diff --git a/libsrc/Makefile b/libsrc/Makefile
index 970ae6972..9bbb0aadb 100644
--- a/libsrc/Makefile
+++ b/libsrc/Makefile
@@ -197,9 +197,9 @@ ifeq ($(TARGET),$(filter $(TARGET),$(GEOS)))
 endif
 
 ifeq ($(TARGET),c65)
-# FIXME: the compiler does not work for 4510 yet
+# FIXME: this does not work because of the SP vs C_SP clash
 else ifeq ($(TARGET),mega65)
-# FIXME: the compiler does not work for 45GS02 yet
+# FIXME: this does not work because of the SP vs C_SP clash
 else
 SRCDIRS += common   \
            conio    \
diff --git a/src/cc65/main.c b/src/cc65/main.c
index abed6acae..648c603cd 100644
--- a/src/cc65/main.c
+++ b/src/cc65/main.c
@@ -348,7 +348,6 @@ static void DefineCpuMacros (void)
         case CPU_NONE:
         case CPU_SWEET16:
         case CPU_M740:
-        case CPU_4510:
         case CPU_UNKNOWN:
             CPUName = (CPU == CPU_UNKNOWN)? "unknown" : CPUNames[CPU];
             Internal ("Invalid CPU \"%s\"", CPUName);
@@ -382,6 +381,14 @@ static void DefineCpuMacros (void)
             DefineNumericMacro ("__CPU_HUC6280__", 1);
             break;
 
+        case CPU_4510:
+            DefineNumericMacro ("__CPU_4510__", 1);
+            break;
+
+        case CPU_45GS02:
+            DefineNumericMacro ("__CPU_45GS02__", 1);
+            break;
+
         default:
             FAIL ("Unexpected value in switch");
             break;
@@ -397,6 +404,8 @@ static void DefineCpuMacros (void)
     DefineNumericMacro ("__CPU_ISET_65C02__", CPU_ISET_65C02);
     DefineNumericMacro ("__CPU_ISET_65816__", CPU_ISET_65816);
     DefineNumericMacro ("__CPU_ISET_HUC6280__", CPU_ISET_HUC6280);
+    DefineNumericMacro ("__CPU_ISET_4510__", CPU_ISET_4510);
+    DefineNumericMacro ("__CPU_ISET_45GS02__", CPU_ISET_45GS02);
 
     /* Now define the macro that contains the bit set with the available
     ** cpu instructions.