list_instructions(char *pfx, isn_T *instr, int instr_count, ufunc_T *ufunc)
{
    int		line_idx = 0;
    int		prev_current = 0;
    int		current;
    int		def_arg_idx = 0;

    for (current = 0; current < instr_count; ++current)
    {
	isn_T	    *iptr = &instr[current];
	char	    *line;

	if (ufunc != NULL)
	{
	    while (line_idx < iptr->isn_lnum
					  && line_idx < ufunc->uf_lines.ga_len)
	    {
		if (current > prev_current)
		{
		    msg_puts("\n\n");
		    prev_current = current;
		}
		line = ((char **)ufunc->uf_lines.ga_data)[line_idx++];
		if (line != NULL)
		    msg(line);
	    }
	    if (iptr->isn_type == ISN_JUMP_IF_ARG_SET)
	    {
		int	first_def_arg = ufunc->uf_args.ga_len
						   - ufunc->uf_def_args.ga_len;

		if (def_arg_idx > 0)
		    msg_puts("\n\n");
		msg_start();
		msg_puts("  ");
		msg_puts(((char **)(ufunc->uf_args.ga_data))[
						 first_def_arg + def_arg_idx]);
		msg_puts(" = ");
		msg_puts(((char **)(ufunc->uf_def_args.ga_data))[def_arg_idx++]);
		msg_clr_eos();
		msg_end();
	    }
	}

	switch (iptr->isn_type)
	{
	    case ISN_EXEC:
		smsg("%s%4d EXEC %s", pfx, current, iptr->isn_arg.string);
		break;
	    case ISN_EXEC_SPLIT:
		smsg("%s%4d EXEC_SPLIT %s", pfx, current, iptr->isn_arg.string);
		break;
	    case ISN_EXECRANGE:
		smsg("%s%4d EXECRANGE %s", pfx, current, iptr->isn_arg.string);
		break;
	    case ISN_LEGACY_EVAL:
		smsg("%s%4d EVAL legacy %s", pfx, current,
							 iptr->isn_arg.string);
		break;
	    case ISN_REDIRSTART:
		smsg("%s%4d REDIR", pfx, current);
		break;
	    case ISN_REDIREND:
		smsg("%s%4d REDIR END%s", pfx, current,
					iptr->isn_arg.number ? " append" : "");
		break;
	    case ISN_CEXPR_AUCMD:
#ifdef FEAT_QUICKFIX
		smsg("%s%4d CEXPR pre %s", pfx, current,
				       cexpr_get_auname(iptr->isn_arg.number));
#endif
		break;
	    case ISN_CEXPR_CORE:
#ifdef FEAT_QUICKFIX
		{
		    cexprref_T	    *cer = iptr->isn_arg.cexpr.cexpr_ref;

		    smsg("%s%4d CEXPR core %s%s \"%s\"", pfx, current,
				       cexpr_get_auname(cer->cer_cmdidx),
				       cer->cer_forceit ? "!" : "",
				       cer->cer_cmdline);
		}
#endif
		break;
	    case ISN_INSTR:
		{
		    smsg("%s%4d INSTR", pfx, current);
		    list_instructions("    ", iptr->isn_arg.instr,
								INT_MAX, NULL);
		    msg("     -------------");
		}
		break;
	    case ISN_SUBSTITUTE:
		{
		    subs_T *subs = &iptr->isn_arg.subs;

		    smsg("%s%4d SUBSTITUTE %s", pfx, current, subs->subs_cmd);
		    list_instructions("    ", subs->subs_instr, INT_MAX, NULL);
		    msg("     -------------");
		}
		break;
	    case ISN_EXECCONCAT:
		smsg("%s%4d EXECCONCAT %lld", pfx, current,
					      (varnumber_T)iptr->isn_arg.number);
		break;
	    case ISN_ECHO:
		{
		    echo_T *echo = &iptr->isn_arg.echo;

		    smsg("%s%4d %s %d", pfx, current,
			    echo->echo_with_white ? "ECHO" : "ECHON",
			    echo->echo_count);
		}
		break;
	    case ISN_EXECUTE:
		smsg("%s%4d EXECUTE %lld", pfx, current,
					  (varnumber_T)(iptr->isn_arg.number));
		break;
	    case ISN_ECHOMSG:
		smsg("%s%4d ECHOMSG %lld", pfx, current,
					  (varnumber_T)(iptr->isn_arg.number));
		break;
	    case ISN_ECHOCONSOLE:
		smsg("%s%4d ECHOCONSOLE %lld", pfx, current,
					  (varnumber_T)(iptr->isn_arg.number));
		break;
	    case ISN_ECHOERR:
		smsg("%s%4d ECHOERR %lld", pfx, current,
					  (varnumber_T)(iptr->isn_arg.number));
		break;
	    case ISN_LOAD:
		{
		    if (iptr->isn_arg.number < 0)
			smsg("%s%4d LOAD arg[%lld]", pfx, current,
				(varnumber_T)(iptr->isn_arg.number
							  + STACK_FRAME_SIZE));
		    else
			smsg("%s%4d LOAD $%lld", pfx, current,
					  (varnumber_T)(iptr->isn_arg.number));
		}
		break;
	    case ISN_LOADOUTER:
		{
		    if (iptr->isn_arg.number < 0)
			smsg("%s%4d LOADOUTER level %d arg[%d]", pfx, current,
				iptr->isn_arg.outer.outer_depth,
				iptr->isn_arg.outer.outer_idx
							  + STACK_FRAME_SIZE);
		    else
			smsg("%s%4d LOADOUTER level %d $%d", pfx, current,
					      iptr->isn_arg.outer.outer_depth,
					      iptr->isn_arg.outer.outer_idx);
		}
		break;
	    case ISN_LOADV:
		smsg("%s%4d LOADV v:%s", pfx, current,
				       get_vim_var_name(iptr->isn_arg.number));
		break;
	    case ISN_LOADSCRIPT:
		{
		    scriptref_T	    *sref = iptr->isn_arg.script.scriptref;
		    scriptitem_T    *si = SCRIPT_ITEM(sref->sref_sid);
		    svar_T	    *sv;

		    sv = get_script_svar(sref, -1);
		    if (sv == NULL)
			smsg("%s%4d LOADSCRIPT [deleted] from %s",
						    pfx, current, si->sn_name);
		    else
			smsg("%s%4d LOADSCRIPT %s-%d from %s", pfx, current,
					    sv->sv_name,
					    sref->sref_idx,
					    si->sn_name);
		}
		break;
	    case ISN_LOADS:
		{
		    scriptitem_T *si = SCRIPT_ITEM(
					       iptr->isn_arg.loadstore.ls_sid);

		    smsg("%s%4d LOADS s:%s from %s", pfx, current,
				 iptr->isn_arg.loadstore.ls_name, si->sn_name);
		}
		break;
	    case ISN_LOADAUTO:
		smsg("%s%4d LOADAUTO %s", pfx, current, iptr->isn_arg.string);
		break;
	    case ISN_LOADG:
		smsg("%s%4d LOADG g:%s", pfx, current, iptr->isn_arg.string);
		break;
	    case ISN_LOADB:
		smsg("%s%4d LOADB b:%s", pfx, current, iptr->isn_arg.string);
		break;
	    case ISN_LOADW:
		smsg("%s%4d LOADW w:%s", pfx, current, iptr->isn_arg.string);
		break;
	    case ISN_LOADT:
		smsg("%s%4d LOADT t:%s", pfx, current, iptr->isn_arg.string);
		break;
	    case ISN_LOADGDICT:
		smsg("%s%4d LOAD g:", pfx, current);
		break;
	    case ISN_LOADBDICT:
		smsg("%s%4d LOAD b:", pfx, current);
		break;
	    case ISN_LOADWDICT:
		smsg("%s%4d LOAD w:", pfx, current);
		break;
	    case ISN_LOADTDICT:
		smsg("%s%4d LOAD t:", pfx, current);
		break;
	    case ISN_LOADOPT:
		smsg("%s%4d LOADOPT %s", pfx, current, iptr->isn_arg.string);
		break;
	    case ISN_LOADENV:
		smsg("%s%4d LOADENV %s", pfx, current, iptr->isn_arg.string);
		break;
	    case ISN_LOADREG:
		smsg("%s%4d LOADREG @%c", pfx, current,
						  (int)(iptr->isn_arg.number));
		break;

	    case ISN_STORE:
		if (iptr->isn_arg.number < 0)
		    smsg("%s%4d STORE arg[%lld]", pfx, current,
				      iptr->isn_arg.number + STACK_FRAME_SIZE);
		else
		    smsg("%s%4d STORE $%lld", pfx, current,
							 iptr->isn_arg.number);
		break;
	    case ISN_STOREOUTER:
		{
		if (iptr->isn_arg.number < 0)
		    smsg("%s%4d STOREOUTEr level %d arg[%d]", pfx, current,
			    iptr->isn_arg.outer.outer_depth,
			    iptr->isn_arg.outer.outer_idx + STACK_FRAME_SIZE);
		else
		    smsg("%s%4d STOREOUTER level %d $%d", pfx, current,
			    iptr->isn_arg.outer.outer_depth,
			    iptr->isn_arg.outer.outer_idx);
		}
		break;
	    case ISN_STOREV:
		smsg("%s%4d STOREV v:%s", pfx, current,
				       get_vim_var_name(iptr->isn_arg.number));
		break;
	    case ISN_STOREAUTO:
		smsg("%s%4d STOREAUTO %s", pfx, current, iptr->isn_arg.string);
		break;
	    case ISN_STOREG:
		smsg("%s%4d STOREG %s", pfx, current, iptr->isn_arg.string);
		break;
	    case ISN_STOREB:
		smsg("%s%4d STOREB %s", pfx, current, iptr->isn_arg.string);
		break;
	    case ISN_STOREW:
		smsg("%s%4d STOREW %s", pfx, current, iptr->isn_arg.string);
		break;
	    case ISN_STORET:
		smsg("%s%4d STORET %s", pfx, current, iptr->isn_arg.string);
		break;
	    case ISN_STORES:
		{
		    scriptitem_T *si = SCRIPT_ITEM(
					       iptr->isn_arg.loadstore.ls_sid);

		    smsg("%s%4d STORES %s in %s", pfx, current,
				 iptr->isn_arg.loadstore.ls_name, si->sn_name);
		}
		break;
	    case ISN_STORESCRIPT:
		{
		    scriptref_T	    *sref = iptr->isn_arg.script.scriptref;
		    scriptitem_T    *si = SCRIPT_ITEM(sref->sref_sid);
		    svar_T	    *sv;

		    sv = get_script_svar(sref, -1);
		    if (sv == NULL)
			smsg("%s%4d STORESCRIPT [deleted] in %s",
						    pfx, current, si->sn_name);
		    else
			smsg("%s%4d STORESCRIPT %s-%d in %s", pfx, current,
					     sv->sv_name,
					     sref->sref_idx,
					     si->sn_name);
		}
		break;
	    case ISN_STOREOPT:
	    case ISN_STOREFUNCOPT:
		smsg("%s%4d %s &%s", pfx, current,
		  iptr->isn_type == ISN_STOREOPT ? "STOREOPT" : "STOREFUNCOPT",
					       iptr->isn_arg.storeopt.so_name);
		break;
	    case ISN_STOREENV:
		smsg("%s%4d STOREENV $%s", pfx, current, iptr->isn_arg.string);
		break;
	    case ISN_STOREREG:
		smsg("%s%4d STOREREG @%c", pfx, current,
						    (int)iptr->isn_arg.number);
		break;
	    case ISN_STORENR:
		smsg("%s%4d STORE %lld in $%d", pfx, current,
				iptr->isn_arg.storenr.stnr_val,
				iptr->isn_arg.storenr.stnr_idx);
		break;

	    case ISN_STOREINDEX:
		smsg("%s%4d STOREINDEX %s", pfx, current,
					  vartype_name(iptr->isn_arg.vartype));
		break;

	    case ISN_STORERANGE:
		smsg("%s%4d STORERANGE", pfx, current);
		break;

	    // constants
	    case ISN_PUSHNR:
		smsg("%s%4d PUSHNR %lld", pfx, current,
					    (varnumber_T)(iptr->isn_arg.number));
		break;
	    case ISN_PUSHBOOL:
	    case ISN_PUSHSPEC:
		smsg("%s%4d PUSH %s", pfx, current,
				   get_var_special_name(iptr->isn_arg.number));
		break;
	    case ISN_PUSHF:
#ifdef FEAT_FLOAT
		smsg("%s%4d PUSHF %g", pfx, current, iptr->isn_arg.fnumber);
#endif
		break;
	    case ISN_PUSHS:
		smsg("%s%4d PUSHS \"%s\"", pfx, current, iptr->isn_arg.string);
		break;
	    case ISN_PUSHBLOB:
		{
		    char_u	*r;
		    char_u	numbuf[NUMBUFLEN];
		    char_u	*tofree;

		    r = blob2string(iptr->isn_arg.blob, &tofree, numbuf);
		    smsg("%s%4d PUSHBLOB %s", pfx, current, r);
		    vim_free(tofree);
		}
		break;
	    case ISN_PUSHFUNC:
		{
		    char *name = (char *)iptr->isn_arg.string;

		    smsg("%s%4d PUSHFUNC \"%s\"", pfx, current,
					       name == NULL ? "[none]" : name);
		}
		break;
	    case ISN_PUSHCHANNEL:
#ifdef FEAT_JOB_CHANNEL
		{
		    channel_T *channel = iptr->isn_arg.channel;

		    smsg("%s%4d PUSHCHANNEL %d", pfx, current,
					 channel == NULL ? 0 : channel->ch_id);
		}
#endif
		break;
	    case ISN_PUSHJOB:
#ifdef FEAT_JOB_CHANNEL
		{
		    typval_T	tv;
		    char_u	*name;
		    char_u	buf[NUMBUFLEN];

		    tv.v_type = VAR_JOB;
		    tv.vval.v_job = iptr->isn_arg.job;
		    name = job_to_string_buf(&tv, buf);
		    smsg("%s%4d PUSHJOB \"%s\"", pfx, current, name);
		}
#endif
		break;
	    case ISN_PUSHEXC:
		smsg("%s%4d PUSH v:exception", pfx, current);
		break;
	    case ISN_UNLET:
		smsg("%s%4d UNLET%s %s", pfx, current,
			iptr->isn_arg.unlet.ul_forceit ? "!" : "",
			iptr->isn_arg.unlet.ul_name);
		break;
	    case ISN_UNLETENV:
		smsg("%s%4d UNLETENV%s $%s", pfx, current,
			iptr->isn_arg.unlet.ul_forceit ? "!" : "",
			iptr->isn_arg.unlet.ul_name);
		break;
	    case ISN_UNLETINDEX:
		smsg("%s%4d UNLETINDEX", pfx, current);
		break;
	    case ISN_UNLETRANGE:
		smsg("%s%4d UNLETRANGE", pfx, current);
		break;
	    case ISN_LOCKUNLOCK:
		smsg("%s%4d LOCKUNLOCK %s", pfx, current, iptr->isn_arg.string);
		break;
	    case ISN_LOCKCONST:
		smsg("%s%4d LOCKCONST", pfx, current);
		break;
	    case ISN_NEWLIST:
		smsg("%s%4d NEWLIST size %lld", pfx, current,
					    (varnumber_T)(iptr->isn_arg.number));
		break;
	    case ISN_NEWDICT:
		smsg("%s%4d NEWDICT size %lld", pfx, current,
					    (varnumber_T)(iptr->isn_arg.number));
		break;

	    // function call
	    case ISN_BCALL:
		{
		    cbfunc_T	*cbfunc = &iptr->isn_arg.bfunc;

		    smsg("%s%4d BCALL %s(argc %d)", pfx, current,
			    internal_func_name(cbfunc->cbf_idx),
			    cbfunc->cbf_argcount);
		}
		break;
	    case ISN_DCALL:
		{
		    cdfunc_T	*cdfunc = &iptr->isn_arg.dfunc;
		    dfunc_T	*df = ((dfunc_T *)def_functions.ga_data)
							     + cdfunc->cdf_idx;

		    smsg("%s%4d DCALL %s(argc %d)", pfx, current,
					    printable_func_name(df->df_ufunc),
							 cdfunc->cdf_argcount);
		}
		break;
	    case ISN_UCALL:
		{
		    cufunc_T	*cufunc = &iptr->isn_arg.ufunc;

		    smsg("%s%4d UCALL %s(argc %d)", pfx, current,
				       cufunc->cuf_name, cufunc->cuf_argcount);
		}
		break;
	    case ISN_PCALL:
		{
		    cpfunc_T	*cpfunc = &iptr->isn_arg.pfunc;

		    smsg("%s%4d PCALL%s (argc %d)", pfx, current,
			   cpfunc->cpf_top ? " top" : "", cpfunc->cpf_argcount);
		}
		break;
	    case ISN_PCALL_END:
		smsg("%s%4d PCALL end", pfx, current);
		break;
	    case ISN_RETURN:
		smsg("%s%4d RETURN", pfx, current);
		break;
	    case ISN_RETURN_VOID:
		smsg("%s%4d RETURN void", pfx, current);
		break;
	    case ISN_FUNCREF:
		{
		    funcref_T	*funcref = &iptr->isn_arg.funcref;
		    char_u	*name;

		    if (funcref->fr_func_name == NULL)
		    {
			dfunc_T	*df = ((dfunc_T *)def_functions.ga_data)
						       + funcref->fr_dfunc_idx;
			name = df->df_ufunc->uf_name;
		    }
		    else
			name = funcref->fr_func_name;
		    smsg("%s%4d FUNCREF %s", pfx, current, name);
		}
		break;

	    case ISN_NEWFUNC:
		{
		    newfunc_T	*newfunc = &iptr->isn_arg.newfunc;

		    smsg("%s%4d NEWFUNC %s %s", pfx, current,
				       newfunc->nf_lambda, newfunc->nf_global);
		}
		break;

	    case ISN_DEF:
		{
		    char_u *name = iptr->isn_arg.string;

		    smsg("%s%4d DEF %s", pfx, current,
					   name == NULL ? (char_u *)"" : name);
		}
		break;

	    case ISN_JUMP:
		{
		    char *when = "?";

		    switch (iptr->isn_arg.jump.jump_when)
		    {
			case JUMP_ALWAYS:
			    when = "JUMP";
			    break;
			case JUMP_NEVER:
			    iemsg("JUMP_NEVER should not be used");
			    break;
			case JUMP_AND_KEEP_IF_TRUE:
			    when = "JUMP_AND_KEEP_IF_TRUE";
			    break;
			case JUMP_IF_FALSE:
			    when = "JUMP_IF_FALSE";
			    break;
			case JUMP_AND_KEEP_IF_FALSE:
			    when = "JUMP_AND_KEEP_IF_FALSE";
			    break;
			case JUMP_IF_COND_FALSE:
			    when = "JUMP_IF_COND_FALSE";
			    break;
			case JUMP_IF_COND_TRUE:
			    when = "JUMP_IF_COND_TRUE";
			    break;
		    }
		    smsg("%s%4d %s -> %d", pfx, current, when,
						iptr->isn_arg.jump.jump_where);
		}
		break;

	    case ISN_JUMP_IF_ARG_SET:
		smsg("%s%4d JUMP_IF_ARG_SET arg[%d] -> %d", pfx, current,
			 iptr->isn_arg.jumparg.jump_arg_off + STACK_FRAME_SIZE,
						iptr->isn_arg.jump.jump_where);
		break;

	    case ISN_FOR:
		{
		    forloop_T *forloop = &iptr->isn_arg.forloop;

		    smsg("%s%4d FOR $%d -> %d", pfx, current,
					   forloop->for_idx, forloop->for_end);
		}
		break;

	    case ISN_TRY:
		{
		    try_T *try = &iptr->isn_arg.tryref;

		    if (try->try_ref->try_finally == 0)
			smsg("%s%4d TRY catch -> %d, endtry -> %d",
				pfx, current,
				try->try_ref->try_catch,
				try->try_ref->try_endtry);
		    else
			smsg("%s%4d TRY catch -> %d, finally -> %d, endtry -> %d",
				pfx, current,
				try->try_ref->try_catch,
				try->try_ref->try_finally,
				try->try_ref->try_endtry);
		}
		break;
	    case ISN_CATCH:
		smsg("%s%4d CATCH", pfx, current);
		break;
	    case ISN_TRYCONT:
		{
		    trycont_T *trycont = &iptr->isn_arg.trycont;

		    smsg("%s%4d TRY-CONTINUE %d level%s -> %d", pfx, current,
				      trycont->tct_levels,
				      trycont->tct_levels == 1 ? "" : "s",
				      trycont->tct_where);
		}
		break;
	    case ISN_FINALLY:
		smsg("%s%4d FINALLY", pfx, current);
		break;
	    case ISN_ENDTRY:
		smsg("%s%4d ENDTRY", pfx, current);
		break;
	    case ISN_THROW:
		smsg("%s%4d THROW", pfx, current);
		break;

	    // expression operations on number
	    case ISN_OPNR:
	    case ISN_OPFLOAT:
	    case ISN_OPANY:
		{
		    char *what;
		    char *ins;

		    switch (iptr->isn_arg.op.op_type)
		    {
			case EXPR_MULT: what = "*"; break;
			case EXPR_DIV: what = "/"; break;
			case EXPR_REM: what = "%"; break;
			case EXPR_SUB: what = "-"; break;
			case EXPR_ADD: what = "+"; break;
			default:       what = "???"; break;
		    }
		    switch (iptr->isn_type)
		    {
			case ISN_OPNR: ins = "OPNR"; break;
			case ISN_OPFLOAT: ins = "OPFLOAT"; break;
			case ISN_OPANY: ins = "OPANY"; break;
			default: ins = "???"; break;
		    }
		    smsg("%s%4d %s %s", pfx, current, ins, what);
		}
		break;

	    case ISN_COMPAREBOOL:
	    case ISN_COMPARESPECIAL:
	    case ISN_COMPARENR:
	    case ISN_COMPAREFLOAT:
	    case ISN_COMPARESTRING:
	    case ISN_COMPAREBLOB:
	    case ISN_COMPARELIST:
	    case ISN_COMPAREDICT:
	    case ISN_COMPAREFUNC:
	    case ISN_COMPAREANY:
		   {
		       char *p;
		       char buf[10];
		       char *type;

		       switch (iptr->isn_arg.op.op_type)
		       {
			   case EXPR_EQUAL:	 p = "=="; break;
			   case EXPR_NEQUAL:    p = "!="; break;
			   case EXPR_GREATER:   p = ">"; break;
			   case EXPR_GEQUAL:    p = ">="; break;
			   case EXPR_SMALLER:   p = "<"; break;
			   case EXPR_SEQUAL:    p = "<="; break;
			   case EXPR_MATCH:	 p = "=~"; break;
			   case EXPR_IS:	 p = "is"; break;
			   case EXPR_ISNOT:	 p = "isnot"; break;
			   case EXPR_NOMATCH:	 p = "!~"; break;
			   default:  p = "???"; break;
		       }
		       STRCPY(buf, p);
		       if (iptr->isn_arg.op.op_ic == TRUE)
			   strcat(buf, "?");
		       switch(iptr->isn_type)
		       {
			   case ISN_COMPAREBOOL: type = "COMPAREBOOL"; break;
			   case ISN_COMPARESPECIAL:
						 type = "COMPARESPECIAL"; break;
			   case ISN_COMPARENR: type = "COMPARENR"; break;
			   case ISN_COMPAREFLOAT: type = "COMPAREFLOAT"; break;
			   case ISN_COMPARESTRING:
						  type = "COMPARESTRING"; break;
			   case ISN_COMPAREBLOB: type = "COMPAREBLOB"; break;
			   case ISN_COMPARELIST: type = "COMPARELIST"; break;
			   case ISN_COMPAREDICT: type = "COMPAREDICT"; break;
			   case ISN_COMPAREFUNC: type = "COMPAREFUNC"; break;
			   case ISN_COMPAREANY: type = "COMPAREANY"; break;
			   default: type = "???"; break;
		       }

		       smsg("%s%4d %s %s", pfx, current, type, buf);
		   }
		   break;

	    case ISN_ADDLIST: smsg("%s%4d ADDLIST", pfx, current); break;
	    case ISN_ADDBLOB: smsg("%s%4d ADDBLOB", pfx, current); break;

	    // expression operations
	    case ISN_CONCAT: smsg("%s%4d CONCAT", pfx, current); break;
	    case ISN_STRINDEX: smsg("%s%4d STRINDEX", pfx, current); break;
	    case ISN_STRSLICE: smsg("%s%4d STRSLICE", pfx, current); break;
	    case ISN_BLOBINDEX: smsg("%s%4d BLOBINDEX", pfx, current); break;
	    case ISN_BLOBSLICE: smsg("%s%4d BLOBSLICE", pfx, current); break;
	    case ISN_LISTAPPEND: smsg("%s%4d LISTAPPEND", pfx, current); break;
	    case ISN_BLOBAPPEND: smsg("%s%4d BLOBAPPEND", pfx, current); break;
	    case ISN_LISTINDEX: smsg("%s%4d LISTINDEX", pfx, current); break;
	    case ISN_LISTSLICE: smsg("%s%4d LISTSLICE", pfx, current); break;
	    case ISN_ANYINDEX: smsg("%s%4d ANYINDEX", pfx, current); break;
	    case ISN_ANYSLICE: smsg("%s%4d ANYSLICE", pfx, current); break;
	    case ISN_SLICE: smsg("%s%4d SLICE %lld",
				    pfx, current, iptr->isn_arg.number); break;
	    case ISN_GETITEM: smsg("%s%4d ITEM %lld%s", pfx, current,
					 iptr->isn_arg.getitem.gi_index,
					 iptr->isn_arg.getitem.gi_with_op ?
						       " with op" : ""); break;
	    case ISN_MEMBER: smsg("%s%4d MEMBER", pfx, current); break;
	    case ISN_STRINGMEMBER: smsg("%s%4d MEMBER %s", pfx, current,
						  iptr->isn_arg.string); break;
	    case ISN_CLEARDICT: smsg("%s%4d CLEARDICT", pfx, current); break;
	    case ISN_USEDICT: smsg("%s%4d USEDICT", pfx, current); break;

	    case ISN_NEGATENR: smsg("%s%4d NEGATENR", pfx, current); break;

	    case ISN_CHECKNR: smsg("%s%4d CHECKNR", pfx, current); break;
	    case ISN_CHECKTYPE:
		  {
		      checktype_T *ct = &iptr->isn_arg.type;
		      char *tofree;

		      if (ct->ct_arg_idx == 0)
			  smsg("%s%4d CHECKTYPE %s stack[%d]", pfx, current,
					  type_name(ct->ct_type, &tofree),
					  (int)ct->ct_off);
		      else
			  smsg("%s%4d CHECKTYPE %s stack[%d] arg %d",
					  pfx, current,
					  type_name(ct->ct_type, &tofree),
					  (int)ct->ct_off,
					  (int)ct->ct_arg_idx);
		      vim_free(tofree);
		      break;
		  }
	    case ISN_CHECKLEN: smsg("%s%4d CHECKLEN %s%d", pfx, current,
				iptr->isn_arg.checklen.cl_more_OK ? ">= " : "",
				iptr->isn_arg.checklen.cl_min_len);
			       break;
	    case ISN_SETTYPE:
		  {
		      char *tofree;

		      smsg("%s%4d SETTYPE %s", pfx, current,
			      type_name(iptr->isn_arg.type.ct_type, &tofree));
		      vim_free(tofree);
		      break;
		  }
	    case ISN_COND2BOOL: smsg("%s%4d COND2BOOL", pfx, current); break;
	    case ISN_2BOOL: if (iptr->isn_arg.tobool.invert)
				smsg("%s%4d INVERT %d (!val)", pfx, current,
					 iptr->isn_arg.tobool.offset);
			    else
				smsg("%s%4d 2BOOL %d (!!val)", pfx, current,
					 iptr->isn_arg.tobool.offset);
			    break;
	    case ISN_2STRING: smsg("%s%4d 2STRING stack[%lld]", pfx, current,
				 (varnumber_T)(iptr->isn_arg.tostring.offset));
			      break;
	    case ISN_2STRING_ANY: smsg("%s%4d 2STRING_ANY stack[%lld]",
								  pfx, current,
				 (varnumber_T)(iptr->isn_arg.tostring.offset));
			      break;
	    case ISN_RANGE: smsg("%s%4d RANGE %s", pfx, current,
							 iptr->isn_arg.string);
			    break;
	    case ISN_PUT:
	        if (iptr->isn_arg.put.put_lnum == LNUM_VARIABLE_RANGE_ABOVE)
		    smsg("%s%4d PUT %c above range",
				  pfx, current, iptr->isn_arg.put.put_regname);
		else if (iptr->isn_arg.put.put_lnum == LNUM_VARIABLE_RANGE)
		    smsg("%s%4d PUT %c range",
				  pfx, current, iptr->isn_arg.put.put_regname);
		else
		    smsg("%s%4d PUT %c %ld", pfx, current,
						 iptr->isn_arg.put.put_regname,
					     (long)iptr->isn_arg.put.put_lnum);
		break;

	    case ISN_CMDMOD:
		{
		    char_u  *buf;
		    size_t  len = produce_cmdmods(
				  NULL, iptr->isn_arg.cmdmod.cf_cmdmod, FALSE);

		    buf = alloc(len + 1);
		    if (likely(buf != NULL))
		    {
			(void)produce_cmdmods(
				   buf, iptr->isn_arg.cmdmod.cf_cmdmod, FALSE);
			smsg("%s%4d CMDMOD %s", pfx, current, buf);
			vim_free(buf);
		    }
		    break;
		}
	    case ISN_CMDMOD_REV: smsg("%s%4d CMDMOD_REV", pfx, current); break;

	    case ISN_PROF_START:
		 smsg("%s%4d PROFILE START line %d", pfx, current,
							       iptr->isn_lnum);
		 break;

	    case ISN_PROF_END:
		smsg("%s%4d PROFILE END", pfx, current);
		break;

	    case ISN_DEBUG:
		smsg("%s%4d DEBUG line %d-%d varcount %lld", pfx, current,
			iptr->isn_arg.debug.dbg_break_lnum + 1,
			iptr->isn_lnum,
			iptr->isn_arg.debug.dbg_var_names_len);
		break;

	    case ISN_UNPACK: smsg("%s%4d UNPACK %d%s", pfx, current,
			iptr->isn_arg.unpack.unp_count,
			iptr->isn_arg.unpack.unp_semicolon ? " semicolon" : "");
			      break;
	    case ISN_SHUFFLE: smsg("%s%4d SHUFFLE %d up %d", pfx, current,
					 iptr->isn_arg.shuffle.shfl_item,
					 iptr->isn_arg.shuffle.shfl_up);
			      break;
	    case ISN_DROP: smsg("%s%4d DROP", pfx, current); break;

	    case ISN_FINISH: // End of list of instructions for ISN_SUBSTITUTE.
			   return;
	}

	out_flush();	    // output one line at a time
	ui_breakcheck();
	if (got_int)
	    break;
    }
}