perm filename PASS3.SAI[OLD,HE] blob sn#501019 filedate 1980-03-25 generic text, type C, neo UTF8
COMMENT ⊗   VALID 00022 PAGES
C REC  PAGE   DESCRIPTION
C00001 00001
C00003 00002	IFCR ¬DECLARATION(EXTENDED_COMPILATION)
C00005 00003	!  Declarations, overall description
C00008 00004	!  EMITOFFSET, EMITSMLBLK
C00011 00005	!  EMITSUBS, EMITARGS, EMITCALL, PRINT_LIST
C00015 00006	!  EMITEXPR:  ONEARG, TWOARGS, THREEARGS
C00019 00007	!  EMITEXPR:  variable, constant
C00026 00008	!  EMITEXPR:  expression
C00035 00009	!  EMITBOOL
C00037 00010	!  ENV_SIZE
C00040 00011	!  TSCAN:  STMNT, PROG
C00045 00012	!  TSCAN:  BLOCK
C00058 00013	!  TSCAN:  BLOCK continued
C00067 00014	!  TSCAN:  COBLOCK
C00070 00015	!  TSCAN:  FORR, WHIL, UNTL, IFF, CASE, PAUSE, PROMPT, ABORT
C00078 00016	!  TSCAN:  ASSIGNMENT, PRNT, CALL, RETURN
C00081 00017	!  TSCAN:  CMON, CMABLE
C00083 00018	!  TSCAN:  MOVE$, OPERATE, CENTER, RETRY, STOP, SETBASE, WRIST
C00104 00019	!  TSCAN:  COMMENT, AFFIX, UNFIX
C00108 00020	!  TSCAN:  EVDO
C00110 00021	!  UNRECOGNIZED
C00111 00022	!  Bugs
C00112 ENDMK
C⊗;
IFCR ¬DECLARATION(EXTENDED_COMPILATION)
THENC
    ENTRY;
    BEGIN "PASS3"

IFCR ¬DECLARATION(CREFFING) THENC DEFINE CREFFING = "FALSE"; ENDC
IFCR ¬ CREFFING THENC
    COMMENT:  Source file requirements;
    REQUIRE "ABBREV.SAI[AL,HE]" SOURCE_FILE;
    REQUIRE "RECAUX.HDR[AL,HE]" SOURCE_FILE;
    REQUIRE "ARITH.HDR[AL,HE]" SOURCE_FILE ;
    REQUIRE "ALREC.SAI[AL,HE]" SOURCE_FILE ;
ENDC
    REDEFINE $$PRGID "[]" = ["PASS3"];
IFCR CREFFING THENC REQUIRE $$PRGID MESSAGE; ENDC
    REQUIRE "EMITER.HDR[AL,HE]" SOURCE_FILE;
    REQUIRE "INTDEF.SAI[AL,HE]" SOURCE_FILE;
ENDC

REQUIRE "EMITER.REL[AL,HE]" LOAD_MODULE;
    ! Standard emitter;

!  Declarations, overall description;

RCELL USEDVARS; ! A list of variables as they appear.  Used to
generate the needed list of graph node calculators;

!  The word that heads a constant gives its type. (These are also used
by MVAR.) These are they:;

DEFINE SCLID = 1;
DEFINE VCTID = 2;
DEFINE TRNID = 3;
DEFINE EVTID = 4;
DEFINE CMNID = 5;
DEFINE ARYID = '1000;
DEFINE PROID = '4000;
DEFINE REFID = '2000;	! for procedure arguments;

!  This file contains all the routines necessary for implementing the
third pass of AL, that is, the code generator.

The principal routine is TSCAN, which generates code for the root of
the bound parse tree and calls itself recursively for the rest.  The
structures in this tree are defined in ALREC[AL,HE], page three.
TSCAN is a large IF-THEN-ELSE-IF-THEN chain which determines which of
the various possible structures is present.  If it is some kind of
statement, then appropriate pseudo-code is emitted.  The preparation
of this code may require that code for the evaluation of an
expression.  Such code is prepared in the recursive procedure
EMITEXPR, which performs type-consistency checking (but not constant
folding, which could be done here).  Code for boolean tests is
prepared by EMITBOOL.

All code emission is done through the routine EMIT, to be found in
EMITER.SAI, which takes arguments specifying what output file to use
(e.g., pseudo-code or constant area), the data to output, and whether
to treat it as an instruction, an octal constant, a label
declaration, or repeatedly to produce the rel file.  ;
!  EMITOFFSET, EMITSMLBLK;

INTERNAL PROCEDURE EMITOFFSET(INTEGER PC;RANY VARBL);
    BEGIN "emitoffset"
    !  Outputs into the file PC the offset of VARBL, making a remark;
    INTEGER DUMY;
    IF RECTYPE(VARBL) = LOC(EXPRN) THEN VARBL ← CELL:CAR[EXPRN:ARGS[VARBL]];
    MAKE_REMARK(PC,VARIABLE:NAME[VARBL]);
    EMIT(PC,VARIABLE:OFFSET[VARBL],CONST);
    END "emitoffset";

INTEGER PROCEDURE EMITSMLBLK
	(INTEGER LENGTH; REFERENCE REAL FIRST_ELT; BOOLEAN REF (FALSE));
    BEGIN "emitsmlblk"
    !  Emits a constant in the small block area.  The length is
    given, as is the first element, so that the whole thing can be
    grabbed by location.  Note that LENGTH must not be greater than
    3.	The label of the block is returned as the result if REF is
    true, otherwise, no label is emitted.
    ;
    OWN INTEGER ARRAY DATA [1:4];  ! maxlength + 1 long;
    INTEGER ARRAY RELOC [1:4];
    INTEGER J, ADDR, K;

    IF LENGTH > 3
    THEN BEGIN
	COMERR("EMITSMLBLK cannot handle length = " & CVS(LENGTH));
	LENGTH ← 3;
	END;
    IF REF
    THEN BEGIN
	DATA[1] ← GENLABEL;
	RELOC[1] ← SYMDEC;
	K ← 2;
	END
    ELSE K ← 1;   !  Place for next entry in DATA, RELOC;
    ADDR ← LOC(FIRST_ELT);
    FOR J ← 0 STEP 1 UNTIL LENGTH-1 DO
	BEGIN "stuff";
	DATA[K] ← MEM[ADDR + J,INTEGER];
	RELOC[K] ← FLOAT;
	K ← K + 1;
	END "stuff";
    EMIT(SMLBLK,DATA[1],RELOC[1],K-1);
    RETURN(IF REF THEN DATA[1] ELSE -1);
    END "emitsmlblk";
!  EMITSUBS, EMITARGS, EMITCALL, PRINT_LIST;

FORWARD INTERNAL RECURSIVE INTEGER PROCEDURE EMITEXPR 
					(REXPR XPRESS;BOOLEAN GET(TRUE));

RECURSIVE PROCEDURE EMITSUBS(RCELL C);
	BEGIN ! place subscripts on stack;
	IF C = RNULL THEN RETURN;
	EMITSUBS(CELL:CDR[C]);
	EMITEXPR(CELL:CAR[C])
	END;

RECURSIVE PROCEDURE EMITARGS(RCELL A);
	BEGIN ! puts expressions on stack;
	IF A = RNULL THEN RETURN;
	EMITARGS(CELL:CDR[A]);
	IF RECTYPE(CELL:CAR[A]) = LOC(EXPRN) THEN
	    IF EXPRN:OP[CELL:CAR[A]] = AREF_OP THEN ! put subscripts on stack;
		EMITSUBS(CELL:CDR[EXPRN:ARGS[CELL:CAR[A]]])
	    ELSE EMITEXPR(CELL:CAR[A]) ! put expression on stack;
	END;

RECURSIVE INTEGER PROCEDURE EMITCALL(REXPR E);
	BEGIN ! generates code for a procedure call;
	RCELL C;
	C ← EXPRN:ARGS[E];
	EMITARGS(CELL:CDR[C]); ! put any expressions on stack;
	EMIT(PSDCODE,PROC_PSOP,PSINST); ! generate the procedure call;
	EMITOFFSET(PSDCODE,LLOP(C));
	WHILE C ≠ RNULL DO ! now generate the argument list;
		BEGIN
		IF RECTYPE(CELL:CAR[C]) = LOC(EXPRN)
		     ∧ EXPRN:OP[CELL:CAR[C]] ≠ AREF_OP THEN
			EMIT(PSDCODE,'177777,CONST) ! expr's value is on stack;
		ELSE EMITEXPR(CELL:CAR[C],FALSE); ! give offset/address;
		C ← CELL:CDR[C]
		END;
	RETURN(PROCDEF:DATATYPE[CELL:CAR[EXPRN:ARGS[E]]])
	END;

RECURSIVE PROCEDURE PRINT_LIST(RCELL C);
	BEGIN
	INTEGER LAB;
	IF C ≠ RNULL THEN MAKE_REMARK(PSDCODE,"Print");
	WHILE C ≠ RNULL DO
	    BEGIN "print list"
	    IF RECTYPE(CELL:CAR[C]) = LOC(STCONST)
	    THEN BEGIN "prntstr"
		INTEGER ADR;
		ADR ← LOC(STCONST:VAL[CELL:CAR[C]]);
		LAB ← GENLABEL;
		EMIT(SMLBLK,LAB,SYMDEC);
		EMIT(SMLBLK,ADR,STRCONST);
		EMIT(PSDCODE,PRINT_PSOP,PSINST);
		EMIT(PSDCODE,LAB,SYMREF);
		END "prntstr"
	    ELSE BEGIN "prntexpr"
		!  Get the value on the stack;
		EMITEXPR(CELL:CAR[C]);
		EMIT(PSDCODE,VALPRN_PSOP,PSINST);
		END "prntexpr";
	    C ← CELL:CDR[C];
	    END "print list"
	END;

!  EMITEXPR:  ONEARG, TWOARGS, THREEARGS;

INTERNAL RECURSIVE INTEGER PROCEDURE EMITEXPR (REXPR XPRESS;BOOLEAN GET(TRUE));
    ! Emits code for XPRESS, the value of which is to be left at top
    of stack, returns the type of the expression. FRAME_DTYPE is
    never returned.  It is coerced to TRANS_DTYPE;

    BEGIN "emitexpr"
    INTEGER RTYPE, DTYPE;

    RECURSIVE PROCEDURE ONEARG(INTEGER ARG1TYPE,OPERATION,RESTYPE);
	BEGIN  ! Pick up one argument, evaluate;
	REXPR XXX;
	XXX ← XPRESS; ! because of a SAIL Bug;
	MAKE_REMARK(PSDCODE,"first argument");
	IF EMITEXPR(CELL:CAR[EXPRN:ARGS[XXX]]) ≠ ARG1TYPE
	THEN COMERR("Wrong type of argument",XXX);
	EMIT(PSDCODE,OPERATION,PSINST);
	DTYPE ← RESTYPE;
	END;

    RECURSIVE PROCEDURE TWOARGS
	(INTEGER ARG1TYPE,ARG2TYPE,OPERATION,RESTYPE);
	BEGIN  ! Pick up two arguments, evaluate them;
	REXPR XXX;
	XXX ← XPRESS; ! because of a SAIL Bug;
	MAKE_REMARK(PSDCODE,"first argument");
	IF EMITEXPR(CELL:CAR[EXPRN:ARGS[XXX]]) ≠ ARG1TYPE
	THEN COMERR("Wrong type for first argument",XXX);
	MAKE_REMARK(PSDCODE,"second argument");
	IF EMITEXPR(CADR(EXPRN:ARGS[XXX])) ≠ ARG2TYPE
	THEN COMERR("Wrong type for second argument",XXX);
	EMIT(PSDCODE,OPERATION,PSINST);
	DTYPE ← RESTYPE;
	END;

    RECURSIVE PROCEDURE THREEARGS
	(INTEGER ARG1TYPE,ARG2TYPE,ARG3TYPE,OPERATION,RESTYPE);
	BEGIN  ! Pick up three arguments, evaluate;
	REXPR XXX;
	XXX ← XPRESS; ! because of a SAIL Bug;
	MAKE_REMARK(PSDCODE,"first argument");
	IF EMITEXPR(CELL:CAR[EXPRN:ARGS[XXX]]) ≠ ARG1TYPE
	THEN COMERR("Wrong type for first argument",XXX);
	MAKE_REMARK(PSDCODE,"second argument");
	IF EMITEXPR(CADR(EXPRN:ARGS[XXX])) ≠ ARG2TYPE
	THEN COMERR("Wrong type for second argument",XXX);
	MAKE_REMARK(PSDCODE,"third argument");
	IF EMITEXPR(CADDR(EXPRN:ARGS[XXX])) ≠ ARG3TYPE
	THEN COMERR("Wrong type for third argument",XXX);
	EMIT(PSDCODE,OPERATION,PSINST);
	DTYPE ← RESTYPE;
	END;
!  EMITEXPR:  variable, constant;

    PRELOAD_WITH PUSH_PSOP, DUMMY;
	OWN INTEGER ARRAY DATA[0:1];
    PRELOAD_WITH PSINST, SYMREF;
	OWN INTEGER ARRAY RELOC [0:1];

    ! To emit constants but once a list of already emitted constants is kept;

    RECORD_CLASS CONLST(RPTR(SVAL,V3ECT,ROTN,TRANS) VAL; INTEGER LAB;
				RPTR(CONLST) NEXT);
    OWN RPTR(CONLST) SVAL_HDR,V3ECT_HDR,ROTN_HDR,TRANS_HDR;
    RPTR(CONLST) PTR;

    INTEGER LAB;

    RTYPE ← RECTYPE(XPRESS);

    !  A variable?;
    IF RTYPE = LOC(VARIABLE) ∨ RTYPE = LOC(ARRAYDEF)
    THEN BEGIN "variable"
	IF GET THEN EMIT(PSDCODE,GTVAL_PSOP,PSINST);
	EMITOFFSET(PSDCODE,XPRESS);
	DTYPE ← VARIABLE:DATATYPE[XPRESS];
	USEDVARS ← CONS(XPRESS,USEDVARS);
	END "variable"

    !  A constant?;
    ELSE IF RTYPE = LOC(SVAL)
    THEN BEGIN "scalar"
	PTR ← SVAL_HDR;		! Check if it's already been emitted;
	WHILE PTR ≠ RNULL DO
	    IF SVAL:VAL[XPRESS] = SVAL:VAL[CONLST:VAL[PTR]] THEN DONE
		ELSE PTR ← CONLST:NEXT[PTR];
	IF PTR = RNULL THEN
	    BEGIN		! Emit the scalar & add it to the conlst;
	    EMIT(SMLBLK,SCLID,CONST); ! Header for typing;
	    LAB ← EMITSMLBLK(1,SVAL:VAL[XPRESS],TRUE);
	    PTR ← NEW_RECORD(CONLST);
	    CONLST:VAL[PTR] ← XPRESS;
	    CONLST:LAB[PTR] ← LAB;
	    CONLST:NEXT[PTR] ← SVAL_HDR;
	    SVAL_HDR ← PTR;
	    END
	ELSE LAB ← CONLST:LAB[PTR];
	DATA[1] ← LAB;
	IF GET THEN EMIT(PSDCODE,DATA[0],RELOC[0],2)
	       ELSE EMIT(PSDCODE,LAB,SYMREF);
	DTYPE ← SVAL_DTYPE;
	END "scalar"
    ELSE IF RTYPE = LOC(V3ECT)
    THEN BEGIN "vector"
	PTR ← V3ECT_HDR;		! Check if it's already been emitted;
	WHILE PTR ≠ RNULL DO
	    IF V3CMP(XPRESS,CONLST:VAL[PTR]) THEN PTR ← CONLST:NEXT[PTR]
		ELSE DONE;
	IF PTR = RNULL THEN
	    BEGIN		! Emit the vector & add it to the conlst;
	    EMIT(SMLBLK,VCTID,CONST); ! Header for typing;
	    LAB ← EMITSMLBLK(3,V3ECT:X[XPRESS],TRUE);
	    EMITSMLBLK(1,1.0); ! This puts the scale factor in;
	    PTR ← NEW_RECORD(CONLST);
	    CONLST:VAL[PTR] ← XPRESS;
	    CONLST:LAB[PTR] ← LAB;
	    CONLST:NEXT[PTR] ← V3ECT_HDR;
	    V3ECT_HDR ← PTR;
	    END
	ELSE LAB ← CONLST:LAB[PTR];
	DATA[1] ← LAB;
	IF GET THEN EMIT(PSDCODE,DATA[0],RELOC[0],2)
	       ELSE EMIT(PSDCODE,LAB,SYMREF);
	DTYPE ← V3ECT_DTYPE;
	END "vector"
    ELSE IF RTYPE = LOC(ROTN)
    THEN BEGIN "rot"  !  Will output the equivalent trans;
	PTR ← ROTN_HDR;		! Check if it's already been emitted;
	WHILE PTR ≠ RNULL DO
	    IF ROTCMP(XPRESS,CONLST:VAL[PTR]) THEN PTR ← CONLST:NEXT[PTR]
		ELSE DONE;
	IF PTR = RNULL THEN
	    BEGIN		! Emit the rotn & add it to the conlst;
	    EMIT(SMLBLK,TRNID,CONST); ! Header for typing;
	    LAB ← EMITSMLBLK(3,ROTN:RMX[XPRESS][1,1],TRUE);
	    EMITSMLBLK(3,ROTN:RMX[XPRESS][2,1]);
	    EMITSMLBLK(3,ROTN:RMX[XPRESS][3,1]);
	    EMITSMLBLK(3,V3ECT:X[NILVECT]);  ! The fourth column;
	    PTR ← NEW_RECORD(CONLST);
	    CONLST:VAL[PTR] ← XPRESS;
	    CONLST:LAB[PTR] ← LAB;
	    CONLST:NEXT[PTR] ← ROTN_HDR;
	    ROTN_HDR ← PTR;
	    END
	ELSE LAB ← CONLST:LAB[PTR];
	DATA[1] ← LAB;
	IF GET THEN EMIT(PSDCODE,DATA[0],RELOC[0],2)
	       ELSE EMIT(PSDCODE,LAB,SYMREF);
	DTYPE ← ROTN_DTYPE;
	END "rot"
    ELSE IF RTYPE = LOC(TRANS)
    THEN BEGIN "trans"
	PTR ← TRANS_HDR;		! Check if it's already been emitted;
	WHILE PTR ≠ RNULL DO
	    IF TRANSCMP(XPRESS,CONLST:VAL[PTR]) THEN PTR ← CONLST:NEXT[PTR]
		ELSE DONE;
	IF PTR = RNULL THEN
	    BEGIN		! Emit the trans & add it to the conlst;
	    EMIT(SMLBLK,TRNID,CONST); ! Header for typing;
	    LAB ← EMITSMLBLK(3,ROTN:RMX[TRANS:R[XPRESS]][1,1],TRUE);
	    EMITSMLBLK(3,ROTN:RMX[TRANS:R[XPRESS]][2,1]);
	    EMITSMLBLK(3,ROTN:RMX[TRANS:R[XPRESS]][3,1]);
	    EMITSMLBLK(3,V3ECT:X[TRANS:P[XPRESS]]);  ! The fourth column;
	    PTR ← NEW_RECORD(CONLST);
	    CONLST:VAL[PTR] ← XPRESS;
	    CONLST:LAB[PTR] ← LAB;
	    CONLST:NEXT[PTR] ← TRANS_HDR;
	    TRANS_HDR ← PTR;
	    END
	ELSE LAB ← CONLST:LAB[PTR];
	DATA[1] ← LAB;
	IF GET THEN EMIT(PSDCODE,DATA[0],RELOC[0],2)
	       ELSE EMIT(PSDCODE,LAB,SYMREF);
	DTYPE ← TRANS_DTYPE;
	END "trans"
    ELSE IF RTYPE = LOC(FRAME)
	THEN BEGIN "frame"  ! Recursive call to pick up the trans inside;
	EMITEXPR(FRAME:VAL[XPRESS],GET);
	DTYPE ← FRAME_DTYPE;
	END "frame"
!  EMITEXPR:  expression;

    !  An expression?;
    ELSE IF RTYPE = LOC(EXPRN)
    THEN BEGIN "recurse"
	INTEGER OPR;
	OPR ← EXPRN:OP[XPRESS];
	IF OPR < 0 ∨ OPR ≥ LAST_OP
	THEN BEGIN
	    COMERR("Illegal expression",XPRESS);
	    DTYPE ← 0;
	    END
	ELSE CASE OPR OF
	    BEGIN "case"
 [NO_OP]	DTYPE ← EMITEXPR(CELL:CAR[EXPRN:ARGS[XPRESS]]);
 [SCALRD_OP]	BEGIN
		EMIT(PSDCODE,SCALRD_PSOP,PSINST);
		DTYPE ← SVAL_DTYPE
		END;
 [QUERY_OP]	BEGIN
		PRINT_LIST(EXPRN:ARGS[XPRESS]);  ! Take care of any print items;
		EMIT(PSDCODE,QUERY_PSOP,PSINST);
		DTYPE ← SVAL_DTYPE
		END;
 [SABS_OP]	ONEARG(SVAL_DTYPE,SABS_PSOP,SVAL_DTYPE);
 [SADD_OP]	TWOARGS(SVAL_DTYPE,SVAL_DTYPE,SADD_PSOP,SVAL_DTYPE);
 [SNEG_OP]	ONEARG(SVAL_DTYPE,SNEG_PSOP,SVAL_DTYPE);
 [SSUB_OP]	TWOARGS(SVAL_DTYPE,SVAL_DTYPE,SSUB_PSOP,SVAL_DTYPE);
 [SMUL_OP]	TWOARGS(SVAL_DTYPE,SVAL_DTYPE,SMUL_PSOP,SVAL_DTYPE);
 [SDIV_OP]	TWOARGS(SVAL_DTYPE,SVAL_DTYPE,SDIV_PSOP,SVAL_DTYPE);
 [SEXP_OP]	TWOARGS(SVAL_DTYPE,SVAL_DTYPE,SEXP_PSOP,SVAL_DTYPE);
 [MAX_OP]	TWOARGS(SVAL_DTYPE,SVAL_DTYPE,MAX_PSOP,SVAL_DTYPE);
 [MIN_OP]	TWOARGS(SVAL_DTYPE,SVAL_DTYPE,MIN_PSOP,SVAL_DTYPE);
 [INT_OP]	ONEARG(SVAL_DTYPE,INT_PSOP,SVAL_DTYPE);
 [DIV_OP]	TWOARGS(SVAL_DTYPE,SVAL_DTYPE,IDIV_PSOP,SVAL_DTYPE);
 [MOD_OP]	TWOARGS(SVAL_DTYPE,SVAL_DTYPE,MOD_PSOP,SVAL_DTYPE);
 [SLT_OP]	TWOARGS(SVAL_DTYPE,SVAL_DTYPE,SLT_PSOP,SVAL_DTYPE);
 [SEQ_OP]	TWOARGS(SVAL_DTYPE,SVAL_DTYPE,SEQ_PSOP,SVAL_DTYPE);
 [SLE_OP]	TWOARGS(SVAL_DTYPE,SVAL_DTYPE,SLE_PSOP,SVAL_DTYPE);
 [SGE_OP]	TWOARGS(SVAL_DTYPE,SVAL_DTYPE,SGE_PSOP,SVAL_DTYPE);
 [SNE_OP]	TWOARGS(SVAL_DTYPE,SVAL_DTYPE,SNE_PSOP,SVAL_DTYPE);
 [SGT_OP]	TWOARGS(SVAL_DTYPE,SVAL_DTYPE,SGT_PSOP,SVAL_DTYPE);
 [AND_OP]	TWOARGS(SVAL_DTYPE,SVAL_DTYPE,AND_PSOP,SVAL_DTYPE);
 [OR_OP]	TWOARGS(SVAL_DTYPE,SVAL_DTYPE,LOR_PSOP,SVAL_DTYPE);
 [NOT_OP]	ONEARG(SVAL_DTYPE,NOT_PSOP,SVAL_DTYPE);
 [XOR_OP]	TWOARGS(SVAL_DTYPE,SVAL_DTYPE,LXOR_PSOP,SVAL_DTYPE);
 [EQV_OP]	TWOARGS(SVAL_DTYPE,SVAL_DTYPE,EQV_PSOP,SVAL_DTYPE);
 [VMAGN_OP]	ONEARG(V3ECT_DTYPE,VMAGN_PSOP,SVAL_DTYPE);
 [VDOT_OP]	TWOARGS(V3ECT_DTYPE,V3ECT_DTYPE,VDOT_PSOP,SVAL_DTYPE);
 [RMAGN_OP]	ONEARG(ROTN_DTYPE,TMAGN_PSOP,SVAL_DTYPE);
 [AXIS_OP]	ONEARG(ROTN_DTYPE,TAXIS_PSOP,V3ECT_DTYPE);
 [VMAKE_OP]	THREEARGS(SVAL_DTYPE,SVAL_DTYPE,SVAL_DTYPE,VMAKE_PSOP,V3ECT_DTYPE);
 [SVMUL_OP]	TWOARGS(SVAL_DTYPE,V3ECT_DTYPE,SVMUL_PSOP,V3ECT_DTYPE);
 [VSDIV_OP]	TWOARGS(V3ECT_DTYPE,SVAL_DTYPE,VSDIV_PSOP,V3ECT_DTYPE);
 [VADD_OP]	TWOARGS(V3ECT_DTYPE,V3ECT_DTYPE,VADD_PSOP,V3ECT_DTYPE);
 [VSUB_OP]	TWOARGS(V3ECT_DTYPE,V3ECT_DTYPE,VSUB_PSOP,V3ECT_DTYPE);
 [VCROSS_OP]	TWOARGS(V3ECT_DTYPE,V3ECT_DTYPE,VCROSS_PSOP,V3ECT_DTYPE);
 [RVMUL_OP]	TWOARGS(ROTN_DTYPE,V3ECT_DTYPE,TVMUL_PSOP,V3ECT_DTYPE);
 [TVMUL_OP]	TWOARGS(TRANS_DTYPE,V3ECT_DTYPE,TVMUL_PSOP,V3ECT_DTYPE);
 [UVECT_OP]	ONEARG(V3ECT_DTYPE,UNITV_PSOP,V3ECT_DTYPE);
 [POS_OP]	ONEARG(TRANS_DTYPE,TPOS_PSOP,V3ECT_DTYPE);
 [ORIENT_OP]	ONEARG(TRANS_DTYPE,TORIEN_PSOP,ROTN_DTYPE);
 [AXW_ROTN_OP]	TWOARGS(V3ECT_DTYPE,SVAL_DTYPE,VSAXWR_PSOP,ROTN_DTYPE);
 [TMAKE_OP]	TWOARGS(ROTN_DTYPE,V3ECT_DTYPE,TMAKE_PSOP,TRANS_DTYPE);
 [CONSTR_OP]	THREEARGS(V3ECT_DTYPE,V3ECT_DTYPE,V3ECT_DTYPE,CONSTR_PSOP,TRANS_DTYPE);
 [TVADD_OP]	TWOARGS(TRANS_DTYPE,V3ECT_DTYPE,TVADD_PSOP,TRANS_DTYPE);
 [TVSUB_OP]	TWOARGS(TRANS_DTYPE,V3ECT_DTYPE,TVSUB_PSOP,TRANS_DTYPE);
 [RRMUL_OP]	TWOARGS(ROTN_DTYPE,ROTN_DTYPE,TTMUL_PSOP,ROTN_DTYPE);
 [TTMUL_OP]	TWOARGS(TRANS_DTYPE,TRANS_DTYPE,TTMUL_PSOP,TRANS_DTYPE);
 [TINVRT_OP]	ONEARG(TRANS_DTYPE,TINVRT_PSOP,TRANS_DTYPE);
 [FTOF_OP]	BEGIN	! A→B ≡ INV(A)*B;
		ONEARG(TRANS_DTYPE,TINVRT_PSOP,TRANS_DTYPE);
		IF EMITEXPR(CADR(EXPRN:ARGS[XPRESS])) ≠ TRANS_DTYPE
		THEN COMERR("Wrong type for second argument",XPRESS);
		EMIT(PSDCODE,TTMUL_PSOP,PSINST);
		END;
 [DEPR_OP]	DTYPE ← EMITEXPR(CADR(EXPRN:ARGS[XPRESS]));
 [FMAKE_OP]	TWOARGS(ROTN_DTYPE,V3ECT_DTYPE,TMAKE_PSOP,TRANS_DTYPE);
 [SSBRTN_OP]	BEGIN
		  INTEGER OPTYPE;
		  IF (OPTYPE←SVAL:VAL[CELL:CAR[EXPRN:ARGS[XPRESS]]]) = ATAN2_OP
			THEN BEGIN
			  MAKE_REMARK(PSDCODE,"second argument");
			  IF EMITEXPR(CADDR(EXPRN:ARGS[XPRESS])) ≠ SVAL_DTYPE
				THEN COMERR("Wrong type of argument",XPRESS);
			END;
		  MAKE_REMARK(PSDCODE,"first argument");
		  IF EMITEXPR(CADR(EXPRN:ARGS[XPRESS])) ≠ SVAL_DTYPE
			THEN COMERR("Wrong type of argument",XPRESS);
		  EMIT(PSDCODE,SSBRTN_PSOP,PSINST);
		  MAKE_REMARK(PSDCODE,
		     CASE OPTYPE-1 OF ("sqrt","sin","cos","tan","asin","acos",
					"atan2","log","exp","time"));
		  EMIT(PSDCODE,OPTYPE,CONST);
		  DTYPE ← SVAL_DTYPE;
		END;
 [AREF_OP]	BEGIN
		  IF GET THEN
		    BEGIN
		    MAKE_REMARK(PSDCODE,"Array reference");
		    EMITSUBS(CELL:CDR[EXPRN:ARGS[XPRESS]]);
		    EMIT(PSDCODE,GTVAL_PSOP,PSINST)
		    END;
		  EMITOFFSET(PSDCODE,CELL:CAR[EXPRN:ARGS[XPRESS]]);
		  DTYPE ← ARRAYDEF:DATATYPE[CELL:CAR[EXPRN:ARGS[XPRESS]]]
		END;
 [CALL_OP]	DTYPE ← EMITCALL(XPRESS);
 [INVALID_OP]	COMERR("Invalid operator",XPRESS)
	    END "case";
	IF DTYPE ≠ EXPRN:DATATYPE[XPRESS] ∧
		( DTYPE ≠ TRANS_DTYPE  ∨  EXPRN:DATATYPE[XPRESS] ≠ FRAME_DTYPE )
	THEN COMERR("Type consistency error in EMITEXPR: " & CVS(DTYPE) &" ≠ " &
	    CVS(EXPRN:DATATYPE[XPRESS]) & ".",XPRESS);
	END "recurse"

    ELSE BEGIN
	COMERR("Garbage expression",XPRESS);
	DTYPE ← 0;
	END;

    IF DTYPE = FRAME_DTYPE THEN DTYPE ← TRANS_DTYPE;
    RETURN(DTYPE);
    END "emitexpr";
!  EMITBOOL;

PROCEDURE EMITBOOL(REXPR CONDITION; INTEGER DESTTRUE (0), DESTFALSE (0));
    BEGIN  "emitbool"
    !  Generates code to evaluate the condition.  If it succeeds,
    there should be a jump to DESTTRUE, if false, to DESTFALSE.  If
    either is 0, instead of jumping there, fall through;

    ! modified by arg 9-14-76;

    IF DESTFALSE
    THEN BEGIN "fjump"
	! Put the tested result on the stack;
	IF EMITEXPR(CONDITION) ≠ SVAL_DTYPE
	THEN COMERR("Non-scalar boolean",CONDITION);
	EMIT(PSDCODE,JUMPC_PSOP,PSINST,1); ! JUMPC;
	EMIT(PSDCODE,DESTFALSE,SYMREF,1);  ! (ref) DESTFALSE;
	IF DESTTRUE
	THEN BEGIN "tfjump"
	    EMIT(PSDCODE,JUMP_PSOP,PSINST,1);  !  JUMP;
	    EMIT(PSDCODE,DESTTRUE,SYMREF,1);  !  (ref) DESTTRUE;
	    END "tfjump"
	END "fjump"
    ELSE IF DESTTRUE
    THEN BEGIN "tjump"
	! Put the tested result on the stack;
	IF EMITEXPR(CONDITION) ≠ SVAL_DTYPE
	THEN COMERR("Non-scalar boolean",CONDITION);
	EMIT(PSDCODE,NOT_PSOP,PSINST,1);  ! Take the complement of the boolean;
	EMIT(PSDCODE,JUMPC_PSOP,PSINST,1);  ! JUMPC;
	EMIT(PSDCODE,DESTTRUE,SYMREF,1);  ! (ref) DESTTRUE;
	END "tjump";
    END "emitbool";
!  ENV_SIZE;

RECURSIVE INTEGER PROCEDURE ENV_SIZE(RANY BLK);
    BEGIN
    INTEGER SIZE,S;
    RANY P;

    IF (S ← RECTYPE(BLK)) = LOC(STMNT) THEN
	BEGIN
	BLK ← STMNT:SEMANTICS[BLK];
	IF BLK = RNULL THEN RETURN(0) ELSE S ← RECTYPE(BLK);
	END;

    IF S = LOC(BLOCK) THEN
	BEGIN "blk"
	SIZE ← 0;
	P ← BLOCK:VARS[BLK];
	WHILE P ≠ RNULL DO BEGIN SIZE ← SIZE + 1;	! Count algebraic vars;
				 P ← CELL:CDR[P] END;
	P ← BLOCK:ARAYS[BLK];
	WHILE P ≠ RNULL DO BEGIN SIZE ← SIZE + 1;	! Count arrays;
				 P ← CELL:CDR[P] END;
	P ← BLOCK:EVTS[BLK];
	WHILE P ≠ RNULL DO BEGIN SIZE ← SIZE + 1;	! Count events;
				 P ← CELL:CDR[P] END;
	P ← BLOCK:CMONS[BLK];
	WHILE P ≠ RNULL DO BEGIN SIZE ← SIZE + 1;	! Count cmons;
				 P ← CELL:CDR[P] END;
	P ← BLOCK:PROCS[BLK];
	WHILE P ≠ RNULL DO BEGIN SIZE ← SIZE + 1;	! Count procedures;
				 P ← CELL:CDR[P] END;
	S ← 0;
	P ← BLOCK:CODE[BLK];
	WHILE P ≠ RNULL DO S ← S MAX ENV_SIZE(LLOP(P));	! Check for nested blocks;
	RETURN(SIZE+S);
	END "blk"

    ELSE IF S = LOC(FORR) THEN RETURN(ENV_SIZE(FORR:BODY[BLK]))

    ELSE IF S = LOC(WHIL) THEN RETURN(ENV_SIZE(WHIL:BODY[BLK]))

    ELSE IF S = LOC(UNTL) THEN RETURN(ENV_SIZE(UNTL:BODY[BLK]))

    ELSE IF S = LOC(IFF) THEN
	 RETURN(ENV_SIZE(IFF:THN[BLK]) MAX ENV_SIZE(IFF:ELS[BLK]))

    ELSE IF S = LOC(KASE) THEN
	BEGIN
	S ← 0;
	P ← KASE:STMNTS[BLK];
	WHILE P≠RNULL DO S ← S MAX ENV_SIZE(LLOP(P)); ! check for nested blocks;
	RETURN(S)
	END

    ELSE RETURN(0);

    END;
!  TSCAN:  STMNT, PROG;

INTEGER OFS;  !  The current offset for variables;
INITIALIZE (OFS ← '400);	! Level 1, offset 0;
INTEGER RETRY_LAB;	! Label for retrying moves;

INTERNAL RECURSIVE PROCEDURE TSCAN (RANY PARSETREE);
    BEGIN "tscan"
    ! TSCAN takes a parse tree and interprets its nodes, calling
    appropriate routines to prepare code for each node;

    INTEGER STYP,  !  Statement type;
	LAB1, LAB2, LAB3, LAB4;
	    !  Save labels across recursive calls.  Cannot
	    save in DATA since that is an OWN array;
    RPTR(STMNT) STATEMENT;
    LABEL MIDLABEL, ENDLABEL;  !  This is to prevent parse stack overflow;

    STYP ← RECTYPE(PARSETREE);
    IF STYP = LOC(STMNT) THEN
	BEGIN "stmnt"
	!  Eventually will want to output labelling information here;
	STATEMENT ← PARSETREE;
	PARSETREE ← STMNT:SEMANTICS[PARSETREE];
	IF PARSETREE = RNULL THEN RETURN;
	STYP ← RECTYPE(PARSETREE);
	END "stmnt";

    IF STYP = LOC(VARIABLE) ∨ STYP = LOC(PVL) ∨ STYP = LOC(PAS)
	∨ STYP = LOC(S_FAC) ∨ STYP = LOC(NOTE1) ∨ STYP = LOC(DEPROACH) THEN
	!  Just ignore it.  Variable declarations are treated with
	block entry and exit. Others handled only during world modelling;
    ELSE IF STYP = LOC(NOTE) THEN
	PRINT(STCONST:VAL[NOTE:HESAYS[PARSETREE]],CRLF)
    ELSE IF STYP = LOC(NOTE2) THEN
	PRINT(STCONST:VAL[NOTE2:HESAYS[PARSETREE]],CRLF)

    ELSE IF STYP = LOC(PROG) THEN
	BEGIN "prog"

	MAKE_REMARK(PSDCODE,"Start of program");
	EMIT(PSDCODE,PROG_PSOP,PSINST);	!  Make mechanism variables;
	LAB4 ← ENV_SIZE(PROG:CODE[PARSETREE]);
	EMIT(PSDCODE,LAB4,CONST);	! Environment size needed by program;

	MAKE_REMARK(PSDCODE,"Initialization - AFFIX driver_grasp to driver_tip");
	EMITEXPR(NEW_TRANS(NILROTN,SVMUL(1.875,ZHAT)));
	EMIT(PSDCODE,AFFIX_PSOP,PSINST);
	EMITOFFSET(PSDCODE,DR_TIP);
	EMITOFFSET(PSDCODE,DR_GRASP);
	EMIT(PSDCODE,'2000,CONST); ! Explicitly named trans, rigid affixment, value on stack;
	EMITOFFSET(PSDCODE,DR_TRANS);

	MAKE_REMARK(PSDCODE,"Init (cont) - AFFIX moving_jaw to fixed_jaw");
	MAKE_REMARK(PSDCODE,"		Wait till VISE is ready");
!	EMITEXPR(NEW_EXPRN(TRANS_DTYPE,TMAKE_OP,LIST2(NILROTN,
		    NEW_EXPRN(V3ECT_DTYPE,SVMUL_OP,LIST2(VISE,YHAT)) )) );
!	EMIT(PSDCODE,AFFIX_PSOP,PSINST);
!	EMITOFFSET(PSDCODE,MOVING_JAW);
!	EMITOFFSET(PSDCODE,FIXED_JAW);
!	EMIT(PSDCODE,'2000,CONST); ! Explicitly named trans, rigid affixment, value on stack;
!	EMITOFFSET(PSDCODE,VISE_OPENING);
	MAKE_REMARK(PSDCODE,"End of Initialization");

	TSCAN(PROG:CODE[PARSETREE]);

	EMIT(PSDCODE,ENDP_PSOP,PSINST);  !  Clean up mechanism variables;
	MAKE_REMARK(PSDCODE,"End of program");
	CLOSEOUT;  ! Closes the output file;
	END "prog"
!  TSCAN:  BLOCK;

    ELSE IF STYP = LOC(BLOCK) THEN
	BEGIN "block"
	RCELL C;  !  Holds variable list and current tail of block;
	INTEGER DUMY, COFS, SAVOFS;  !	Holds OFS for the duration;
	INTEGER CNT, CTYPE, T, BITS;
	RVAR VARBL;  !	Temporary: variable under consideration;
	RANY F,P;
	RPTR(CMON) MONITOR;  !	Temporary: cmon under consideration;
	RCLASS COLAB (INTEGER LBEL; RPTR(COLAB) NEXT);
	RPTR (COLAB) LABELS, HERE;

	INTEGER PROCEDURE TYPE_GET(INTEGER DTYPE);
	    CASE DTYPE OF
		BEGIN
 [SVAL_DTYPE]	RETURN(SCLID);
 [V3ECT_DTYPE]	RETURN(VCTID);
 [ROTN_DTYPE] [TRANS_DTYPE] [FRAME_DTYPE] RETURN(TRNID);
 [EVENT_DTYPE]	RETURN(EVTID);
     ELSE	RETURN(0)
		END;

	INTEGER PROCEDURE VAR_CNT(INTEGER DTYPE);
	    BEGIN	! Count & assign offsets to all variables of specified type;
	    INTEGER CNT;
	    C ← BLOCK:VARS[PARSETREE];
	    CNT ← 0;
	    WHILE C ≠ RNULL DO
		BEGIN
		VARBL ← LLOP(C);
		IF VARIABLE:DATATYPE[VARBL] = DTYPE THEN
		    BEGIN
		    CNT ← CNT + 1;
		    VARIABLE:OFFSET[VARBL] ← OFS;
		    EMITOFFSET(SYMFIL,VARBL);
		    OFS ← OFS + 1;
		    END;
		END;
	    RETURN(CNT)
	    END;

	MAKE_REMARK(PSDCODE,"BLOCK");

	SAVOFS ← OFS;  !  We will assign new offsets in this block.;

	IF BLOCK:VARS[PARSETREE] ≠ RNULL ∨ BLOCK:ARAYS[PARSETREE] ≠ RNULL ∨
	   BLOCK:EVTS[PARSETREE] ≠ RNULL ∨ BLOCK:PROCS[PARSETREE] ≠ RNULL ∨
	   BLOCK:CMONS[PARSETREE] ≠ RNULL THEN BEGIN "make some variables"

	! Emit code to compute any array bounds expressions;
	C ← BLOCK:ARAYS[PARSETREE];
	WHILE C ≠ RNULL DO
	    BEGIN
	    F ← LLOP(C); ! Get array header;
	    FOR CNT ← 1 TIL ARRAYDEF:NUMDIMS[F] DO
		FOR T ← 0 TIL 1 DO
		    IF RECTYPE(ARRAYDEF:BOUNDS[F][CNT,T]) = LOC(EXPRN) THEN
			BEGIN
			MAKE_REMARK(PSDCODE,"Array bounds expression");
			EMITEXPR(ARRAYDEF:BOUNDS[F][CNT,T]);
			EMIT(PSDCODE,CHNGE_PSOP,PSINST);
			EMITOFFSET(PSDCODE,ARRAYDEF:BOUNDS[F][CNT,T+2])
			END
	    END;

	!  Declare variables;
	EMIT(PSDCODE,MVAR_PSOP,PSINST);  ! variable declaration;
	IF (T ← VAR_CNT(SVAL_DTYPE))≠0 THEN
	    BEGIN
	    MAKE_REMARK(PSDCODE,"Scalars");
	    EMIT(PSDCODE,SCLID,CONST);
	    EMIT(PSDCODE,T,CONST);
	    END;
	IF (T ← VAR_CNT(V3ECT_DTYPE))≠0 THEN
	    BEGIN
	    MAKE_REMARK(PSDCODE,"Vectors");
	    EMIT(PSDCODE,VCTID,CONST);
	    EMIT(PSDCODE,T,CONST);
	    END;
	IF (T←VAR_CNT(ROTN_DTYPE)+VAR_CNT(TRANS_DTYPE)+VAR_CNT(FRAME_DTYPE))≠0 THEN
	    BEGIN
	    MAKE_REMARK(PSDCODE,"Transes");
	    EMIT(PSDCODE,TRNID,CONST);
	    EMIT(PSDCODE,T,CONST);
	    END;

 	! Declare the arrays;
	C ← BLOCK:ARAYS[PARSETREE];
	IF C ≠ RNULL THEN MAKE_REMARK(PSDCODE,"Arrays");
	WHILE C ≠ RNULL DO
	    BEGIN
	    F ← LLOP(C); ! Get the array header;
	    MAKE_REMARK(PSDCODE,ARRAYDEF:NAME[F]);
	    ARRAYDEF:OFFSET[F] ← OFS;
	    EMITOFFSET(SYMFIL,F);
	    OFS ← OFS + 1;
	    T ← TYPE_GET(ARRAYDEF:DATATYPE[F]) + ARYID;
	    EMIT(PSDCODE,T,CONST); ! Emit the datatype;
	    EMIT(PSDCODE,ARRAYDEF:NUMDIMS[F],CONST);
	    FOR CNT ← 1 TIL ARRAYDEF:NUMDIMS[F] DO
		FOR T ← 1 STEP -1 UNTIL 0 DO
		    BEGIN
		    P ← ARRAYDEF:BOUNDS[F][CNT,T];
		    IF RECTYPE(P)=LOC(EXPRN) THEN P←ARRAYDEF:BOUNDS[F][CNT,T+2];
		    IF RECTYPE(P)=LOC(VARIABLE) THEN
			EMITOFFSET(PSDCODE,P)
		    ELSE
			BEGIN
			BITS ← SVAL:VAL[P]; ! Convert constant bound to integer;
			BITS ← BITS LOR '100000; ! Set sign bit for constants;
			EMIT(PSDCODE,BITS,CONST)
			END
		    END
	    END;

 	! Declare the events;
	C ← BLOCK:EVTS[PARSETREE];
	IF C ≠ RNULL THEN
	  BEGIN
	  MAKE_REMARK(PSDCODE,"Events");
	  CNT ← 0;
	  WHILE C ≠ RNULL DO
	    BEGIN  !  Count the events;
	    VARBL ← LLOP(C);
	    CNT ← CNT + 1;
	    VARIABLE:OFFSET[VARBL] ← OFS;
	    EMITOFFSET(SYMFIL,VARBL);
	    OFS ← OFS + 1;
	    END;
	  EMIT(PSDCODE,EVTID,CONST);
	  EMIT(PSDCODE,CNT,CONST);
	  END;

	! Declare each condition monitor;

	    DEFINE EV_CM    = 0;	! event;
	    DEFINE EXP_CM   = 1;	! expression or variable;
	    DEFINE DUR_CM   = 2;	! duration;
	    DEFINE FORCE_CM = 3;	! force sensing;
	    DEFINE HARDW_CM = 4;	! hardware monitoring;

	    ! Here's what the various types of condition monitors look like:

	    for all: (dec) LAB: "condition monitor checker"

	    for events: CMSKED, CMWAIT <offset>, CMTRIG
	    for variables & expressions: CMSKED, <time: 100>,
		<code for boolean condition>, JUMPC LAB, CMTRIG,
	    for durations: <code to get time to wait>, CMDUR,
	    for force sensing: {<<code to get force vect>,VMKFRC> or <code to get
		force frame>,  TMKFRC, <arm & coordinate bits>}
		<code to get force value>,CMFORCE,
	    for hardware monitoring: CMSENSE,

	    for everyone: <code for conclusion>,

	    for events and variables & expressions: JUMP (ref) LAB,
	    for the rest: CMDONE,

	In the cmon section of MVAR:

	    for everyone: <type>, (ref) LAB2, <environment size required>,

	    for force sensing and hardware monitoring: <bits>;

	C ← BLOCK:CMONS[PARSETREE];
	CNT ← 0;
	HERE ← LABELS ← NEW_RECORD (COLAB);
	WHILE C ≠ RNULL DO		! Assign an offset & label to each cmon;
	    BEGIN
	    MONITOR ← LLOP(C);
	    CNT ← CNT + 1;
	    CMON:OFFSET[MONITOR] ← OFS;
	    COLAB:LBEL[HERE] ← GENLABEL;
	    HERE ← COLAB:NEXT[HERE] ← NEW_RECORD(COLAB);
	    OFS ← OFS + 1;
	    END;

	C ← BLOCK:CMONS[PARSETREE];
	IF C ≠ RNULL THEN	! Declare the cmons;
	    BEGIN
	    MAKE_REMARK(PSDCODE,"Cmons");
	    EMIT(PSDCODE,CMNID,CONST);
	    EMIT(PSDCODE,CNT,CONST);
	    HERE ← LABELS;
	    WHILE C ≠ RNULL DO		! Info for CMMAK;
	      BEGIN "cmdcl"
	      MONITOR ← LLOP(C);
	      CTYPE ← IF (T←RECTYPE(CMON:CONDITION[MONITOR])) = LOC(VARIABLE) ∧
		VARIABLE:DATATYPE[CMON:CONDITION[MONITOR]] = EVENT_DTYPE THEN EV_CM
		  ELSE IF T=LOC(EXPRN) ∧ EXPRN:OP[CMON:CONDITION[MONITOR]]=AREF_OP
		    ∧ ARRAYDEF:DATATYPE[CELL:CAR[EXPRN:ARGS[CMON:CONDITION[MONITOR]]]]
		      = EVENT_DTYPE THEN EV_CM
		  ELSE IF T = LOC(VARIABLE) ∨ T = LOC(EXPRN) THEN EXP_CM
		  ELSE IF T = LOC(DURATION) THEN DUR_CM
		  ELSE IF T = LOC(FORCE) THEN FORCE_CM
		  ELSE HARDW_CM;
	      EMIT(PSDCODE,CTYPE,CONST);	! Tell what type of cmon it is;
	      EMIT(PSDCODE,COLAB:LBEL[HERE],SYMREF);	! Tell where the cmon starts;
	      HERE ← COLAB:NEXT[HERE];
	      T ← ENV_SIZE(CMON:CONCLUSION[MONITOR]);
	      EMIT(PSDCODE,T,CONST);	! How large an environment it will need;
	      IF CTYPE = FORCE_CM THEN	! What frcsig needs to know;
		BEGIN				! Figure out the bits;
		F ← CMON:CONDITION[MONITOR];
		BITS ← FORCE:REL[F] + (IF FORCE:DIRECT[F] = ZHAT THEN ZFORCE ELSE
			IF FORCE:DIRECT[F] = YHAT THEN YFORCE ELSE XFORCE);
		IF ¬FORCE:TYPE[F] THEN BITS ← BITS + XMOMENT;	! It's a torque;
		BITS ← BITS +
			(IF W_ARM_ON(CMON:FLAGS[MONITOR]) THEN YELARM ELSE BLUARM);
		IF CMON:FLAGS[MONITOR] LAND FSTOP THEN BITS ← BITS + FSTOP;
		EMIT(PSDCODE,BITS,CONST);
		END
	!     ELSE IF CTYPE = HARDW_CM THEN who knows what we need to do;
	      END "cmdcl";
	    END;

	! Declare the procedures;
	C ← BLOCK:PROCS[PARSETREE];
	CNT ← 0;
	WHILE C ≠ RNULL DO ! Assign an offset & a label to each procedure;
	    BEGIN
	    CNT ← CNT + 1;
	    F ← LLOP(C);
	    PROCDEF:OFFSET[F] ← OFS;
	    PROCDEF:LAB[F] ← GENLABEL;
	    OFS ← OFS + 1
	    END;

	C ← BLOCK:PROCS[PARSETREE];
	IF C ≠ RNULL THEN
	    BEGIN
	    MAKE_REMARK(PSDCODE,"Procedures");
	    EMIT(PSDCODE,PROID,CONST);
	    EMIT(PSDCODE,CNT,CONST);
	    END;

	WHILE C ≠ RNULL DO ! Emit the procedure header info;
	    BEGIN
	    F ← LLOP(C);
	    MAKE_REMARK(PSDCODE,PROCDEF:NAME[F]);
	    EMIT(PSDCODE,PROCDEF:NUMARGS[F],CONST);
	    EMIT(PSDCODE,PROCDEF:LAB[F],SYMREF); ! Start of procedure's body;
	    T ← ENV_SIZE(PROCDEF:BODY[F]);
	    EMIT(PSDCODE,T,CONST);
	    F ← PROCDEF:ARGS[F];
	    WHILE F ≠ RNULL DO
		BEGIN
		P ← LLOP(F);
		IF RECTYPE(P) = LOC(VARIABLE) THEN
		    T ← TYPE_GET(VARIABLE:DATATYPE[P]) +
! May want to change this if VALUE becomes the default;
			(IF VALARG_ON(VARIABLE:ATTRIBUTES[P]) THEN 0 ELSE REFID)
		ELSE T ← TYPE_GET(ARRAYDEF:DATATYPE[P]) + ARYID + REFID;
		EMIT(PSDCODE,T,CONST)
		END
	    END;

	EMIT(PSDCODE,0,CONST);		! End MVAR with a zero;
!  TSCAN:  BLOCK continued;

	C ← BLOCK:CMONS[PARSETREE];	! Emit code for each cmon;
	IF C ≠ RNULL THEN
	  BEGIN "cmmak"
	  LAB1 ← GENLABEL;
	  EMIT(PSDCODE,JUMP_PSOP,PSINST); ! Jump past cmon bodies;
	  EMIT(PSDCODE,LAB1,SYMREF);
	  MAKE_REMARK(PSDCODE,"Condition monitors");
	  COFS ← OFS;
	  HERE ← LABELS;
	  WHILE C ≠ RNULL DO
	    BEGIN "blkcmon"

	    MONITOR ← LLOP(C);
	    OFS ← (COFS LAND '17400) + '400;! Move to next lexical level, offset 0;

	    CTYPE ← IF (T←RECTYPE(CMON:CONDITION[MONITOR])) = LOC(VARIABLE) ∧
		VARIABLE:DATATYPE[CMON:CONDITION[MONITOR]] = EVENT_DTYPE THEN EV_CM
	      ELSE IF T=LOC(EXPRN) ∧ EXPRN:OP[CMON:CONDITION[MONITOR]]=AREF_OP
		∧ ARRAYDEF:DATATYPE[CELL:CAR[EXPRN:ARGS[CMON:CONDITION[MONITOR]]]]
		  = EVENT_DTYPE THEN EV_CM
	      ELSE IF T = LOC(VARIABLE) ∨ T = LOC(EXPRN) THEN EXP_CM
	      ELSE IF T = LOC(DURATION) THEN DUR_CM
	      ELSE IF T = LOC(FORCE) THEN FORCE_CM
	      ELSE HARDW_CM;

	    MAKE_REMARK(PSDCODE,"Condition monitor checker");
	    EMIT(PSDCODE,COLAB:LBEL[HERE],SYMDEC);	! Cmon start address;
	    CASE CTYPE OF BEGIN "c-m checker"

[EV_CM]	    BEGIN "cmevt"	!  An event to wait for;
		EMIT(PSDCODE,CMSKED_PSOP,PSINST);
		MAKE_REMARK(PSDCODE,"Event cmon");
		IF RECTYPE(CMON:CONDITION[MONITOR]) = LOC(EXPRN) THEN
		    BEGIN
		    MAKE_REMARK(PSDCODE,"Subscripts for event var");
		    EMITSUBS(CELL:CDR[EXPRN:ARGS[CMON:CONDITION[MONITOR]]])
		    END;
		EMIT(PSDCODE,CMWAIT_PSOP,PSINST);
		EMITOFFSET(PSDCODE,CMON:CONDITION[MONITOR]);
		EMIT(PSDCODE,CMTRIG_PSOP,PSINST);
	    END "cmevt";

[EXP_CM]    BEGIN  "cmexpr"	! An expression to be evaluated;
		EMIT(PSDCODE,CMSKED_PSOP,PSINST);
		EMIT(PSDCODE,100,CONST);  !  Waiting interval;
		EMITBOOL(CMON:CONDITION[MONITOR],0,COLAB:LBEL[HERE]);
		EMIT(PSDCODE,CMTRIG_PSOP,PSINST);
	    END "cmexpr";

[DUR_CM]    BEGIN "cmdur"	! A duration to wait for;
		EMITEXPR(DURATION:TIME[CMON:CONDITION[MONITOR]]); ! Get the time;
		EMIT(PSDCODE,CMDUR_PSOP,PSINST);
	    END "cmdur";

[FORCE_CM]  BEGIN "cmforce"	! A force to wait for;
		F ← CMON:CONDITION[MONITOR];
		IF FORCE:DIRECT[F] ≠ XHAT ∧ FORCE:DIRECT[F] ≠ YHAT
						∧ FORCE:DIRECT[F]≠ZHAT THEN
		    BEGIN				! Need to make force frame;
		    EMITEXPR(FORCE:DIRECT[F]);		! Get force vector;
		    EMIT(PSDCODE,VMKFRC_PSOP,PSINST);	! Make up force frame;
		    EMIT(PSDCODE,TFRCST_PSOP,PSINST);	! Set it up;
		    DUMY ← FTABLE +
			 (IF W_ARM_ON(CMON:FLAGS[MONITOR]) THEN YELARM ELSE BLUARM);
		    EMIT(PSDCODE,DUMY,CONST);	! Bits for SETC;
		    END

		ELSE IF FORCE:F_F[F] ≠ RNULL THEN
		    BEGIN				! Need to set up force frame;
		    EMITEXPR(F_FRAME:FRAME[FORCE:F_F[F]]); ! Get force frame;
		    EMIT(PSDCODE,TFRCST_PSOP,PSINST);	! Set it up;
		    EMIT(PSDCODE,F_FRAME:C_SYS[FORCE:F_F[F]],CONST); ! Bits for SETC;
		    END;

		EMITEXPR(FORCE:VAL[CMON:CONDITION[MONITOR]]);	 ! Get force value;
		EMIT(PSDCODE,CMFORCE_PSOP,PSINST);
	    END "cmforce";

[HARDW_CM]  EMIT(PSDCODE,CMSENSE_PSOP,PSINST)

	    END "c-m checker";

	    TSCAN(CMON:CONCLUSION[MONITOR]);

	    IF CTYPE = EV_CM ∨ CTYPE = EXP_CM THEN
		BEGIN
		EMIT(PSDCODE,JUMP_PSOP,PSINST);
		EMIT(PSDCODE,COLAB:LBEL[HERE],SYMREF); ! Cmon start address;
		END
	    ELSE EMIT(PSDCODE,CMDONE_PSOP,PSINST);

	    HERE ← COLAB:NEXT[HERE];
	    END "blkcmon";
	  EMIT(PSDCODE,LAB1,SYMDEC);	! So we can jump past the code for cmons;
	  OFS ← COFS;		! Restore lexical level;
	  END "cmmak";

	! Make the procedure bodies local to this block;
	C ← BLOCK:PROCS[PARSETREE];
	IF C ≠ RNULL THEN
	  BEGIN "proc make"
	  LAB1 ← GENLABEL;
	  EMIT(PSDCODE,JUMP_PSOP,PSINST); ! Jump past procedure bodies;
	  EMIT(PSDCODE,LAB1,SYMREF);
	  MAKE_REMARK(PSDCODE,"Procedures bodies");
	  COFS ← OFS;
	  WHILE C ≠ RNULL DO
	    BEGIN
	    F ← LLOP(C); ! Get procedure header;
	    OFS ← (COFS LAND '17400) + '400;! Move to next lexical level, offset 0;
	    EMIT(PSDCODE,PROCDEF:LAB[F],SYMDEC);
	    MAKE_REMARK(PSDCODE,PROCDEF:NAME[F]);
	    P ← PROCDEF:ARGS[F];
	    WHILE P ≠ RNULL DO
		BEGIN ! Assign offsets to procedure arguments;
		VARIABLE:OFFSET[CELL:CAR[P]] ← OFS;
		OFS ← OFS + 1;
		EMITOFFSET(SYMFIL,LLOP(P)) ! Who knows what ALAID will do with them;
		END;
	    P ← BLOCK:CODE[STMNT:SEMANTICS[PROCDEF:BODY[F]]];
	    WHILE P ≠ RNULL DO ! Generate code for the stmnts in the procedure;
		TSCAN(LLOP(P));
	    CASE PROCDEF:DATATYPE[F] OF
		BEGIN ! Make sure typed procedures return something;
[0]		; ! Not typed so don't bother putting anything on the stack;
[SVAL_DTYPE]	EMITEXPR(FALSEV);
[V3ECT_DTYPE]	EMITEXPR(NILVECT);
  ELSE		EMITEXPR(NILTRANS)
		END;
	    EMIT(PSDCODE,RETURN_PSOP,PSINST);
	    IF PROCDEF:DATATYPE[F]=0 THEN EMIT(PSDCODE,0,CONST)
				     ELSE EMIT(PSDCODE,-1,CONST);
	    END;
	  EMIT(PSDCODE,LAB1,SYMDEC);
	  OFS ← COFS	! Restore lexical level;
	  END "proc make"

	END "make some variables";

	!  Generate the code for the statements in the block;
	C ← BLOCK:CODE[PARSETREE];
	WHILE C ≠ RNULL DO
	    TSCAN(LLOP(C));

	IF (T ← (OFS - SAVOFS) LAND '377) THEN
	  BEGIN
	  MAKE_REMARK(PSDCODE,"Block end cleanup");
	  EMIT(PSDCODE,KVAR_PSOP,PSINST);	! Kill all the variables we made;
	  EMIT(PSDCODE,T,CONST);
	  OFS ← SAVOFS;			! Restore the offset to original state;
	  END;

	MAKE_REMARK(PSDCODE,"End of BLOCK");

	END "block"
!  TSCAN:  COBLOCK;

    ELSE IF STYP = LOC(COBLOCK) THEN
	BEGIN "coblock"
	RCLASS COLAB (INTEGER LBEL; RPTR(COLAB) NEXT);
	RPTR (COLAB) LABELS, HERE;
	INTEGER SAVOFS;  !  Holds OFS for the duration;
	RCELL C;
	PRELOAD_WITH JUMP_PSOP, DUMMY, ! 1-2;
	    SPROUT_PSOP, DUMMY,  ! 3-4;
	    TERMINATE_PSOP, ! 5;
	    DUMMY;  ! 6;
	    INTEGER OWN ARRAY DATA[1:6];
	PRELOAD_WITH PSINST, SYMREF, ! 1-2;
	    PSINST, SYMREF, ! 3-4;
	    PSINST,  ! 5;
	    SYMDEC;  ! 6;
	    INTEGER OWN ARRAY RELOC[1:6];
	HERE ← LABELS ← NEW_RECORD (COLAB);
	LAB1 ← DATA[2] ← GENLABEL;
	MAKE_REMARK(PSDCODE,"Coblock");
	EMIT(PSDCODE,DATA[1],RELOC[1],2); ! Jump to end label;

	SAVOFS ← OFS;
	OFS ← (OFS LAND '17400) + '400;  ! Move to next lexical level, offset 0;
	C ← COBLOCK:CODE[PARSETREE];
	WHILE C ≠ RNULL DO
	    BEGIN "onecob"
	    HERE ← COLAB:NEXT[HERE] ← NEW_RECORD(COLAB);
	    DATA[6] ← COLAB:LBEL[HERE] ← GENLABEL;
	    EMIT(PSDCODE,DATA[6],RELOC[6],1);  ! symdec;
	    MAKE_REMARK(PSDCODE,"  Costatement");
	    TSCAN(LLOP(C));
	    EMIT(PSDCODE,DATA[5],RELOC[5],1); ! Terminate;
	    END "onecob";
	OFS ← SAVOFS;  ! Back to previous level;
	DATA[6] ← LAB1;  ! Label for jump around cocode;
	EMIT(PSDCODE,DATA[6],RELOC[6],1);  ! symdec;
	HERE ← COLAB:NEXT[LABELS];
	C ← COBLOCK:CODE[PARSETREE];
	MAKE_REMARK(PSDCODE,"  epilog of Coblock");
	EMIT(PSDCODE,DATA[3],RELOC[3],1);  ! Sprout;
	WHILE HERE ≠ RNULL DO
	    BEGIN
	    DATA[4] ← COLAB:LBEL[HERE];
	    EMIT(PSDCODE,DATA[4],RELOC[4],1); !  Label of code;
	    LAB4 ← ENV_SIZE(LLOP(C));
	    EMIT(PSDCODE,LAB4,CONST); !  Environment size needed;
	    HERE ← COLAB:NEXT[HERE];
	    END;
	EMIT(PSDCODE,0,CONST,1);  !  Final zero;
	MAKE_REMARK(PSDCODE,"END COBLOCK");
	END "coblock"
!  TSCAN:  FORR, WHIL, UNTL, IFF, CASE, PAUSE, PROMPT, ABORT;

    ELSE IF STYP = LOC(FORR) THEN
	BEGIN "forr"
	! This is how it looks: [FOR LOOP] <stack initial, final, step>
	LAB1: {push subscripts for control variable, if any}
	XFORCHK <control variable> LAB2 <body> XFOREND LAB1 LAB2: [END FOR];

	MAKE_REMARK(PSDCODE,"FOR LOOP");
	EMITEXPR(FORR:INITIAL[PARSETREE]);
	    !  This will emit code for the calculation of the initial
	    value;
	EMITEXPR(FORR:FINAL[PARSETREE]);
	    !  This will emit code for the calculation of the final
	    value;
	EMITEXPR(FORR:STEP[PARSETREE]);
	    !  This will emit code for the calculation of the step
	    value;

	LAB1 ← GENLABEL;  ! Top of loop;
	LAB2 ← GENLABEL;  ! End of loop;
	EMIT(PSDCODE,LAB1,SYMDEC);

	IF RECTYPE(FORR:CONVAR[PARSETREE]) = LOC(EXPRN) THEN
	    BEGIN
	    RCELL C;
	    MAKE_REMARK(PSDCODE,"Array reference");
	    C ← EXPRN:ARGS[FORR:CONVAR[PARSETREE]];
	    EMITSUBS(CELL:CDR[C])
	    END;

	EMIT(PSDCODE,FORCHK_PSOP,PSINST);
	IF RECTYPE(FORR:CONVAR[PARSETREE]) = LOC(EXPRN) THEN
	    EMITOFFSET(PSDCODE,CELL:CAR[EXPRN:ARGS[FORR:CONVAR[PARSETREE]]])
	ELSE EMITOFFSET(PSDCODE,FORR:CONVAR[PARSETREE]);
	EMIT(PSDCODE,LAB2,SYMREF);

	TSCAN(FORR:BODY[PARSETREE]);

	EMIT(PSDCODE,FOREND_PSOP,PSINST);
	EMIT(PSDCODE,LAB1,SYMREF);
	EMIT(PSDCODE,LAB2,SYMDEC);

	MAKE_REMARK(PSDCODE,"END FOR");
	END "forr"

    ELSE IF STYP = LOC(WHIL) THEN
	BEGIN "while"
	MAKE_REMARK(PSDCODE,"WHILE Loop");
	LAB1 ← GENLABEL;  !  Loop head;
	LAB2 ← GENLABEL;  !  After end;
	EMIT(PSDCODE,LAB1,SYMDEC);  ! (dec) LAB1:   ;
	EMITBOOL(WHIL:COND[PARSETREE],0,LAB2);
	TSCAN(WHIL:BODY[PARSETREE]);
	 ! JUMP (ref) LAB1, (dec) LAB2:    ;
	EMIT(PSDCODE,JUMP_PSOP,PSINST);
	EMIT(PSDCODE,LAB1,SYMREF);
	EMIT(PSDCODE,LAB2,SYMDEC);
	MAKE_REMARK(PSDCODE,"END WHILE");
	END "while"

    ELSE IF STYP = LOC(UNTL) THEN
	BEGIN "until"
	MAKE_REMARK(PSDCODE,"DO UNTIL Loop");
	LAB1 ← GENLABEL;  !  Loop head;
	EMIT(PSDCODE,LAB1,SYMDEC);  ! (dec) LAB1:   ;
	TSCAN(UNTL:BODY[PARSETREE]); ! Loop body;
	EMITBOOL(UNTL:COND[PARSETREE],0,LAB1); ! Exit test;
	MAKE_REMARK(PSDCODE,"END DO UNTIL");
	END "until"

    ELSE IF STYP = LOC(IFF) THEN
	BEGIN "iff"
	MAKE_REMARK(PSDCODE,"IF");
	LAB1 ← GENLABEL;  ! The head of the ELSE part;
	LAB2 ← GENLABEL;  ! At the end of the IF;
	EMITBOOL(IFF:COND[PARSETREE],0,LAB1);
	MAKE_REMARK(PSDCODE,"THEN");
	TSCAN(IFF:THN[PARSETREE]);
	IF STMNT:SEMANTICS[IFF:ELS[PARSETREE]] ≠ NULL THEN
	    BEGIN
	    ! JUMP (ref) LAB2, (dec) LAB1:   ;
	    EMIT(PSDCODE,JUMP_PSOP,PSINST);
	    EMIT(PSDCODE,LAB2,SYMREF);
	    END;
	EMIT(PSDCODE,LAB1,SYMDEC);
	IF STMNT:SEMANTICS[IFF:ELS[PARSETREE]] ≠ NULL THEN
	    BEGIN
	    MAKE_REMARK(PSDCODE,"ELSE");
	    TSCAN(IFF:ELS[PARSETREE]);
	    EMIT(PSDCODE,LAB2,SYMDEC);  ! (dec)  LAB2:   ;
	    END;
	MAKE_REMARK(PSDCODE,"FI");
	END "iff"

    ELSE IF STYP = LOC(KASE) THEN
	BEGIN "case"
	RCELL C;
	INTEGER S,I,N;
	MAKE_REMARK(PSDCODE,"CASE");
	EMITEXPR(KASE:INDEX[PARSETREE]);  ! Get the case index on the stack;
	N ← KASE:RANGE[PARSETREE];
	S ← KASE:NSTMNTS[PARSETREE];
	EMIT(PSDCODE,CASE_PSOP,PSINST);
	EMIT(PSDCODE,N,CONST); ! Max index value (+1) or -max if ELSE given;
	FOR I ← 0 TIL S DO ! Assign labels to each statement;
	  KASE:LABS[PARSETREE][I,1] ← GENLABEL;
	LAB1 ← KASE:LABS[PARSETREE][S,1];
	IF N ≥ 0 THEN KASE:LABS[PARSETREE][N,1] ← LAB1 ELSE N ← ABS N;
		! So null statements jump to right place;
	FOR I ← 0 TIL N DO ! Make dispatch table;
	  EMIT(PSDCODE,KASE:LABS[PARSETREE][KASE:LABS[PARSETREE][I,0],1],SYMREF);
	C ← KASE:STMNTS[PARSETREE];
	FOR I ← 0 TIL S-1 DO ! Now emit the labelled statements;
	  BEGIN
	  EMIT(PSDCODE,KASE:LABS[PARSETREE][I,1],SYMDEC);
	  TSCAN(LLOP(C));
	  IF I ≠ S-1 THEN
	    BEGIN ! A slight optimization(?);
	    EMIT(PSDCODE,JUMP_PSOP,PSINST); ! Jump to next statement;
	    EMIT(PSDCODE,LAB1,SYMREF)
	    END
	  END;
	EMIT(PSDCODE,LAB1,SYMDEC)
	END "case"

    ELSE IF STYP = LOC(PAUSE) THEN
	BEGIN "pause"
	MAKE_REMARK(PSDCODE,"PAUSE");
	 ! Get the value on the stack;
	EMITEXPR(PAUSE:VAL[PARSETREE]);
	EMIT(PSDCODE,PAUSE_PSOP,PSINST);
	END "pause"

    ELSE IF STYP = LOC(PROMPT) THEN
	BEGIN "prompt"
	MAKE_REMARK(PSDCODE,"PROMPT");
	PRINT_LIST(PROMPT:VAL[PARSETREE]);	! Take care of any print items;
	EMIT(PSDCODE,PROMPT_PSOP,PSINST);
	END "prompt"

    ELSE IF STYP = LOC(ABORT) THEN
	BEGIN "abort"
	MAKE_REMARK(PSDCODE,"ABORT");
	EMIT(PSDCODE,ABORT_PSOP,PSINST);
	PRINT_LIST(ABORT:VAL[PARSETREE]); ! Take care of print items;
	MAKE_REMARK(PSDCODE,"DDT");	! Control passes to DDT;
	EMIT(PSDCODE,DDT_PSOP,PSINST);
	END "abort"

    ELSE GO TO MIDLABEL;
    GO TO ENDLABEL;  !	This is to avoid parse stack overflow;
!  TSCAN:  ASSIGNMENT, PRNT, CALL, RETURN;

    MIDLABEL:  !  Necessary to avoid parse stack overflow;
    IF STYP = LOC(ASSIGNMENT) THEN
	BEGIN "assignment"
	MAKE_REMARK(PSDCODE,"Assignment");
	!  Get the value on the stack;
	EMITEXPR(ASSIGNMENT:VAL[PARSETREE]);
	! Emit "change variable to value on stack";
	IF RECTYPE(ASSIGNMENT:VAR[PARSETREE]) = LOC(EXPRN) THEN
	    BEGIN
	    RCELL C;
	    MAKE_REMARK(PSDCODE,"Array reference");
	    C ← EXPRN:ARGS[ASSIGNMENT:VAR[PARSETREE]];
	    EMITSUBS(CELL:CDR[C]);
	    EMIT(PSDCODE,CHNGE_PSOP,PSINST);
	    EMITOFFSET(PSDCODE,CELL:CAR[C])
	    END
	ELSE
	    BEGIN
	    EMIT(PSDCODE,CHNGE_PSOP,PSINST);
	    EMITOFFSET(PSDCODE,ASSIGNMENT:VAR[PARSETREE])
	    END
	END "assignment"

    ELSE IF STYP = LOC(PRNT) THEN
	PRINT_LIST(PRNT:VAL[PARSETREE])		! Take care of print items;

    ELSE IF STYP = LOC(EXPRN) THEN
	BEGIN "procedure call"
	EMITCALL(PARSETREE);
	IF PROCDEF:DATATYPE[CELL:CAR[EXPRN:ARGS[PARSETREE]]] ≠ 0 THEN
	     EMIT(PSDCODE,POP_PSOP,PSINST) ! Flush value procedure returned;
	END

    ELSE IF STYP = LOC(RETRN) THEN
	BEGIN "procedure return"
	MAKE_REMARK(PSDCODE,"Return");
	IF RETRN:VAL[PARSETREE] ≠ RNULL THEN
	    EMITEXPR(RETRN:VAL[PARSETREE]);
	EMIT(PSDCODE,RETURN_PSOP,PSINST);
	IF RETRN:VAL[PARSETREE] ≠ RNULL THEN EMIT(PSDCODE,-1,CONST)
					ELSE EMIT(PSDCODE,0,CONST);
	END
!  TSCAN:  CMON, CMABLE;

    ELSE IF STYP = LOC(CMON) THEN
	BEGIN
	IF ¬DEFER_ON(CMON:FLAGS[PARSETREE]) THEN
	   BEGIN "cmon"
	   MAKE_REMARK(PSDCODE,"Enable condition monitor");
	   EMIT(PSDCODE,CMENBL_PSOP,PSINST);
	   EMIT(PSDCODE,CMON:OFFSET[PARSETREE],CONST);
	   END "cmon"
	END

    ELSE IF STYP = LOC(CMABLE) THEN
	BEGIN "cmable"
	RPTR(CMON,LBLVAR) CMONV;  ! The CMON;
	CMONV ← CMABLE:WHAT[PARSETREE];
	IF RECTYPE(CMONV) = LOC(LBLVAR)
	THEN CMONV ← LBLVAR:SEMANTICS[CMONV];
	IF CMABLE:FLAG[PARSETREE]
	THEN BEGIN  "disable"
	    MAKE_REMARK(PSDCODE,"Disable");
	    EMIT(PSDCODE,CMDSBL_PSOP,PSINST);  !  CMDSBL (offset);
	    EMIT(PSDCODE,CMON:OFFSET[CMONV],CONST);
	    END "disable"
	ELSE BEGIN  "enable"
	    MAKE_REMARK(PSDCODE,"Enable");
	    EMIT(PSDCODE,CMENBL_PSOP,PSINST);  !  CMENBL (offset);
	    EMIT(PSDCODE,CMON:OFFSET[CMONV],CONST);
	    END "enable"
	END "cmable"
!  TSCAN:  MOVE$, OPERATE, CENTER, RETRY, STOP, SETBASE, WRIST;

    ELSE IF STYP = LOC(MOVE$) THEN
	BEGIN "move"
	RPTR(DEXPR) DESTEXPR;  ! The destiniation expression;
	RPTR(APPROACH) ARR;	! Approach clause (if any);
	RCELL CLAUS; ! The list of clauses;
	INTEGER BITS;
	RANY X;
	RPTR(ERROR) EPTR;
	MAKE_REMARK(PSDCODE,"Move");

	!  Generate code for all deproaches & via points that are expressions;
	CLAUS ← MOVE$:CLAUSES[PARSETREE];
	WHILE CLAUS ≠ RNULL DO
	    BEGIN "mexpr"
	    RANY THISCLAUSE;
	    THISCLAUSE ← LLOP(CLAUS);
	    IF RECTYPE(THISCLAUSE) = LOC(ERROR) THEN EPTR ← THISCLAUSE;
	    IF RECTYPE(THISCLAUSE) = LOC(VIA) AND
	    RECTYPE(DEXPR:EXPN[VIA:ACTPLACE[THISCLAUSE]]) = LOC(EXPRN)
	    THEN BEGIN "via"
		EMITEXPR(DEXPR:EXPN[VIA:ACTPLACE[THISCLAUSE]]);
		EMIT(PSDCODE,CHNGE_PSOP,PSINST);
		EMITOFFSET(PSDCODE,DEXPR:VAR[VIA:ACTPLACE[THISCLAUSE]]);
		END "via";
	    IF RECTYPE(THISCLAUSE) = LOC(DEPARTURE) AND
	    RECTYPE(DEXPR:EXPN[DEPARTURE:ACTPLACE[THISCLAUSE]]) = LOC(EXPRN)
	    THEN BEGIN "dep"
		EMITEXPR(DEXPR:EXPN[DEPARTURE:ACTPLACE[THISCLAUSE]]);
		EMIT(PSDCODE,CHNGE_PSOP,PSINST);
		EMITOFFSET(PSDCODE,DEXPR:VAR[DEPARTURE:ACTPLACE[THISCLAUSE]]);
		END "dep";
	    IF RECTYPE(THISCLAUSE) = LOC(APPROACH)
	    THEN BEGIN "arr"
		ARR←THISCLAUSE;
		IF RECTYPE(DEXPR:EXPN[APPROACH:ACTPLACE[THISCLAUSE]])=LOC(EXPRN) THEN
		    BEGIN
		    EMITEXPR(DEXPR:EXPN[APPROACH:ACTPLACE[THISCLAUSE]]);
		    EMIT(PSDCODE,CHNGE_PSOP,PSINST);
		    EMITOFFSET(PSDCODE,DEXPR:VAR[APPROACH:ACTPLACE[THISCLAUSE]]);
		    END;
		END "arr";
	    END "mexpr";

	!  Generate code for the destination point, if it is an expression;
	DESTEXPR ← MOVE$:DEXP[PARSETREE];
	IF RECTYPE(DEXPR:EXPN[DESTEXPR]) = LOC(EXPRN)
	THEN BEGIN "movdest" ! Must emit code to evaluate the destination;
	    EMITEXPR(DEXPR:EXPN[DESTEXPR]);
	    EMIT(PSDCODE,CHNGE_PSOP,PSINST);
	    EMITOFFSET(PSDCODE,DEXPR:VAR[DESTEXPR]);
	    END "movdest";

	LAB1 ← GENLABEL;  ! Start of Move;
	EMIT(PSDCODE,LAB1,SYMDEC);	! RETRY will re-do from here on;

	LAB2 ← GENLABEL;  ! End of Move;
	LAB4 ← RETRY_LAB;
	RETRY_LAB ← LAB1;  ! Save old retry label & set up one for this move;

	! Set up force frame (if any);
	CLAUS ← MOVE$:CLAUSES[PARSETREE];
	WHILE CLAUS ≠ RNULL DO
	    BEGIN
	    X ← LLOP(CLAUS);
	    IF RECTYPE(X) = LOC(F_FRAME) THEN
		BEGIN "f_frame"
		EMITEXPR(F_FRAME:FRAME[X]);		! Get force frame;
		EMIT(PSDCODE,TFRCST_PSOP,PSINST);	! Set it up;
		BITS ← F_FRAME:C_SYS[X] lor
		 MEMLOC(IF MOVE$:CF[PARSETREE]=YARM THEN YELARM ELSE BLUARM,INTEGER);
		EMIT(PSDCODE,BITS,CONST);		! Bits for arm & co_ord sys;
							! (hand or table);
		DONE;
		END "f_frame";
	    END;

	! Set up all forces being applied in this MOVE;
	CLAUS ← MOVE$:CLAUSES[PARSETREE];
	WHILE CLAUS ≠ RNULL DO
	    BEGIN
	    X ← LLOP(CLAUS);
	    IF RECTYPE(X) = LOC(FORCE) THEN
		BEGIN "force"
		! First set up the control bits for COMPLY;
		IF FORCE:DIRECT[X] = XHAT THEN BITS ← XFORCE
		ELSE IF FORCE:DIRECT[X] = YHAT THEN BITS ← YFORCE
		ELSE IF FORCE:DIRECT[X] = ZHAT THEN BITS ← ZFORCE
		ELSE BEGIN "make force frame"
		    BITS ← XFORCE;
		    EMITEXPR(FORCE:DIRECT[X]);		! Get force vector;
		    EMIT(PSDCODE,VMKFRC_PSOP,PSINST);	! Make force frame;
		    EMIT(PSDCODE,TFRCST_PSOP,PSINST);	! Set it up;
		    EMIT(PSDCODE,F_FRAME:C_SYS[FORCE:F_F[X]],CONST); ! Bits for SETC;
		    END "make force frame";
		IF ¬FORCE:TYPE[X] THEN BITS ← BITS + XMOMENT;	! It's a torque;
		BITS ← BITS + (IF MOVE$:CF[PARSETREE]=YARM THEN YELARM ELSE BLUARM);
		EMITEXPR(FORCE:VAL[X]);			! Get the force's magnitude;
		EMIT(PSDCODE,COMPLY_PSOP,PSINST);
		EMIT(PSDCODE,BITS,CONST);		! Bits for COMPLY;
		END "force";
	    END;

	! See if we should zero the force wrist;
	CLAUS ← MOVE$:CLAUSES[PARSETREE];
	WHILE CLAUS ≠ RNULL ∧ RECTYPE(CELL:CAR[CLAUS]) ≠ LOC(SETBASE)
	    DO LLOP(CLAUS);	! Find the setbase clause if it's present;
	IF CLAUS ≠ RNULL ∧ SETBASE:VAL[CELL:CAR[CLAUS]] THEN
	    BEGIN "setbase"
	    MAKE_REMARK(PSDCODE,"Setbase");
	    EMIT(PSDCODE,SETBASE_PSOP,PSINST);
	    END "setbase";

	! Set up stiffness/compliance for this MOVE;
	CLAUS ← MOVE$:CLAUSES[PARSETREE];
	WHILE CLAUS ≠ RNULL ∧ RECTYPE(CELL:CAR[CLAUS]) ≠ LOC(STIFF)
	    DO LLOP(CLAUS);	! Find the stiffness clause if it's present;
	IF CLAUS ≠ RNULL THEN 	! Got one;
	    BEGIN "stiff"
	    X←LLOP(CLAUS);
	    MAKE_REMARK(PSDCODE,"Set Stiff");
	    EMITEXPR(F_FRAME:FRAME[STIFF:F_F[X]]);  ! Push compliance frame;
	    EMITEXPR(STIFF:G[X]);	! Push stiffness values - torque first;
	    EMITEXPR(STIFF:K[X]);	!  then force;
	    EMIT(PSDCODE,STIFF_PSOP,PSINST);
	    BITS ← F_FRAME:C_SYS[STIFF:F_F[X]] lor
	     MEMLOC(IF MOVE$:CF[PARSETREE]=YARM THEN YELARM ELSE BLUARM,INTEGER);
	    EMIT(PSDCODE,BITS,CONST);	! Bits for arm & co_ord sys (hand or table);
	    END "stiff";

	! See if any force gathering to set up for this MOVE;
	CLAUS ← MOVE$:CLAUSES[PARSETREE];
	WHILE CLAUS ≠ RNULL ∧ RECTYPE(CELL:CAR[CLAUS]) ≠ LOC(GATHER)
	    DO LLOP(CLAUS);	! Find the gather clause if it's present;
	IF CLAUS ≠ RNULL THEN 	! Got it;
	    BEGIN "gather"
	    X←LLOP(CLAUS);
	    MAKE_REMARK(PSDCODE,"Set up Gathering");
	    EMIT(PSDCODE,GATHR_PSOP,PSINST);
	    EMIT(PSDCODE,GATHER:BITS[X],CONST);	! Tell which forces to gather;
	    END "gather";

	! Enable any condition monitors local to this move statement;
	CLAUS ← MOVE$:CLAUSES[PARSETREE];
	WHILE CLAUS ≠ RNULL DO
	    BEGIN
	    X←LLOP(CLAUS);
	    IF RECTYPE(X)=LOC(VIA) THEN X ← VIA:CODE[X];
	    IF RECTYPE(X)=LOC(DEPARTURE) THEN X ← DEPARTURE:CODE[X];
	    IF RECTYPE(X)=LOC(APPROACH) THEN X ← APPROACH:CODE[X];
	    IF RECTYPE(X)=LOC(CMON) ∧ ¬DEFER_ON(CMON:FLAGS[X]) THEN
		BEGIN "cmon"
		MAKE_REMARK(PSDCODE,"Enable condition monitor");
		EMIT(PSDCODE,CMENBL_PSOP,PSINST);
		EMIT(PSDCODE,CMON:OFFSET[X],CONST);
		END "cmon"
	    END;

	TRJCLC(PARSETREE);

	BITS ← IF EPTR ≠ RNULL THEN SVAL:VAL[ERROR:BITS[EPTR]] ELSE 0;
	EMIT(PSDCODE,BITS,CONST);	! error bit mask;
	EMIT(PSDCODE,LAB2,SYMREF);	! end of MOVE;
	EMIT(PSDCODE,LAB1,SYMREF);	! RETRY address;

	IF EPTR ≠ RNULL THEN
	    BEGIN
	    MAKE_REMARK(PSDCODE,"Error handler");
	    TSCAN(ERROR:BODY[EPTR]);	! Generate code for error handler;
	    END;

	RETRY_LAB ← LAB4;		! Restore old retry label;

	! Disable any condition monitors local to this move statement;
	EMIT(PSDCODE,LAB2,SYMDEC);	! Come here if no error handler;
	CLAUS ← MOVE$:CLAUSES[PARSETREE];
	WHILE CLAUS ≠ RNULL DO
	    BEGIN
	    X←LLOP(CLAUS);
	    IF RECTYPE(X)=LOC(VIA) THEN X ← VIA:CODE[X];
	    IF RECTYPE(X)=LOC(DEPARTURE) THEN X ← DEPARTURE:CODE[X];
	    IF RECTYPE(X)=LOC(APPROACH) THEN X ← APPROACH:CODE[X];
	    IF RECTYPE(X)=LOC(CMON) THEN
		BEGIN "cmon"
		MAKE_REMARK(PSDCODE,"Disable condition monitor");
		EMIT(PSDCODE,CMDSBL_PSOP,PSINST);
		EMIT(PSDCODE,CMON:OFFSET[X],CONST);
		END "cmon"
	    END;

	! Update deproach variable if need be;
	IF ARR≠RNULL THEN
	    BEGIN
	    IF APPROACH:THRU[ARR]=NILDEPROACH THEN EMITEXPR(NILDEPROACH)
		ELSE EMITEXPR(DEXPR:VAR[APPROACH:ACTPLACE[ARR]]);
	    EMIT(PSDCODE,CHNGE_PSOP,PSINST);
	    IF MOVE$:CF[PARSETREE]=BARM THEN  EMITOFFSET(PSDCODE,BDEPROACH)
					ELSE EMITOFFSET(PSDCODE,YDEPROACH);
	    END;
	END "move"

    ELSE IF STYP = LOC(OPERATE) THEN
	BEGIN "operate"
	RANY TIME_PTR, TORQUE_PTR, VELOCITY_PTR, SW_TIME_PTR, EPTR;
	RANY X;
	RCELL CLAUS; ! The list of clauses;
	INTEGER DEV,BITS,MECH;

	MAKE_REMARK(PSDCODE,"Operate");
	LAB1 ← GENLABEL;  ! Start of operate;
	EMIT(PSDCODE,LAB1,SYMDEC);

	LAB2 ← GENLABEL;  ! End of Operate;
	LAB4 ← RETRY_LAB;
	RETRY_LAB ← LAB1;  ! Save old retry label & set up one for this move;

	IF OPERATE:WHAT[PARSETREE] ≠ VISE AND
	   OPERATE:WHAT[PARSETREE] ≠ DRIVER
	THEN COMERR("Can't OPERATE anything but the vise or driver yet");

	! Find any clauses for this operate statement;
	CLAUS ← OPERATE:CLAUSES[PARSETREE];
	WHILE CLAUS ≠ RNULL DO
	    BEGIN
	    X←LLOP(CLAUS);
	    IF RECTYPE(X)=LOC(ERROR) THEN EPTR ← X ELSE
	    IF RECTYPE(X)=LOC(DURATION) THEN TIME_PTR ← X ELSE
	    IF RECTYPE(X)=LOC(FORCE) THEN TORQUE_PTR ← X ELSE
	    IF RECTYPE(X)=LOC(VELOCITY) THEN VELOCITY_PTR ← X ELSE
	    IF RECTYPE(X)=LOC(SW_TIME) THEN SW_TIME_PTR ← X;
	    END;

	IF OPERATE:WHAT[PARSETREE] = VISE THEN
	  BEGIN		! push vise values;
	   DEV ← 2;
	   MECH ← '20;
	   IF RECTYPE(OPERATE:DEST[PARSETREE])=LOC(CHAR_REC) THEN
	      BEGIN ! open/close til touch;
	       BITS ← 1;       ! Set no_nulling bit;
	       EMITEXPR(IF CHAR_REC:CHAR[OPERATE:DEST[PARSETREE]]="-" THEN FALSEV
				ELSE NEW_SVAL(MAX_VISE_OPENING));
	      END
	    ELSE EMITEXPR(OPERATE:DEST[PARSETREE]);
	   IF bits = 0 THEN EMITEXPR(FALSEV)	! No stop wait time if width specified;
	    ELSE EMITEXPR(IF SW_TIME_PTR=RNULL THEN NEW_SVAL(0.25)  ! ???***???;
				   ELSE SW_TIME:VAL[SW_TIME_PTR]);
	   EMITEXPR(IF TIME_PTR=RNULL THEN NEW_SVAL(8.00)  ! *** should be enough;
			     ELSE DURATION:TIME[TIME_PTR]);
	   END	! push vise values;
	  ELSE
	   BEGIN ! push driver values;
	   DEV ← 1;
	   MECH ← '40;
	   BITS ← 0;
	  ! velocity value will be ignored if torque value is specified;
	   EMITEXPR(IF VELOCITY_PTR=RNULL THEN NEW_SVAL(60.0)
			     ELSE VELOCITY:VELOC[VELOCITY_PTR]);
	   EMITEXPR(IF TORQUE_PTR=RNULL THEN FALSEV
			     ELSE FORCE:VAL[TORQUE_PTR]);
	   EMITEXPR(IF TIME_PTR=RNULL THEN NEW_SVAL(5.00)  ! *** enough??? ***;
			     ELSE DURATION:TIME[TIME_PTR]);
	   END;

	! Enable any condition monitors local to this operate statement;
	CLAUS ← OPERATE:CLAUSES[PARSETREE];
	WHILE CLAUS ≠ RNULL DO
	    BEGIN
	    X←LLOP(CLAUS);
	    IF RECTYPE(X)=LOC(CMON) ∧ ¬DEFER_ON(CMON:FLAGS[X]) THEN
		BEGIN "cmon"
		MAKE_REMARK(PSDCODE,"Enable condition monitor");
		EMIT(PSDCODE,CMENBL_PSOP,PSINST);
		EMIT(PSDCODE,CMON:OFFSET[X],CONST);
		END "cmon"
	    END;

	EMIT(PSDCODE,OPERATE_PSOP,PSINST);
	EMIT(PSDCODE,DEV,CONST);	! which device - servo bits;
	EMIT(PSDCODE,BITS,CONST);	! command bits - for vise;
	EMIT(PSDCODE,MECH,CONST);	! mechanism bits;

	BITS ← IF EPTR ≠ RNULL THEN SVAL:VAL[ERROR:BITS[EPTR]] ELSE 0;
	EMIT(PSDCODE,BITS,CONST);	! error bit mask;
	EMIT(PSDCODE,LAB2,SYMREF);	! end of OPERATE;
	EMIT(PSDCODE,LAB1,SYMREF);	! error address;

	IF EPTR ≠ RNULL THEN
	    BEGIN
	    MAKE_REMARK(PSDCODE,"Error handler");
	    TSCAN(ERROR:BODY[EPTR]);	! Generate code for error handler;
	    END;

	RETRY_LAB ← LAB4;		! Restore old retry label;

	! Disable any condition monitors local to this operate statement;
	EMIT(PSDCODE,LAB2,SYMDEC);	! Come here if no error handler;
	CLAUS ← OPERATE:CLAUSES[PARSETREE];
	WHILE CLAUS ≠ RNULL DO
	    BEGIN
	    X←LLOP(CLAUS);
	    IF RECTYPE(X)=LOC(CMON) THEN
		BEGIN "cmon"
		MAKE_REMARK(PSDCODE,"Disable condition monitor");
		EMIT(PSDCODE,CMDSBL_PSOP,PSINST);
		EMIT(PSDCODE,CMON:OFFSET[X],CONST);
		END "cmon"
	    END;

	END "operate"

    ELSE IF STYP = LOC(CENTER) THEN
	BEGIN "center"
	RPTR(ERROR) EPTR;
	RANY X,CLAUS;
	INTEGER BITS;

	MAKE_REMARK(PSDCODE,"Center");
	LAB1 ← GENLABEL;  ! Start of Center;
	EMIT(PSDCODE,LAB1,SYMDEC);	! RETRY will re-do from here on;

	LAB2 ← GENLABEL;  ! End of Center;
	LAB4 ← RETRY_LAB;
	RETRY_LAB ← LAB1;  ! Save old retry label & set up one for this move;

	! Find any clauses for this center statement;
	CLAUS ← CENTER:CLAUSES[PARSETREE];
	WHILE CLAUS ≠ RNULL DO
	    BEGIN
	    X←LLOP(CLAUS);
	    IF RECTYPE(X)=LOC(ERROR) THEN EPTR ← X;
	    END;

	CENTCLC(PARSETREE);

	BITS ← IF EPTR ≠ RNULL THEN SVAL:VAL[ERROR:BITS[EPTR]] ELSE 0;
	EMIT(PSDCODE,BITS,CONST);	! error bit mask;
	EMIT(PSDCODE,LAB2,SYMREF);	! end of CENTER;
	EMIT(PSDCODE,LAB1,SYMREF);	! error address;

	IF EPTR ≠ RNULL THEN
	    BEGIN
	    MAKE_REMARK(PSDCODE,"Error handler");
	    TSCAN(ERROR:BODY[EPTR]);	! Generate code for error handler;
	    END;

	RETRY_LAB ← LAB4;		! Restore old retry label;

	EMIT(PSDCODE,LAB2,SYMDEC);	! Come here if no error handler;
	END "center"

    ELSE IF STYP = LOC(RETRY) THEN
	BEGIN "retry"
	MAKE_REMARK(PSDCODE,"Retry");
	IF RETRY_LAB ≠ 0 THEN
	    BEGIN
	    EMIT(PSDCODE,JUMP_PSOP,PSINST);
	    EMIT(PSDCODE,RETRY_LAB,SYMREF); ! retry address;
	    END
	ELSE COMERR("RETRY not inside error handler. Will ignore it.");
	END "retry"

    ELSE IF STYP = LOC(STOP) THEN
	BEGIN "stop"
	MAKE_REMARK(PSDCODE,"Stop");
	STOPCLC(PARSETREE);
	END "stop"

    ELSE IF STYP = LOC(SETBASE) THEN
	BEGIN "setbase"
	MAKE_REMARK(PSDCODE,"Setbase");
	EMIT(PSDCODE,SETBASE_PSOP,PSINST);
	END "setbase"

    ELSE IF STYP = LOC(WRIST) THEN
	BEGIN "wrist"
	MAKE_REMARK(PSDCODE,"wrist");
	EMIT(PSDCODE,WRIST_PSOP,PSINST);
	EMITOFFSET(PSDCODE,WRIST:K[PARSETREE]);
	EMITOFFSET(PSDCODE,WRIST:G[PARSETREE]);
	END "wrist"

!  TSCAN:  COMMENT, AFFIX, UNFIX;

    ELSE IF STYP = LOC(COMMNT) THEN
	BEGIN "commnt"
	END "commnt"

    ELSE IF STYP = LOC(AFFIX) THEN
	BEGIN "affix"
	INTEGER BITS;
	MAKE_REMARK(PSDCODE,"Affixment");
	IF AFFIX:ATEXP[PARSETREE] ≠ RNULL THEN
	    BEGIN 	! Explicitly given AT expression;
	    EMITEXPR(AFFIX:ATEXP[PARSETREE]);
	    BITS ← 0;
	    END
	  ELSE BITS ← '100000;	! Indicate the trans should be computed by runtime;
	IF RECTYPE(AFFIX:BYVAR[PARSETREE]) = LOC(EXPRN) THEN
	    BEGIN
	    MAKE_REMARK(PSDCODE,"Subscripts for byvar");
	    EMITSUBS(CELL:CDR[EXPRN:ARGS[AFFIX:BYVAR[PARSETREE]]])
	    END;
	IF RECTYPE(AFFIX:FRAME2[PARSETREE]) = LOC(EXPRN) THEN
	    BEGIN
	    MAKE_REMARK(PSDCODE,"Subscripts for frame2");
	    EMITSUBS(CELL:CDR[EXPRN:ARGS[AFFIX:FRAME2[PARSETREE]]])
	    END;
	IF RECTYPE(AFFIX:FRAME1[PARSETREE]) = LOC(EXPRN) THEN
	    BEGIN
	    MAKE_REMARK(PSDCODE,"Subscripts for frame1");
	    EMITSUBS(CELL:CDR[EXPRN:ARGS[AFFIX:FRAME1[PARSETREE]]])
	    END;
	IF ¬AFFIX:RIGID[PARSETREE] THEN BITS ← BITS + '400;	! Non-rigid;
	IF RECTYPE(AFFIX:BYVAR[PARSETREE]) = LOC(EXPRN) ∨
	    VARIABLE:NAME[AFFIX:BYVAR[PARSETREE]] ≠ NULL THEN LAB1 ← TRUE
	  ELSE LAB1 ← FALSE;  ! if ALC generated;
	IF LAB1 THEN BITS ← BITS + '2000; ! Explicitly named trans;
	EMIT(PSDCODE,AFFIX_PSOP,PSINST);
	EMITOFFSET(PSDCODE,AFFIX:FRAME1[PARSETREE]);
	EMITOFFSET(PSDCODE,AFFIX:FRAME2[PARSETREE]);
	EMIT(PSDCODE,BITS,CONST);	! Tell what type of affixment to make;
	IF LAB1 THEN EMITOFFSET(PSDCODE,AFFIX:BYVAR[PARSETREE]);
	MAKE_REMARK(PSDCODE,"End of affixment");
	END "affix"

    ELSE IF STYP = LOC(UNFIX) THEN
	BEGIN "unfix"
	MAKE_REMARK(PSDCODE,"Unfixment");
	IF RECTYPE(UNFIX:FRAME2[PARSETREE]) = LOC(EXPRN) THEN
	    BEGIN
	    MAKE_REMARK(PSDCODE,"Subscripts for frame2");
	    EMITSUBS(CELL:CDR[EXPRN:ARGS[UNFIX:FRAME2[PARSETREE]]])
	    END;
	IF RECTYPE(UNFIX:FRAME1[PARSETREE]) = LOC(EXPRN) THEN
	    BEGIN
	    MAKE_REMARK(PSDCODE,"Subscripts for frame1");
	    EMITSUBS(CELL:CDR[EXPRN:ARGS[UNFIX:FRAME1[PARSETREE]]])
	    END;
	EMIT(PSDCODE,UNFIX_PSOP,PSINST);
	EMITOFFSET(PSDCODE,UNFIX:FRAME1[PARSETREE]);
	EMITOFFSET(PSDCODE,UNFIX:FRAME2[PARSETREE]);
	END "unfix"
!  TSCAN:  EVDO;

    ELSE IF STYP = LOC(EVDO) THEN
	BEGIN "evdo"
	MAKE_REMARK(PSDCODE,"Event operation");
	IF RECTYPE(EVDO:VAR[PARSETREE]) = LOC(EXPRN) THEN
	    BEGIN
	    MAKE_REMARK(PSDCODE,"Subscripts for event var");
	    EMITSUBS(CELL:CDR[EXPRN:ARGS[EVDO:VAR[PARSETREE]]]);
	    END;
	IF EVDO:OP[PARSETREE] = 0
	THEN EMIT(PSDCODE,SIGNAL_PSOP,PSINST)
	ELSE EMIT(PSDCODE,WAITE_PSOP,PSINST);
	EMITOFFSET(PSDCODE,EVDO:VAR[PARSETREE]);
	END "evdo"

!  UNRECOGNIZED;

    ELSE IF PARSETREE ≠ RNULL THEN
	COMERR("Can't generate code for this",PARSETREE);

    ENDLABEL:  !  This is here to avoid parse stack overflow;
    END "tscan";
END $$prgid;
!  Bugs

Global events will not work.

Extra variables are being generated for moves.	Can they be suppressed?
;