diff --git a/dlls/ntdll/exception.c b/dlls/ntdll/exception.c
index 643661b5525..8bfe7b7046e 100644
--- a/dlls/ntdll/exception.c
+++ b/dlls/ntdll/exception.c
@@ -49,7 +49,7 @@ typedef struct
 #elif defined(__sparc__)
 # define GET_IP(context) ((LPVOID)(context)->pc)
 #elif defined(__powerpc__)
-# define GET_IP(context) ((LPVOID)(context)->Fill[0])
+# define GET_IP(context) ((LPVOID)(context)->Iar)
 #else
 # error You must define GET_IP for this CPU
 #endif
diff --git a/dlls/ntdll/signal_powerpc.c b/dlls/ntdll/signal_powerpc.c
index 4db311032d0..594af949c6f 100644
--- a/dlls/ntdll/signal_powerpc.c
+++ b/dlls/ntdll/signal_powerpc.c
@@ -76,7 +76,7 @@ typedef struct ucontext SIGCONTEXT;
 
 WINE_DEFAULT_DEBUG_CHANNEL(seh);
 
-typedef int (*wine_signal_handler)(unsigned sig);
+typedef int (*wine_signal_handler)(unsigned int sig);
 
 static wine_signal_handler handlers[256];
 
@@ -86,7 +86,7 @@ static sigset_t all_sigs;
 /***********************************************************************
  *           dispatch_signal
  */
-inline static int dispatch_signal(unsigned sig)
+inline static int dispatch_signal(unsigned int sig)
 {
     if (handlers[sig] == NULL) return 0;
     return handlers[sig](sig);
@@ -106,7 +106,7 @@ static void save_context( CONTEXT *context, const SIGCONTEXT *sigcontext )
 	C(21); C(22); C(23); C(24); C(25); C(26); C(27); C(28); C(29); C(30);
 	C(31);
 
-	CX(Fill[0],nip);
+	CX(Iar,nip);
 	CX(Msr,msr);
 	CX(Ctr,ctr);
 #undef CX
@@ -139,7 +139,7 @@ static void restore_context( const CONTEXT *context, SIGCONTEXT *sigcontext )
 	C(21); C(22); C(23); C(24); C(25); C(26); C(27); C(28); C(29); C(30);
 	C(31);
 
-	CX(Fill[0],nip);
+	CX(Iar,nip);
 	CX(Msr,msr);
 	CX(Ctr,ctr);
 #undef CX
@@ -222,7 +222,7 @@ static HANDLER_DEF(segv_handler)
     rec.NumberParameters = 0;
     switch (__siginfo->si_signo) {
     case SIGSEGV:
-    	switch (__siginfo->si_code) {
+    	switch ( __siginfo->si_code & 0xffff ) {
 	case SEGV_MAPERR:
 	case SEGV_ACCERR:
 		rec.NumberParameters = 2;
@@ -237,7 +237,7 @@ static HANDLER_DEF(segv_handler)
 	}
     	break;
     case SIGBUS:
-    	switch (__siginfo->si_code) {
+    	switch ( __siginfo->si_code & 0xffff ) {
 	case BUS_ADRALN:
 		rec.ExceptionCode = EXCEPTION_DATATYPE_MISALIGNMENT;
 		break;
@@ -256,7 +256,7 @@ static HANDLER_DEF(segv_handler)
 	}
     	break;
     case SIGILL:
-    	switch (__siginfo->si_code) {
+    	switch ( __siginfo->si_code & 0xffff ) {
 	case ILL_ILLOPC: /* illegal opcode */
 	case ILL_ILLOPN: /* illegal operand */
 	case ILL_ILLADR: /* illegal addressing mode */
@@ -298,7 +298,7 @@ static HANDLER_DEF(trap_handler)
     rec.NumberParameters = 0;
 
     /* FIXME: check if we might need to modify PC */
-    switch (__siginfo->si_code) {
+    switch (__siginfo->si_code & 0xffff) {
     case TRAP_BRKPT:
         rec.ExceptionCode = EXCEPTION_BREAKPOINT;
     	break;
@@ -324,7 +324,7 @@ static HANDLER_DEF(fpe_handler)
     /*save_fpu( &context, HANDLER_CONTEXT );*/
     save_context( &context, HANDLER_CONTEXT );
 
-    switch ( __siginfo->si_code ) {
+    switch ( __siginfo->si_code  & 0xffff ) {
     case FPE_FLTSUB:
         rec.ExceptionCode = EXCEPTION_ARRAY_BOUNDS_EXCEEDED;
         break;
@@ -377,7 +377,7 @@ static HANDLER_DEF(int_handler)
         rec.ExceptionCode    = CONTROL_C_EXIT;
         rec.ExceptionFlags   = EXCEPTION_CONTINUABLE;
         rec.ExceptionRecord  = NULL;
-        rec.ExceptionAddress = (LPVOID)context.Fill[0];
+        rec.ExceptionAddress = (LPVOID)context.Iar;
         rec.NumberParameters = 0;
         EXC_RtlRaiseException( &rec, &context );
         restore_context( &context, HANDLER_CONTEXT );
@@ -411,7 +411,7 @@ static int set_handler( int sig, int have_sigaltstack, void (*func)() )
 /***********************************************************************
  *           __wine_set_signal_handler   (NTDLL.@)
  */
-int __wine_set_signal_handler(unsigned sig, wine_signal_handler wsh)
+int __wine_set_signal_handler(unsigned int sig, wine_signal_handler wsh)
 {
     if (sig > sizeof(handlers) / sizeof(handlers[0])) return -1;
     if (handlers[sig] != NULL) return -2;
diff --git a/include/winnt.h b/include/winnt.h
index 2b3e1e0da41..858e661a845 100644
--- a/include/winnt.h
+++ b/include/winnt.h
@@ -959,7 +959,7 @@ typedef struct
 
     /* These are selected by CONTEXT_CONTROL */
     DWORD Msr;
-    DWORD Iar;
+    DWORD Iar; /* Instruction Address Register , aka PC ... */
     DWORD Lr;
     DWORD Ctr;
 
diff --git a/server/context_powerpc.c b/server/context_powerpc.c
index da5fe7e67ff..3dca87429f4 100644
--- a/server/context_powerpc.c
+++ b/server/context_powerpc.c
@@ -56,18 +56,13 @@ static void get_thread_context( struct thread *thread, unsigned int flags, CONTE
 #undef IREG
 	    XREG(37,Xer);
 	    XREG(38,Cr);
-
         }
         if (flags & CONTEXT_CONTROL)
         {
+	    XREG(32,Iar);
 	    XREG(33,Msr);
 	    XREG(35,Ctr);
-
-	    XREG(32,Fill[0]); /* misused for PC / nip */
-
-	/* what is Iar? Lr? */
-	    /*XREG(33*4,Iar);*/
-	    /*XREG(33*4,Lr);*/
+	    XREG(36,Lr); /* 36 is LNK ... probably Lr ? */
         }
     }
     if (flags & CONTEXT_FLOATING_POINT)
@@ -137,14 +132,10 @@ static void set_thread_context( struct thread *thread, unsigned int flags, const
         }
         if (flags & CONTEXT_CONTROL)
         {
+	    XREG(32,Iar);
 	    XREG(33,Msr);
 	    XREG(35,Ctr);
-
-	    XREG(32,Fill[0]); /* misused for PC / nip */
-
-	/* what is Iar? Lr? */
-	    /*XREG(33*4,Iar);*/
-	    /*XREG(33*4,Lr);*/
+	    XREG(36,Lr);
         }
     }
     if (flags & CONTEXT_FLOATING_POINT)
@@ -202,7 +193,7 @@ static void copy_context( CONTEXT *to, const CONTEXT *from, int flags )
     {
     	CREG(Msr);
     	CREG(Ctr);
-    	CREG(Fill[0]);
+    	CREG(Iar);
     }
     if (flags & CONTEXT_INTEGER)
     {
@@ -256,13 +247,13 @@ static void copy_context( CONTEXT *to, const CONTEXT *from, int flags )
 void *get_thread_ip( struct thread *thread )
 {
     CONTEXT context;
-    context.Fill[0] = 0;
+    context.Iar = 0;
     if (suspend_for_ptrace( thread ))
     {
         get_thread_context( thread, CONTEXT_CONTROL, &context );
         resume_thread( thread );
     }
-    return (void *)context.Fill[0];
+    return (void *)context.Iar;
 }
 
 /* determine if we should continue the thread in single-step mode */