diff --git a/libsrc/cbm/cbm_read.s b/libsrc/cbm/cbm_read.s
index b010966a3..a30983302 100644
--- a/libsrc/cbm/cbm_read.s
+++ b/libsrc/cbm/cbm_read.s
@@ -45,11 +45,11 @@
 
 
 _cbm_read:
-        eor     #$FF
-        sta     ptr1
-        txa
-        eor     #$FF
-        sta     ptr1+1          ; Save -size-1
+        inx
+        stx     ptr1+1
+        tax
+        inx
+        stx     ptr1            ; Save size with each byte incremented.
 
         jsr     popax
         sta     ptr2
@@ -92,9 +92,9 @@ _cbm_read:
         bne     @L3
         inc     ptr3+1          ; ++bytesread;
 
-@L3:    inc     ptr1
+@L3:    dec     ptr1
         bne     @L1
-        inc     ptr1+1
+        dec     ptr1+1
         bne     @L1
 
 @L4:    jsr     CLRCH
diff --git a/libsrc/cbm/cbm_write.s b/libsrc/cbm/cbm_write.s
index 2d932d04a..a199c1d90 100644
--- a/libsrc/cbm/cbm_write.s
+++ b/libsrc/cbm/cbm_write.s
@@ -39,11 +39,11 @@
 _cbm_write:
         sta     ptr3
         stx     ptr3+1          ; Save size
-        eor     #$FF
-        sta     ptr1
-        txa
-        eor     #$FF
-        sta     ptr1+1          ; Save -size-1
+        inx
+        stx     ptr1+1
+        tax
+        inx
+        stx     ptr1            ; Save size with each byte incremented
 
         jsr     popax
         sta     ptr2
@@ -69,9 +69,9 @@ _cbm_write:
 
 @L2:    jsr     BSOUT           ; cbm_k_bsout (A);
 
-@L3:    inc     ptr1            ; --size;
+@L3:    dec     ptr1            ; --size;
         bne     @L1
-        inc     ptr1+1
+        dec     ptr1+1
         bne     @L1
 
         jsr     CLRCH
diff --git a/libsrc/common/getcwd.s b/libsrc/common/getcwd.s
index 22b6ceded..c0a1c3634 100644
--- a/libsrc/common/getcwd.s
+++ b/libsrc/common/getcwd.s
@@ -17,22 +17,22 @@
 
 .proc   _getcwd
 
-; Remember -size-1 because this simplifies the following loop
+; Remember size with each byte incremented because this simplifies the following loop
 
-        eor     #$FF
-        sta     ptr2
-        txa
-        eor     #$FF
-        sta     ptr2+1
+        inx
+        stx     ptr2+1
+        tax
+        inx
+        stx     ptr2
 
         jsr     popptr1         ; Get buf to ptr1
 
 ; Copy __cwd to the given buffer checking the length
 
         ; ldy     #$00          is guaranteed by popptr1
-loop:   inc     ptr2
+loop:   dec     ptr2
         bne     @L1
-        inc     ptr2+1
+        dec     ptr2+1
         beq     overflow
 
 ; Copy one character, end the loop if the zero terminator is reached. We