Added further optimizations and unit tests.

libsrc/common/strcspn.s

@@ -1,54 +1,54 @@
 ;
 ; Ullrich von Bassewitz, 11.06.1998
+; Christian Krueger: 05-Aug-2013, optimization
 ;
 ; size_t strcspn (const char* s1, const char* s2);
 ;
 
         .export         _strcspn
-        .import         popax
-        .importzp       ptr1, ptr2, tmp1, tmp2, tmp3
+        .import         popax, _strlen
+        .importzp       ptr1, ptr2, tmp1, tmp2
 
 _strcspn:
-        sta     ptr2            ; Save s2
-        stx     ptr2+1
-        jsr     popax           ; Get s1
-        sta     ptr1
-        stx     ptr1+1
-        ldx     #0              ; low counter byte
-        stx     tmp1            ; high counter byte
-        ldy     #$00
+        jsr _strlen         ; get length in a/x and transfer s2 to ptr1
+                            ; Note: It does not make sense to
+                            ; have more than 255 test chars, so
+                            ; we don't support a high byte here! (ptr1+1 is
+                            ; also unchanged in strlen then (important!))
+                            ; -> the original implementation also
+                            ; ignored this case
 
-L1:     lda     (ptr1),y        ; get next char from s1
-        beq     L6              ; jump if done
-        sta     tmp2            ; save char
+        sta tmp1            ; tmp1 = strlen of test chars
+        jsr popax           ; get and save s1
+        sta ptr2            ; to ptr2
+        stx ptr2+1
+        ldx #0              ; low counter byte
+        stx tmp2            ; high counter byte
+
+loadChar:
+        ldy #0
+        lda (ptr2),y        ; get next char from s1
+        beq leave           ; handly byte of s1
+advance:
+        inc ptr2            ; advance string position to test
+        bne check
+        inc ptr2+1
+        dey                 ; correct next iny (faster/shorter than bne...)
+
+checkNext:
         iny
-        bne     L2
-        inc     ptr1+1
-L2:     sty     tmp3            ; save index into s1
+check:  cpy tmp1            ; compare with length of test character string
+        beq endOfTestChars
+        cmp (ptr1),y        ; found matching char?
+        bne checkNext           
 
-        ldy     #0              ; get index into s2
-L3:     lda     (ptr2),y        ;
-        beq     L4              ; jump if done
-        cmp     tmp2
-        beq     L6
-        iny
-        bne     L3
-
-; The character was not found in s2. Increment the counter and start over
-
-L4:     ldy     tmp3            ; reload index
-        inx
-        bne     L1
-        inc     tmp1
-        bne     L1
-
-; The character was found, or we reached the end of s1. Return count of
-; characters
-
-L6:     txa                     ; get low counter byte
-        ldx     tmp1            ; get high counter byte
+leave:  txa                 ; restore position of finding
+        ldx tmp2            ; and return
         rts
 
-
-
+endOfTestChars:
+        inx
+        bne loadChar
+        inc tmp2
+        bne loadChar        ; like bra...