A2osX/SCMASM.31/SCMASM.S.ASMGEN.txt

NEW
  AUTO 3,1
*--------------------------------------
*    ASSEMBLER MAIN DRIVER
*--------------------------------
ASM
*      LDX #0       X=0 FROM COMMAND DISPATCHER
       STX PASS     SET TO PASS 1
       STX ERROR.COUNT
       STX ERROR.COUNT+1
*      STX MACRO.LEVEL    ALREADY DONE IN GNL
*      STX PARAM.PNTR     ALREADY DONE IN GNL
*      STX PAGE.LENGTH    ALREADY DONE IN GNL
       STX PAGE.NUMBER
       STX PAGE.NUMBER+1
       JSR STINIT   INITIALIZE SYMBOL TABLE
       JSR RESTORE  IF IN INCLUDE, RESTORE
*--------------------------------
*      PERFORM NEXT PASS OF ASSEMBLY
*--------------------------------
ASM1   LDA ERROR.COUNT
       ORA ERROR.COUNT+1
       BEQ .1
       JMP ASM.END  PRINT # ERRORS AND ABORT ASSEMBLY
.1     LDX #1       INIT 2-BYTE VARIABLES
.2     LDA PP,X     POINT TO BEGINNING OF SOURCE PROGRAM
       STA SRCP,X
       STA MACSTK,X
       LDA #0
       STA CALL.CNTR,X   TOTAL # MACRO CALLS
       STA CALL.NUM,X    CURRENT MACRO CALL #
       STA ORGN+2,X      HIGH 16 OF ORIGIN
       DEX
       BPL .2
*---Following = $FF--------------
       STX DO.STACK      SET OUTER LEVEL TRUE (=$FF)
       STX LF.CONDITIONAL   do not list false sets (=$FF)
*---Following = $00--------------
       STA DUMMY.FLAG    NOT IN DUMMY SECTION
       STA PHASE.FLAG    NOT IN PHASE
       STA DO.INDEX      SET DO.STACK TO EMPTY
       STA LF.ALL        turn on main listing
       STA LF.MACRO      list macro expansions too
       STA LF.XTRA.BYTES list all bytes, use extra lines
       STA TF.FLAG       not in ".TF"
       STA DO.SKIP.CNT   not in ".DO"
       STA FLAG.MA       not in ".MA"
       STA NYBBLE.FLAG   .AC odd/even
       STA ORGN          ORIGIN = $0800
       STA TRGT          TARGET = $0800
*---Following = $08--------------
       LDA #$08
       STA ORGN+1
       STA TRGT+1
       JSR ASM.INIT       Initialize for particular assembler
*--------------------------------
*    MOVE NEXT LINE INTO WORKING BUFFER
*--------------------------------
ASM2   LDA $C000    CHECK FOR ABORT WITHOUT
       CMP #CHR.RETURN   CLEARING STROBE
       BNE .1
       JMP JMP.SOFT     YES, STOP RIGHT NOW
.1     LDX #$FF       INITIALIZE STACK POINTER
       TXS
       INX            MAKE X=0
       STX EMIT.COLUMN
       STX EXP.UNDEF     CLEAR UNDEFINED FLAG
       JSR SETUP.NEXT.LINE
       BCC .2       GOT A LINE
       JMP ENDM     NO MORE LINES, ACT LIKE .EN FOUND
*---CHECK CURRENT CONDITION------
.2     LDA DO.STACK      CURRENT LEVEL IN SIGN BIT
       BMI ASSEMBLE.ONE.LINE  TRUE, SO ASSEMBLE
*--------------------------------
*      SKIP TO .FIN OR .ELSE
*--------------------------------
SKIP.TO.FIN
       JSR SCAN.TO.OPCODE
       BCS .3
       LDX #DIR.QT.DO
       JSR DIR.SCAN.OR.FAIL
       BCC .1       NOT .DO
       INC DO.SKIP.CNT  .DO
       BNE .3       ...ALWAYS
.1     LDY DO.SKIP.CNT
       BNE .2       INSIDE A NESTED .DO, IGNORE .ELSE'S
       JSR DIR.SCAN.OR.FAIL
       BCS ASSEMBLE.ONE.LINE  FOUND .ELSE
.2     LDX #DIR.QT.FI
       JSR DIR.SCAN.OR.FAIL
       BCC .3       NOT .FIN
       LDY DO.SKIP.CNT  .FIN, SEE IF NESTED ONE
       BEQ ASSEMBLE.ONE.LINE  NO, ASSEMBLE THIS .FIN
       DEC DO.SKIP.CNT        YES, POP OFF THIS NEST
.3     BIT LF.CONDITIONAL     LIST CONDITIONAL LINES?
       BMI ASM2               NO, SKIP IT
       JSR CRLF.IF.LISTING    YES, NEW LINE
       JMP CMNT               AND LIST IT
*--------------------------------
*    ANALYZE SOURCE LINE
*--------------------------------
ASSEMBLE.ONE.LINE
       JSR CRLF.IF.LISTING
       JSR PACK.MACRO.LINE
       BCS CMNT     ...only list if MACRO definition line
       JSR GNC.UC.START    not MACRO line, get first char
       BCS CMNT          ...empty line
       BEQ .3            ...blank, so no label
       JSR CHECK.COMMENT.CHAR
       BEQ CMNT          ...comment (* or ;)
       JSR LABL      PROCESS LABEL DEFINITION
.3     JSR GNNB      Scan to opcode field
       BCS CMNT      ...none, only label on this line
       JSR CHECK.COMMENT.CHAR    might be a comment with no opcode
       BEQ CMNT     ...yes, there is a comment
       CMP #'>      CHECK IF MACRO OPCODE
       BEQ .4       ...YES
       CMP #'_      CHECK IF MACRO OPCODE
       BEQ .4       ...YES
       CMP #'='
       BEQ .5       '=' is synonym for .EQ
       STA SEARCH.KEY  FIRST OPCODE CHAR
       JSR GNC.UC
       STA SEARCH.KEY+1  2ND OPCODE CHAR
       JSR GNC.UC
       STA SEARCH.KEY+2  3RD OPCODE CHAR
       LDA SEARCH.KEY
       CMP #'.        IS IT A DIRECTIVE?
       BNE .6       NO, TRY NORMAL OPCODES
       LDA #OPTBL.DIR
       LDY /OPTBL.DIR
       CLC          INITIAL SEARCH
       JSR SEARCH.COMPRESSED.TABLE
       BCC OPER     ...NOT FOUND IN TABLE
       JSR PERFORM.DIRECTIVE
       JMP CMNT
.4     JMP MACRO.CALL
.5     JSR PSEQ     "=" is synonym for .EQ
       JMP CMNT
.6     JSR ASM.PARTICULAR
*--------------------------------
CMNT   LDA EXP.UNDEF
       BPL .1       NO UNDEFINED EXPRESSIONS ON THIS LINE
       LDA PASS
       BEQ .1       IF WE GOT THIS FAR, OKAY IN PASS 1
       JMP UNDF
.1     JSR LIST.SOURCE.IF.LISTING
       JMP ASM2      NEXT LINE
*--------------------------------
*--------------------------------
PERFORM.DIRECTIVE
       INY          POINT AT HIGH BYTE OF ADDRESS
       LDA (OPTBL.PNTR),Y
       PHA
       DEY
       LDA (OPTBL.PNTR),Y
       PHA
       RTS
*--------------------------------
OPER   LDY #QER2    ERROR--BAD OPCODE
       JMP SOFT.ERROR
*--------------------------------
*      EMIT ONE BYTE OF OBJECT CODE
*
*      IF IN PASS TWO THEN
*        ! IF LISTING THEN <LIST>
*        ! IF IN ".TF" THEN
*        !   ! <WRITE BYTE ON DISK>
*        ! ELSE IF NOT IN DUMMY SECTION THEN
*        !   !    ! IF IN PROTECTED AREA THEN
*        !   !    !   ! <ABORT ASSEMBLY>
*        !   !    ! ELSE <STORE BYTE IN TARGET>
*      INCREMENT ORIGIN AND ORIGIN.SAVE
*      IF NOT IN DUMMY SECTION THEN INCREMENT TARGET
*--------------------------------
EMIT.ZERO
       LDA #0
EMIT   LDY PASS      CHECK WHICH PASS
       BEQ .5        PASS 1, JUST INCREMENT LOCATION
       STA OBJ.BYTE  SAVE OBJECT BYTE
*---LIST THE BYTE----------------
       JSR P.EMITTED.BYTE
*---STORE THE BYTE---------------
       BIT DUMMY.FLAG    No output inside dummy section
       BMI .6            ...only increment the origin
       LDA OBJ.BYTE      GET OUTPUT BYTE
       BIT TF.FLAG  SEE IF IN ".TF"
       BMI .4       YES
       JSR USER.OBJECT.BYTE
       JMP .5       ...ALWAYS
.4     JSR DOUT     WRITE ON TARGET FILE
*---INCREMENT LOCATION-----------
.5     LDA DUMMY.FLAG  IF IN DUMMY SECTION,
       BMI .6            THEN ONLY INCREMENT ORGN
       >INCD TRGT        BUMP TARGET ADDRESS
       >INCD ORIGIN.SAVE      AND ORIGIN OUTSIDE .PH
.6     >INCD ORGN        BUMP CURRENT ORIGIN
       RTS
*--------------------------------
STORE.OBJECT.BYTE
       LDA TRGT+1   TARGET PAGE
       BNE .1       NOT PAGE ZERO
       LDA TRGT     ALLOW $00-$1E
       CMP #$1F
       BCC .4       SAFE
       BCS .3       NOT SAFE
*---ALLOW $300-$3CF--------------
.1     CMP #$03     IN PAGE 3?
       BNE .2       NO
       LDA TRGT     BELOW $3D0?
       CMP #$D0
       BCC .4       YES, SAFE
       BCS .3       NO, NOT SAFE
  .DO AUXMEM
*---ALLOW $800-MACSTK------------
.2     CMP #$08     BELOW PAGE 8?
       BCC .3       YES, NOT SAFE
       LDA TRGT
       CMP MACSTK
       LDA TRGT+1
       SBC MACSTK+1
       BCC .4       BELOW MACSTK, SAFE
  .ELSE
*---ALLOW $800-MACLBL------------
.2     CMP #$08     BELOW PAGE 8?
       BCC .3       YES, NOT SAFE
       LDA TRGT     NO, COMPARE TO MACLBL
       CMP MACLBL
       LDA TRGT+1
       SBC MACLBL+1
       BCC .4       BELOW MACLBL, SO SAFE
*---ALLOW EOT-MACSTK-------------
       LDA EOT
       CMP TRGT
       LDA EOT+1
       SBC TRGT+1
       BCS .3       BELOW EOT, NOT SAFE
       LDA TRGT
       CMP MACSTK
       LDA TRGT+1
       SBC MACSTK+1
       BCC .4       BELOW MACSTK, SAFE
  .FIN
*---NOT SAFE, CHECK USER RANGE---
.3     LDA TRGT
       CMP USER.MEM.LO
       LDA TRGT+1
       SBC USER.MEM.LO+1
       BCC .5       DEFINITELY OUT OF BOUNDS
       LDA USER.MEM.HI
       CMP TRGT
       LDA USER.MEM.HI+1
       SBC TRGT+1
       BCC .5       DEFINITELY OUT OF BOUNDS
.4     LDY #0
       LDA OBJ.BYTE
       STA (TRGT),Y
       RTS
.5     LDY #QMEMPRO
       JMP FIRM.ERROR
*--------------------------------
*    LIST SOURCE LINE
*--------------------------------
LIST.SOURCE.IF.LISTING
       JSR CHECK.IF.LISTING
LIST.SOURCE.REGARDLESS
       JSR P.MARGIN   PRINT BLANKS TILL MARGIN
LIST.SOURCE.AT.MARGIN
       JSR CONVERT.LINE.NUMBER.PRINT
       LDY MACRO.LEVEL
       BEQ .2
       LDA #'>'
.1     JSR CHO
       DEY
       BNE .1       ...UNTIL Y=0
.2     LDA #' '     ...NOW Y=0
.3     JSR CHO
       INY
       LDA WBUF-1,Y
       BNE .3
       RTS
*--------------------------------
*      PRINT CRLF IF IN PASS 2 AND IF LISTING IS ON
*--------------------------------
CRLF.CAUSED.FORM.FEED
       JSR FORM.FEED
CRLF.IF.LISTING
       JSR CHECK.IF.LISTING
CRLF.WITH.PAGING
       JSR CRLF
       INC LINE.COUNT
       LDA PAGE.LENGTH
       BEQ .1       ...NOT TITLING
       CMP LINE.COUNT
       BCC CRLF.CAUSED.FORM.FEED   ...END OF PAGE
.1     RTS
*--------------------------------
*    PROCESS LABEL DEFINITION
*--------------------------------
LABL   JSR PACK     PACK AND CHECK SYMBOL
       BCC ERR.BS   BAD SYMBOL
       JSR STSRCH   SEE IF DEFINED
       BCC ERR.DD   YES, DOUBLE DEFINITION
       JMP STADD    ADD TO SYMBOL TABLE
*--------------------------------
ERR.DD LDY PASS     ERROR IN PASS 1
       BEQ ERR.DBLDF     OK IN PASS 2
       LDY #6       SET FLAG FOR TESTING FWD REFS
       >SYM LDA,STPNTR
       ORA #$40
       >SYM STA,STPNTR
       LDY WBUF     LOOK AT COLUMN 1
       CPY #':      IF PRIVATE LABEL...
       BEQ .2       ...THEN DON'T UPDATE C.M.LABEL
       LDA STPNTR   SAVE POINTER TO THIS MAJOR LABEL
       STA CURRENT.MAJOR.LABEL
       LDA STPNTR+1
       STA CURRENT.MAJOR.LABEL+1
.2     RTS
ERR.DBLDF
       LDY #QER4    DOUBLE DEFN
       .HS 2C       SKIP 2 BYTES
ERR.BS LDY #QER7    BAD SYMBOL
       JMP SOFT.ERROR
*--------------------------------
*   Search Compressed Opcode Table
*      If carry clear, (Y,A) = address of table
*      If carry set, continue searching same table
*
*   Return with carry set if found, else carry clear.
*      (OPTBL.PNTR),Y points at 16-bit value
*                     of entry which matched.
*--------------------------------
SEARCH.COMPRESSED.TABLE
       BCS .6       ...Continue searching same table
       STA OPTBL.PNTR
       STY OPTBL.PNTR+1
*---Try matching 2nd letter------
       LDY #0
.1     LDA (OPTBL.PNTR),Y      Possible match
       ORA #$40                Make it ASCII
       CMP SEARCH.KEY+1        same as 2nd letter?
       BEQ .6                  ...yes, matched.
       BNE .3                  ...no
*---Scan to next 8-bit entry-----
.2     INY
       INY
.3     INY
       LDA (OPTBL.PNTR),Y
       BMI .2       ...another 24-bit entry
       ASL          check if beyond our sub-group
       BPL .1       ...no, valid 2nd letter option
.4     CLC          ...no match in table, carry clear
       RTS
*---Try matching 3rd letter------
.5     INY
.6     INY
       LDA (OPTBL.PNTR),Y
       BPL .4            ...no more options, not in table
       INY               point at data
       EOR #$C0          make like ASCII
       CMP SEARCH.KEY+2  compare to 3rd letter
       BNE .5            ...did not match, try another
       RTS               ...found it, return carry set
*--------------------------------------
MAN
SAVE usr/src/scmasm.31/scmasm.s.asmgen
LOAD usr/src/scmasm.31/scmasm.s
ASM