*
STRCAT
*
         PLA
         STA   RETADR
         PLA
         STA   RETADR+1
         PLA
         STA   :MLEN
         PLA
         STA   ADDR2
         PLA
         STA   ADDR2+1
         PLA
         STA   ADDR1
         PLA
         STA   ADDR1+1
         LDY   #0
         LDA   (ADDR1),Y
         STA   :S1LEN
         STA   :S1IND
         INC   :S1IND
         LDA   (ADDR2),Y
         STA   :S2LEN
         LDA   #1
         STA   :S2IND
         LDA   :S2LEN
         CLC
         ADC   :S1LEN
         STA   :S3LEN
         BCS   :TOOLONG
         CMP   :MLEN
         BEQ   :LENOK
         BCC   :LENOK
:TOOLONG
         LDA   #$0FF
         STA   :SOVF
         LDA   :MLEN
         SEC
         SBC   :S1LEN
         BCC   :EXIT
         STA   :SCNT
         LDA   :MLEN
         STA   :S1LEN
         JMP   :DOCAT
:LENOK
         STA   :S1LEN
         LDA   #0
         STA   :SOVF
         LDA   :S2LEN
         STA   :SCNT
:DOCAT
         LDA   :SCNT
         BEQ   :EXIT
:CATLP
         LDY   :S2IND
         LDA   (ADDR2),Y
         LDY   :S1IND
         STA   (ADDR1),Y
         INC   :S1IND
         INC   :S2IND
         DEC   :SCNT
         BNE   :CATLP
:EXIT
         LDA   :S1LEN
         LDY   #0
         STA   (ADDR1),Y
         LDA   :SOVF
         ROR   A
         LDA   RETADR+1
         PHA
         LDA   RETADR
         PHA
         LDY   #0
         LDA   (ADDR1),Y
         STA   RETLEN
         LDA   #1
:RLP
         LDA   (ADDR1),Y
         STA   RETURN,Y
         CPY   RETLEN
         INY
         BNE   :RLP
         LDA   RETLEN
         LDY   #0
         STA   (ADDR1),Y
         LDX   :S3LEN
         RTS
:S3LEN   DS    1
:S1LEN   DS    1
:S1IND   DS    1
:S2LEN   DS    1
:S2IND   DS    1
:MLEN    DS    1
:SCNT    DS    1
:SOVF    DS    1