ASMB,A,B,L

* BINARY LOADER
* From 13-3 CE Handbook

RDR   EQU 13B     READER SELECT CODE

* 4KW=07700
* 8KW=17700
*12KW=27700
*16KW=37700
*24KW=57700
*32KW=77700

      ORG 77700B  DEPENDS ON CORE SIZE
LOAD  CLC 0,C     TURN OFF ALL DEVICES
      LDA STAI
      LIB 1       CHECK FOR OPTIONS
      SLB         S-REG(0)=1?
      CLA         YES: CHECKSUM OPTION
      SSB         S-REG(15)=1?
      LDA CPAI    YES: VERIFY CORE OPT.
      STA OPTI    STORE OPTIONAL INST.
      CLB,RSS     BYPASS EOT CHECK
CONT  LDB CM11    B=-11 FOR EOT CHECK
EOTCH INB,SZB     END OF TAPE?
      JMP LD1     NO GET NEXT CHAR
      CLC 0,C     TURN OFF ALL DEVICES
      HLT 77B     END OF TAPE
      JMP LOAD    START NEXT TAPE
LD1   JSB CHAR    GET A CHARACTER
      SZA,RSS     IS IT THE WORD COUNT?
      JMP EOTCH   NO: CHECK FOR EOT
      CMA,CLE,INA (2'S COMP WORD COUNT)
      STA COUNT   SAVE WORD COUNT
      JSB CHAR    SKIP NEXT CHAR
      JSB WORD    GET STARTING ADDRESS
      STA 1       INITIALIZE CHECKSUM IN B
      STA ADDRS   ALSO IN ADDRESS
LD2   LDA ADDRS   CHECK FOR ADDR>=LOADER
      ADA MAXAD
      SEZ         E-REG=0  OK
      JMP ADERR   BAD ADDRESS
      JSB WORD    NEXT WORD IN A-REG
      ADB 0       CONTINUE CHECKSUM
OPTI  NOP         STA, CPA, OR NOP
      CLE,RSS     NORMALLY BYPASS HALT
      HLT 0B      DID NOT COMPARE
      ISZ ADDRS   INCREMENT ADDRESS
      ISZ COUNT   UPDATE WORD COUNT
      JMP LD2     NEXT WORD
      JSB WORD    END OF RECORD
      CPB 0       COMPARE CHECKSUMS
      JMP CONT    LOOK FOR END OF TAPE
      HLT 11B     CHECKSUM ERROR
      JMP LOAD    START OVER
ADERR HLT 55B     ILLEGAL ADDRESS
      JMP LOAD    START OVER
WORD  NOP         READ ONE BYTE
      JSB CHAR    FIRST BYTE
      ALF,ALF     POSITION BYTE
      STA TEMP    SAVE IT
      JSB CHAR    SECOND BYTE
      IOR TEMP    MERGE BYTES
      JMP WORD,I  RETURN WITH WORD
CHAR  NOP         READ BYTE FROM READER
      STC RDR,C   INITIATE READ
RLOOP SFS RDR     ** CHECK THESE IF  **
      JMP RLOOP   ** LOADER BOMBED   **
      LIA RDR     GET BYTE
      JMP CHAR,I  HAVE BYTE A-REG(0-7)
STAI  STA ADDRS,I HAVE OPTI FOR NORMAL LOAD
CPAI  CPA ADDRS,I OPTI FOR VERIFY OPTION
MAXAD ABS -LDR    LOADER ADDRESS (2'S COMP)
CM11  DEC -11     EOT ERROR COUNT
COUNT BSS 1       WORD COUNT
ADDRS BSS 1       ADDRESS LOCATION
TEMP  BSS 1       HOLDS FIRST BYTE
LDR   EQU 17700B  LOADER ADDRESS
*CHECK 17764,17765 IF LOADER IS BOMBED
*17763,17764,17766 DEPEND ON READER SELECT CODE
*17772 DEPENDS ON CORE SIZE