diff --git a/gcc/ada/libgnat/system-vxworks-ppc-kernel.ads b/gcc/ada/libgnat/system-vxworks-ppc-kernel.ads
index b8a0ba17735..640150a17ea 100644
--- a/gcc/ada/libgnat/system-vxworks-ppc-kernel.ads
+++ b/gcc/ada/libgnat/system-vxworks-ppc-kernel.ads
@@ -69,8 +69,8 @@ package System is
    Null_Address : constant Address;
 
    Storage_Unit : constant := 8;
-   Word_Size    : constant := 32;
-   Memory_Size  : constant := 2 ** 32;
+   Word_Size    : constant := Standard'Word_Size;
+   Memory_Size  : constant := 2 ** Word_Size;
 
    --  Address comparison
 
diff --git a/gcc/ada/libgnat/system-vxworks-ppc-rtp-smp.ads b/gcc/ada/libgnat/system-vxworks-ppc-rtp-smp.ads
index ecfd7e695e7..0855721c9d3 100644
--- a/gcc/ada/libgnat/system-vxworks-ppc-rtp-smp.ads
+++ b/gcc/ada/libgnat/system-vxworks-ppc-rtp-smp.ads
@@ -71,8 +71,8 @@ package System is
    Null_Address : constant Address;
 
    Storage_Unit : constant := 8;
-   Word_Size    : constant := 32;
-   Memory_Size  : constant := 2 ** 32;
+   Word_Size    : constant := Standard'Word_Size;
+   Memory_Size  : constant := 2 ** Word_Size;
 
    --  Address comparison
 
diff --git a/gcc/ada/libgnat/system-vxworks-ppc-rtp.ads b/gcc/ada/libgnat/system-vxworks-ppc-rtp.ads
index 72fb96363ef..f72177f2e0f 100644
--- a/gcc/ada/libgnat/system-vxworks-ppc-rtp.ads
+++ b/gcc/ada/libgnat/system-vxworks-ppc-rtp.ads
@@ -71,8 +71,8 @@ package System is
    Null_Address : constant Address;
 
    Storage_Unit : constant := 8;
-   Word_Size    : constant := 32;
-   Memory_Size  : constant := 2 ** 32;
+   Word_Size    : constant := Standard'Word_Size;
+   Memory_Size  : constant := 2 ** Word_Size;
 
    --  Address comparison