M .gitignore → .gitignore

@@ -1,5 +1,6 @@ 
 xyw.exe
 xyw
+examples/test.xyw
 tmp/
 *.o
-*.xim+*.xim

A examples/lib/contains.xyw

@@ -0,0 +1,44 @@ 
+; <str> <fragment> contains -> $00|$01
+; xw -> index of string
+; yw -> index of fragment
+; y  -> internal index within fragment
+; a16 b16 -[xxwyw]- a8
+.label contains 
+   POPyw POPxw ; save both addresses to xw and yw
+   $00 POPy ; set y to zero
+   .label contains.checks
+     ; if at end of fragment, all good
+     LDByw $00 EQU contains.ok JCNw
+     ; if at end of string, fail
+     LDBxw $00 EQU contains.fail JCNw
+     ; check if contents of indexes are different
+     LDBxyw NEQ contains.different JCNw
+     ; otherwise they are matching 
+     ; increment internal fragment index
+     INCy
+     ; increment both indexes 
+     INCxyw
+     contains.checks JMPw
+   .label contains.str.incr
+     ; increment only string
+     INCxw
+     contains.checks JMPw
+   .label contains.different
+     ; letters are different
+     ; if started matching fragment, reset
+     PSHy contains.reset JCNw
+     ; otherwise increment string index
+     contains.str.incr JMPw
+   .label contains.reset
+     ; reset fragment scan 
+     PSHyw $00 PSHy SUBw POPyw
+     ; reset string scan
+     PSHxw $00 PSHy SUBw POPxw
+     $00 POPy
+     contains.str.incr JMPw
+   .label contains.fail
+     ; no match
+     $00 RTS
+   .label contains.ok
+     ; fragment is contained in string
+     $01 RTS