Digital-Research-Source-Code/MPM OPERATING SYSTEMS/MPM-86/MPM-86 2.0 SOURCES/10/OUTP.PLM

$title ('HEX OUTPUT MODULE')
hexout:
do;

/*

  modified  3/28/81  R. Silberstein
  modified  3/30/81  R. Silberstein
  modified  4/9/81   R. Silberstein

*/

/*
        This is the module to produce the (hex-)output
        from the assembler. The interface to other modules
        goes through the subroutine

               EMITCODEBYTE (outputbyte,segmenttype).

        This routine outputs one byte of generated code of
        a specified segment type (code,data,stack,extra).

        The subroutine also updates the value of the current
        instruction pointer of the current segment (CIP),
        and prints the output code on the print line.
*/

$include (:f1:macro.lit)
$include (:f1:struc.lit)
$include (:f1:outp.lit)
$include (:f1:subr2.ext)
$include (:f1:files.ext)
$include (:f1:global.ext)


dcl
empty       lit '0ffh',  /* buffer empty value */
recordlimit lit '30',    /* max no of bytes pr record */
loccip      addr,        /* local copy of instruction pointer */
startfound  byte,        /* true if start record sent */
gtyp        byte,        /* incomming byte type */
gbyt        byte,        /* incomming byte */
curtyp      byte,        /* current byte type */
sum         byte,        /* used to compute check sum */
buffer (35) byte,        /* record buffer (RECORDLIMIT+5) */
recordlg    byte at (.buffer(0)),
recordtype  byte at (.buffer(3)),
offsetaddr  addr at (.buffer(1)),
bufpt       byte,        /* buffer index */

       /* Record type conversion table */
       /*   ( to be changed later ??? ) */

rectyp$I$tab(12) byte data

  (0ffh,eoftype,0ffh,starttype,INTELdata,INTELdata,
   INTELdata,INTELdata,INTELsegment,INTELsegment,INTELsegment,
   INTELsegment),

rectyp$D$tab(12) byte data

  (0ffh,eoftype,0ffh,starttype,DRcodedata,DRdatadata,
   DRstackdata,DRextradata,DRcodesegm,DRdatasegm,DRstacksegm,
   DRextrasegm);


/*********** subroutines **********/

rectyptab: procedure(n) byte;
  declare n byte;
  if intel$hex$on then$do
    return rectyp$I$tab(n);
  else$do
    return rectyp$D$tab(n);
  end$if;
end rectyptab;

switch$high$low: procedure(p);
  declare p address, ch based p byte, (s1,s2) byte;
  s1=ch;
  p=p+1;
  s2=ch;
  ch=s1;
  p=p-1;
  ch=s2;
end switch$high$low;

writebyt: proc (ch);
  dcl ch byte;
  call outhexbyte(ch);
end writebyt;

writerecord: proc;  /* write current recor to file */
  call switch$high$low(.offsetaddr);
  recordlg=bufpt-4;
  sum=0;              /* compute check sum */
  i=0ffh;
  do while (i:=i+1) < bufpt;
    sum=sum+buffer(i);
  end$while;
  buffer(bufpt)=-sum;  /* check sum */
  call writebyt(':');
  do i=0 to bufpt;     /* print hexbytes to file */
    call hex1out(buffer(i),.help(0));
    call writebyt(help(0));
    call writebyt(help(1));
  end$do;
  call writebyt(cr);
  call writebyt(lf);
end writerecord;

enternewbyt: proc(b); /* enter a new byte into buffer */
  dcl b byte;
  if bufpt > recordlimit then$do /* test if record full */
    call writerecord;
    offsetaddr=cip;
    bufpt=4;
  end$if;
  buffer(bufpt)=b;
  bufpt=bufpt+1;
end enternewbyt;

enterinput: proc;
  call enternewbyt(gbyt);
end enterinput;

eofrecord: proc;   /* write end-of-file record to file */
  if curtyp<>empty then call writerecord;
  recordtype=rectyptab(eoftype);
  offsetaddr=0;
  bufpt=4;
  call writerecord;
end eofrecord;

startrecord: proc;  /* write a start record to file */
  dcl seglow byte at (.csegvalue),seghigh byte at (.csegvalue+1),
      offslow byte at (.cip),offshigh byte at (.cip+1);
  if pass=2 then$do
    startfound=true;
    if curtyp <> empty then call writerecord;
    bufpt=4;
    offsetaddr=0;
    recordtype=rectyptab(starttype);
    if csegspec then$do
      call enternewbyt(seghigh);
      call enternewbyt(seglow);
    else$do
      call enternewbyt(0);
      call enternewbyt(0);
    end$if;
    call enternewbyt(offshigh);
    call enternewbyt(offslow);
    call writerecord;
    curtyp=empty;
  end$if;
end startrecord;

segmbyte: proc;  /* write a segment value byte to file */
  if pass = 2 then$do
    if curtyp <> gtyp then$do
      if curtyp <> empty then call writerecord;
      curtyp=gtyp;
      recordtype=rectyptab(gtyp);
      offsetaddr=0;
      bufpt=4;
      call enterinput;
    else$do
      call enterinput;
      call writerecord;
      curtyp=empty;
    end$if;
  end$if;
end segmbyte;

databyte: proc;  /* write a data byte to file */
  if pass=2 then$do
    if (curtyp <> gtyp) or (loccip <> cip) then$do
      if curtyp<>empty then call writerecord;
      curtyp=gtyp;
      recordtype=rectyptab(gtyp);
      offsetaddr=cip;
      bufpt=4;
    end$if;
    call enterinput;
    call hex1out(gbyt,.prefix(prefixptr)); /* output to listing */
    prefixptr=prefixptr+2;
  end$if;
  cip=cip+1;   /* update instruction pointer */
  loccip=cip;
end databyte;

emitinit: proc public;
  startfound=false;
  curtyp=empty;
end emitinit;

emitterminate: proc public;
  call eofrecord;  /* write EOF record */
end emitterminate;

emitcodebyte: proc (b,typ) public;
  dcl (b,typ) byte;
  gbyt=b;  /* move to global variables */
  gtyp=typ;

  do case typ-CSdata;

    do;               /* CS data */
    if not startfound then$do
      call startrecord;
    end$if;
    call databyte;
    end;
    call databyte;   /* DS data */
    call databyte;   /* SS data */
    call databyte;   /* ES data */
    call segmbyte;   /* CS value */
    call segmbyte;   /* DS value */
    call segmbyte;   /* SS value */
    call segmbyte;   /* ES value */

  end$case;

end emitcodebyte;

end$module hexout;