1($0005, @hhaddr)
+            xfpOp1($0005, @xfpHalt)
         else
             //
             // Fixup MAIN calls in interface routines
@@ -647,14 +644,17 @@ def fpInit()
             //
             // Install MAIN HALT handler
             //
-            hhaddr = @fpHalt
-            (@fixupHLT)=>1 = @sane+2
-            fpOp1($0005, @hhaddr)
+            fpOp1($0005, @fpHalt)
         fin
         sane[5] = @elemsLoad1
         sane[6] = @elemsLoad2
     fin
-    sane[1] = @fpDefaultHalt
+    (@fixupHLT)=>1 = @sane+2
+    sane[1]        = @fpDefaultHalt
+    //
+    // Reset environment word
+    //
+    sane[3]($0001, $0000)
 end
 //
 // Uninitialized placeholders of API
diff --git a/src/samplesrc/sanity.pla b/src/samplesrc/sanity.pla
index 67742c0..2048e0f 100644
--- a/src/samplesrc/sanity.pla
+++ b/src/samplesrc/sanity.pla
@@ -10,6 +10,7 @@ word iA, iB, iC, zero, fpEnv
 byte xT[t_extended]
 
 def myException(pstatus)
+    sane:zpRestore()
     puts("Floating point exception:")
     if pstatus->8 & FBINVALID; puts(" INVALID"); fin
     if pstatus->8 & FBUFLOW;   puts(" UNDERFLOW"); fin
@@ -17,6 +18,7 @@ def myException(pstatus)
     if pstatus->8 & FBDIVZER;  puts(" DIV_BY_ZERO"); fin
     if pstatus->8 & FBINEXACT; puts(" INEXACT"); fin
     putln
+    sane:zpSave()
     return pstatus=>4
 end
 
@@ -51,8 +53,14 @@ sane:fpOp2(FFINT|FOX2Z, @iC, @xT) // Convert ext T to int C
 sane:zpRestore()
 puti(iA); putc('/'); puti(iB); putc('='); puti(iC); putc('\n')
 sane:zpSave()
+//
+// Hook custom HALT exception handler and divide by zero :-)
+//
 sane:fpHalt = @myException
 fpEnv = sane:fpOp0(FOGETENV)
+//
+// Enable all exceptions
+//
 sane:fpOp1(FOSETENV, fpEnv | FBINVALID | FBUFLOW | FBOFLOW | FBDIVZER | FBINEXACT)
 sane:fpOp2(FFINT|FOZ2X, @xT, @iA) // Convert int A to ext T
 sane:fpOp2(FFINT|FODIV, @xT, @zero) // Div ZERO into ext T