Data commit

Task/CRC-32/NOWUT/crc-32.nowut

@@ -0,0 +1,63 @@
+; link with PIOxxx.OBJ
+
+        sectionbss
+
+crctable.d:     resd 256
+
+        sectiondata
+
+havetable.b:    db 0
+string:         db "The quick brown fox jumps over the lazy dog"
+stringend:
+                db 13,10,0        ; carriage return and null terminator
+
+        sectioncode
+
+start!
+        gosub initplatform
+
+        beginfunc
+        localvar crc.d
+
+        callex ,printnt,"input = ".a
+        callex ,printnt,string
+
+        callex ,printnt,"The CRC-32 checksum = ".a
+        callex crc,crc32,string,stringend
+        callex ,printhexr,crc
+
+        endfunc
+        end
+
+crc32:
+        beginfunc bufend.d,buf.d
+        localvar i.d,j.d,k.d,k2.d,crc.d
+
+        ifunequal havetable,0,tabledone
+        i=0
+        whileless i,256
+
+        k=i > j=8
+        countdown j
+        k2=k > k=_ shr 1
+        ifequal k2 and 1,0,noxor > k=_ xor $EDB88320
+noxor:
+        nextcount
+
+        crctable(i shl 2)=k
+        i=_+1
+        wend
+
+        havetable=1
+tabledone:
+
+        crc=-1
+
+        whileless buf,bufend
+        crc=_ shr 8 xor crctable(crc and $FF xor [buf].b shl 2)
+        buf=_+1
+        wend
+
+        crc=_ xor -1
+        endfunc crc
+        returnex 8                        ; clean off 2 parameters from the stack