When the Natural Optimizer has been activated, you can specify checks by setting the options explained in this section.
The options cannot be used for specifying statements to be optimized.
This document covers the following topics:
The following table lists and describes the Natural Optimizer Compiler options. Default values are underlined (this is the value that will be assumed if the option is not present).
A Natural Optimizer Compiler option consists of a string
surrounded by brackets or single quotation marks (except in the Natural
OPTIONS statement),
with options separated by commas. Some options have values, while the very
existence of some options in the option string is sufficient to modify the
environment.
The following rules apply:
Optional clauses are surrounded by square brackets [ ].
Choices are surrounded by curly braces { }.
Each choice is separated by vertical lines "|".
Only one of these choices can be specified;
ON is equivalent to Y (Yes),
OFF to N (No).
Options specified without the optional clause ON
or OFF (if applicable), or their equivalent values, are
interpreted as set to ON. For example, OVFLW is
identical to OVFLW=ON.
Except for the option OFF, any specified option
switches on optimizing (as if ON was specified) and the default
values apply. For example, INDEX is identical to
ON,INDEX.
| Option | Explanation |
|---|---|
ABEND |
Forces the Natural Optimizer Compiler to generate code
which causes Natural to be abnormally terminated immediately when the
ABEND option is encountered by the Natural Optimizer Compiler
during compilation. The option must appear by itself or it will be ignored.
Other parameters are not changed or reset by this option. This option can be
useful for debugging purposes.
|
ARCH |
Specifies the architecture level to be used for code generation: see ARCH Option in the following section. |
ARROPT |
Specifies
the generation to be used for array assignments of the type
A(*):=scalar. See
ARROPT Option
in the following section.
|
CACHE[={ON| OFF |Y|N}] |
Switches variable caching on or off. See also Variable Caching in the section Performance Considerations. |
CPU= /370 |
Specifies the target architecture. |
DIGTCHCK[={ON| OFF |Y|N}] |
Specifies whether the
digits of packed and unpacked numeric fields (formats P and N) are to be
checked when moving to another variable of the same type and precision. For
example, if DIGTCHCK is ON and an
unpacked numeric variable (format N) contains an invalid digit, such as
X'FA', moving to another unpacked numeric variable with the same
precision will generate a S0C7 (or NAT0954) error. If
DIGTCHCK is OFF, no error is generated but the
generated code is much faster.
|
ERRDUMP[={ON| OFF |Y|N}] |
Specifies whether NOC should abend if an error condition is detected during the compile phase. This is useful for debugging the Natural Optimizer Compiler itself. |
INDEX[={ON| OFF |Y|N}] |
Specifies whether array indexes will be checked for
out-of-bound values in the optimized code.
See also the following Note. |
INDX[={ON| OFF |Y|N}] |
Specifies whether array indexes will be checked for
out-of-bound values in the optimized code.
Additionally, See also the following Note. |
IO[={ON| OFF|Y|N}] |
Provided for compatibility reasons only. No effect. |
LOOPS[={ON| OFF |Y|N}] |
Provided for compatibility reasons only. No effect. |
MIX[={ON| OFF |Y|N}] |
Provided for compatibility reasons only. No effect. |
NODBG[={ON|
OFF|Y|N}] |
If NODBG=OFF/N (default), the Natural
Debugger can be used to debug optimized code (then, additional code is
generated to check whether TEST mode has been set on).
If See also |
NOSGNTR[={ON| OFF |Y|N}] |
Applies to packed numbers only.
If |
ON |
Switches on optimizing. If no additional option is
specified, the default value defined for each option is in effect. As indicated
in the following Note, this may cause
unintended results, in particular regarding the options INDEX, INDX,
OVFLW, and RANGE.
|
OFF |
Switches off optimizing. |
OPTLEV={ 2|3} |
Specifies optimization level - roughly equivalent to
the number of passes through the program.
|
OVFLW[={ON| OFF |Y|N}] |
Specifies whether checks for overflow in arithmetic
operations or assignments will be included in the optimized code.
See also the following Note. |
PGEN[={ON| OFF |Y|N}] |
Specifies whether a disassembly of the optimized code should be output. This option also enables all other tracing options: see PGEN Option in the following section. |
RANGE[={ON| OFF |Y|N}] |
Specifies whether range checks will be performed in
operations with arrays. This ensures that array ranges will have an equal
number of elements in corresponding dimensions of all operands.
See also the following Note. |
SIGNCHCK[={
ON|OFF|Y|N}] |
Specifies whether the result of a multiplication with
a packed or unpacked numeric multiplier should be checked for a negative zero.
If zero is multiplied by a negative number, the MP machine instruction
generates a negative zero result. If SIGNCHCK is on, this negative
zero is converted to a positive zero. The check for a negative zero is done for
every multiplication with a packed or unpacked numeric multiplier.
|
TRENTRY |
For internal use by Software AG only. Do not change the setting of this parameter. |
UNICC |
Specifies
whether optimized code is generated for IF and DECIDE
statements with Unicode operands: see UNICC Option in
the following section.
|
ZD[={
ON|OFF|Y|N}] |
Specifies whether divisors should be checked for zero.
If this option is specified, then code is inserted, so that the program behaves
according to the ZD profile parameter of
Natural, that is, Natural error NAT1302 is issued or the result is
zero. If this option is not specified, Natural error NAT0954
occurs if the divisor is zero.
See also ZD - Zero-Division Check in the Natural Parameter Reference documentation. |
Note for INDEX, INDX, OVFLW and RANGE:
If the option INDEX, INDX,
OVFLW or RANGE is set, extra instructions are added
to the generated code to detect data overflow and index-out-of-range situations
should they occur during program execution. Although the use of these options
slightly increases the generated code, we recommend to use them to guarantee
that erroneous programs are detected and cannot lead to unpredictable results,
storage corruptions or abnormal program terminations.
Below is information on:
DEFINE DATA LOCAL ... 1 P1 (P1/9) ... 1 P3 (P3/9) ... 1 I (I4) 1 J (I4) 1 K (I4) 1 L (I4) END-DEFINE ... P1(I:J) := P3(K:L) ... END
With INDX=ON or INDEX=ON set, code is
generated to verify that I, J, K and
L are within the ranges defined for P1 and
P3 respectively.
With INDX=ON or RANGE=ON set, code is
generated to verify that I:J and K:L denote ranges of
the same length.
With OVFLW=ON set, code is generated to verify that
the value of P3 fits into the corresponding P1
variable.
For example: Value 100 would cause an overflow
here.
Example Error Situation:
If one of the occurrences of P3 contains the value
100, with OVFLW=OFF set, the value assigned to the
corresponding P1 occurrence will be zero. If the index variable
I is zero or greater than 9, with
INDX=OFF set, storage areas that do not belong to Array
P1 will be corrupted. If these options (OVFLW and
INDX) are set to ON, a Natural error occurs like it
does in standard Natural runtime.
For the NOC option specified above, additional code is generated. However, this is well compensated for by the advantage of a check that, for example, protects against hard-to-debug errors. Undetected errors can, of course, lead to unpredictable results.
To assure that the least amount of code is generated and thus achieve optimum performance, use:
OPT='NODBG,NOSGNTR,SIGNCHCK=OFF,ZD=OFF'
However, only apply this setting to objects that have been thoroughly debugged; see also Note for INDEX, INDX, OVFLW and RANGE.
The ARROPT option determines the generation algorithm
to be used for array assignments of the type
A(*):=scalar.
Valid values for ARROPT are:
| Value | Explanation |
|---|---|
ON |
Recommended setting for arrays with a
minimum of 50 occurrences.
|
OFF |
Recommended setting for arrays with less than 50 occurrences. |
The PGEN option causes the Natural Optimizer Compiler
to output the generated code and internal Natural structures. Thus, code and
structures can be examined, for example, for bug fixing, performance review and
support issues.
An understanding of IBM's /370 assembler is required to interpret
the results produced by the PGEN option.
We recommend that you use this option with the assistance of your local Software AG representative.
Below is information on:
To use the PGEN facility, set the PGEN
option when activating on the Optimizer Compiler.
Since the buffer is kept in memory, it is possible that the user
thread will not be big enough to hold the trace information. In this case, try
setting PGEN on only for the portion of the program which is to be
traced, for example:
OPTIONS
MCG=(PGEN=ON,TRGPT=ON)or OPTIONS MCG=+PGEN,TRGPT |
Turns tracing on, including tracing of the GPT entries |
OPTIONS MCG=(PGEN=OFF)or OPTIONS MCG=-PGEN |
Turns tracing off |
Various options affect the content of the output. The basic
PGEN option causes a formatted listing of Natural source lines and
a disassembly of the corresponding code to be generated and kept in memory for
extraction by the NOCSHOW utility as described below, under
Output of the PGEN
Option.
The TRSTMT, TRGPT, TRMPT
and TRVDT options cause hex dumps of internal data structures
associated with each line to be output.
The TRBASES and TRCACHE options cause
information on base registers and cache variables to be printed out.
The following table describes the options when
PGEN=ON. For an explanation of the syntax used see the
introduction to List of
Options above.
| Option | Explanation |
|---|---|
LPP={5|..| 55 |..|255} |
Lines-per-page for the trace output, only used when
TREXT=ON.
|
NOsrcE[={ON| OFF |Y|N}] |
If NOsrcE=OFF, the Natural source
statement is included in the output.
|
TRACELEV={ 0 |..|255} |
Specifies the trace level. Each bit in this one byte
value specifies a buffer type to trace; these bits can be set on by using the
TRxxx options as well.
|
TRBASES[={ON| OFF |Y|N}] |
Specifies whether base register allocations are traced. |
TRCACHE[={ON|
OFF|Y|N}] |
Specifies whether CACHE entries are
traced.
|
TREXT[={ON| OFF |Y|N}] |
If TREXT=ON, trace is directed to the
user exit NOCPRINT as described
below.
|
TRGPT[={ON| OFF |Y|N}] |
Specifies whether GPT entries are
traced.
|
TRMPT[=ON| OFF |Y|N}] |
Specifies whether MPT entries are
traced.
|
TRSTMT[={ON| OFF |Y|N}] |
Specifies whether STMT entries are
traced.
|
TRVDT[={ON| OFF |Y|N}] |
Specifies whether VDT entries are
traced.
|
See also the examples below.
There are two places to where the Natural Optimizer Compiler can
direct the output of PGEN:
The contents of this buffer is overwritten each time a
CHECK, CAT,
STOW or RUN command is
executed. A system utility NOCSHOW is provided whereby the
contents of this buffer can be viewed, searched or printed.
To invoke the NOCSHOW utility
Enter the direct command
NOCSHOW after a CHECK,
STOW, CAT or
RUN where the Natural Optimizer Compiler has been
active.
The following PF keys are available on the screen:
| PF Key | Function |
|---|---|
| PF2 | Position to top of output |
| PF4 | Position one line backward |
| PF5 | Position one line forward |
| PF6 | Print to report (1) |
| PF7 | Position one page backward |
| PF8 | Position one page forward |
| PF9 | Print via Entire Connection to report (7) |
| PF10 | Scan for text string |
| PF11 | Repeat scan |
If TREXT=ON is specified, the Natural Optimizer
Compiler passes every output line to the user exit NOCPRINT
instead of adding it to the trace buffer.
NOCPRINT is invoked following normal OS register
conventions. Register 1 points to a full word containing the address of the 81
byte print line with ANSI carriage control characters in position 1. Register
13 points to an area of 18*4 bytes which may be used as a save area. Register
14 contains the return address and Register 15 contains the entry address of
NOCPRINT.
The user exit NOCPRINT can be written in any
language which supports the register conventions described above. It must be
linked to the Natural nucleus together with the Natural Optimizer Compiler
nucleus.
This section provides hints and explanations on how to interpret
the output created with the PGEN option.
At the top of the PGEN output are some
disassembled lines which do not appear to belong to any source line. These are
the instructions which make up the prologue, which is executed whenever control
passes from non-optimized to optimized code. Permanent base registers are
loaded and control is passed to the correct point in the prologue. See
Example Section
A below.
Sometimes a lot of source lines are printed without any code. This indicates that there was no code required or that these statements are excluded from the NOC optimization. See Example Section B below.
Moreover, when the code generated for a Natural statement consists only of:
BAS R14,RETH DC X'....'
this indicates a return back to the standard runtime, as
this statement could not be NOC optimized (see line 0170).
If the NODBG=OFF (default) has been specified,
a sequence of instructions is generated at the start of each Natural
statement:
BALR R9,R11 DC X'....'
This sequence sets the line number (in case of error) and
checks whether the TEST mode is switched ON. Without
this sequence, debugging of NOC-compiled statements by the Natural
Debugger is not
possible. See Example Section
C below.
Sometimes there is a line break between disassembled lines. This break indicates an internal statement separation. It happens because often a single Natural statement will generate multiple internal (pseudo-code) statements.
The Natural variables operated are inserted in the Assembler code.
The items on the right side (e.g. “START 8FEC”) are of internal nature. They document the path how the code was generated by the NOC modules.
All kind of addresses inside the code are resolved and
provided in the form “=(00044)”. It documents the offset in the
code to which the branch is executed.
The first and the last code instruction contains the NOC
version used to compile this program. The meaning of “4700
8410” is NOC V841.
000000 4700 8410 NOP 1040(,R8) START 8FEC
000004 5880 D354 L R8,CONST D9DC
000008 5870 D370 L R7,LOCAL D9DC
00000C 4810 6006 LH R1,6(,R6) 90A0
000010 1F60 SLR R6,R0 90BA
000012 47F1 A000 B 0(R1,R10) 90C0
000016 4DE0 B040 BAS R14,RETH RETN F0AA
00001A 0034 DC X'0034' F0C0
0010 0010 OPTIONS MCG=(PGEN,OVFLW,INDX) 0020 DEFINE DATA LOCAL 0030 1 I(I4) 0040 1 P(P7.2) 0050 1 T(P7.2) 0060 END-DEFINE 0070 * 0080 SETTIME 0090 *
0100 FOR I=1 TO 100000
00001C 0D9B BASR R9,R11 MOVE 1724A
00001E 004A DC X'004A' 17278
000020 D203 7000 8148 MVC I(4),#KST0148 97D2
000026 47F0 A044 B 68(,R10) =(00044) GOTO EF44
00002A 0D9B BASR R9,R11 ADD 1724A
00002C 006A DC X'006A' 17278
00002E BF0F 7000 ICM R0,B'1111',I BB20
000032 5A00 8148 A R0,#KST0148 1E4E
000036 0D90 BASR R9,0 F12A
000038 4710 B15C BO NAT1301 1E9E
00003C BE0F 7000 STCM R0,B'1111',I A9CC
000040 0D9B BASR R9,R11 IF 1724A
000042 007C DC X'007C' 17278
000044 BF0F 7000 ICM R0,B'1111',I BB20
000048 5900 819B C R0,#KST019B 3FDA
00004C 47D0 A054 BNH 84(,R10) =(00054) EF44
000050 47F0 A078 B 120(,R10) =(00078) GOTO EF44
0110 ADD 1.00 TO P
000054 0D9B BASR R9,R11 ADD 1724A
000056 0092 DC X'0092' 17278
000058 FA41 7004 819F AP P(5),#KST019F(2) 20A0
00005E 0D90 BASR R9,0 F12A
000060 4710 B15C BO NAT1301 1071C
000064 910D 7008 TM P+4,X'0D' 120B0
000068 4710 A070 BO 112(,R10) =(00070) 120F6
00006C 960F 7008 OI P+4,X'0F' 1210ª
0120 END-FOR
0130 *
000070 0D9B BASR R9,R11 GOTO 1724A
000072 00A4 DC X'00A4' 17278
000074 47F0 A02A B 42(,R10) =(0002A) EF44
0140 T:=*TIMD(0080)
000078 0D9B BASR R9,R11 SYFU 1724A
00007A 00AE DC X'00AE' 17278
00007C 4DE0 B0D8 BAS R14,SYSFUNC 5F1A
000080 0190 B881 DC X'0190B881' 5F28
000084 F246 7009 8190 PACK T(5),#KST0190(7) MOVE AD18
00008A 910F 700D TM T+4,X'0F' 12130
00008E 4710 A0A0 BO 160(,R10) =(000A0) 12176
000092 17EE XR R14,R14 1218E
000094 43E0 700D IC R14,T+4 12194
000098 43EE B488 IC R14,PSGNTR(R14) 121AA
00009C 42E0 700D STC R14,T+4 121B2
0000A0 F040 7009 0002 SRP T(5),2,0 ACA2
0000A6 17EE XR R14,R14 1218E
0000A8 43E0 700D IC R14,T+4 12194
0000AC 43EE B488 IC R14,PSGNTR(R14) 121AA
0000B0 42E0 700D STC R14,T+4 121B2
0150 T:=T / 10
0160 *
0000B4 0D9B BASR R9,R11 DIV 1724A
0000B6 00C0 DC X'00C0' 17278
0000B8 F864 D100 7009 ZAP OP1(7),T(5) AC60
0000BE FD61 D100 81A1 DP OP1(7),#KST01A1(2) 327A
0000C4 F844 7009 D100 ZAP T(5),OP1(5) AC60
0000CA 910D 700D TM T+4,X'0D' 120B0
0000CE 4710 A0D6 BO 214(,R10) =(000D6) 120F6
0000D2 960F 700D OI T+4,X'0F' 1210A
0170 DISPLAY 'ELAPSED TIME (S)' T
0000D6 4DE0 B040 BAS R14,RETH RETN F0AA
0000DA 00D2 DC X'00D2' F0C0
0180 END
0000DC 40D6 D7E3 F844 2000 DC X'40D6D7E3F8442000' =' OPT8à..' END 927E
0000E4 0000 0000 DC X'00000000' nf
0000E8 40D5 D6C3 F8F4 F140 DC X'40D5D6C3F8F4F140' =' NOC841 ' 92E4
The global parameter ZD influences the
behavior of the NOC compiler. See the description of the
ZD option as
described under List of
Options above.
The COMPOPT parameter PSIGNF
(see also the system command COMPOPT in
the Natural System Commands documentation) influences the
behavior by forcing the signs of positive packed decimal numbers to F if
ON, and to C if OFF. The parameter is applied if
NOSGNTR=OFF is specified.
See the chart below for packed data (Format P) ":"
NOSGNTR=OFF |
and | PSIGNF=ON |
All signs are normalized to F (default). |
NOSGNTR=OFF |
and | PSIGNF=OFF |
All signs are normalized to C. |
NOSGNTR=ON |
All signs are left as they were generated by the last operation. | ||
For numeric data (Format N) the signs are always normalized to F,
regardless of the settings of NOSGNTR and
PSIGNF.