diff --git a/libsrc/cbm/c_basin.s b/libsrc/cbm/c_basin.s
index 80dda8bdb..5dc0c0f66 100644
--- a/libsrc/cbm/c_basin.s
+++ b/libsrc/cbm/c_basin.s
@@ -4,7 +4,11 @@
 ; unsigned char __fastcall__ cbm_k_basin (void);
 ;
 
-       	.export	       	_cbm_k_basin
-        .import         BASIN
+	.export		_cbm_k_basin
+	.import		BASIN
 
-_cbm_k_basin = BASIN
+
+_cbm_k_basin:
+	jsr	BASIN
+	ldx	#0		; Clear high byte
+	rts
diff --git a/libsrc/cbm/c_open.s b/libsrc/cbm/c_open.s
index 300aa54ad..b8f952781 100644
--- a/libsrc/cbm/c_open.s
+++ b/libsrc/cbm/c_open.s
@@ -10,7 +10,7 @@
 
 _cbm_k_open:
 	jsr	OPEN
+	ldx     #0              ; Clear high byte
 	bcs	@NotOk
-        lda     #0
-@NotOk:	ldx     #0              ; Clear high byte
-        rts
+        txa
+@NotOk: rts
diff --git a/libsrc/cbm/c_readst.s b/libsrc/cbm/c_readst.s
index 2a3075acc..4aeab41b3 100644
--- a/libsrc/cbm/c_readst.s
+++ b/libsrc/cbm/c_readst.s
@@ -4,8 +4,11 @@
 ; unsigned char __fastcall__ cbm_k_readst (void);
 ;
 
-       	.export	       	_cbm_k_readst
-        .import         READST
+	.export		_cbm_k_readst
+	.import		READST
 
 
-_cbm_k_readst = READST
+_cbm_k_readst:
+	jsr	READST
+	ldx	#0		; Clear high byte
+	rts