JPH0560616B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] The address of a parameter and the address of a parameter specification variable indicating which parameter the parameter is and which parameter is omitted are sent to the call destination. This is a program call method that notifies the program.

[Industrial application field]

The present invention relates to a program calling method that allows the parameter packet area used when passing necessary data to a called program to be concise.

[Conventional technology]

FIG. 9 is a diagram for explaining the outline of the compiler. In the figure, 1 is a preprocessor, 2
indicate the respective processors. As shown in FIG. 10, the preprocessor 1 has a function of converting macro descriptions in a source program into CALL statements. In the example in Figure 10, the CALL statement is
It has an entry name XYZ and arguments X, X ₁ , ..., X _o . Although not shown, the procedure
XYZ has parameters X', _X1 ',..., Xo _' corresponding to the arguments X, _X1 ,..., _Xo . FIG. 11 is a diagram illustrating conversion from a conventional macro to a CALL statement. Figure 11a shows the CALL statement when the macro operand is not omitted, and Figure 11b
CALL when the macro operand is omitted
It shows the sentence. That is, when an operand of a macro is omitted, 0 is written in the position corresponding to the omitted operand in the argument list of the CALL statement.

[Problem to be solved]

In the conventional method, when many operands are omitted and later operands are specified, many 0s appear in the argument list of the CALL statement, which is unsightly. Additionally, the parameter packet area used when passing parameters to the called program has become larger.

The present invention was created in view of this point, and an object of the present invention is to simplify the parameter packet area used when passing to a called program.

[Means for solving problems]

FIG. 1 is a diagram showing the principle of the present invention. The calling program notifies the called program of the address of the parameter and the address of the parameter specification variable. The parameter specification variable indicates which parameter is the passed parameter and also indicates which parameter is omitted. If the passed parameter is the i-th one, the i-th bit of the parameter specification variable is 1.
If the jth parameter is omitted, the jth bit of the parameter specification variable is set to 0. The last bit of the parameter specification variable is a parameter address invariant indication bit.
A parameter address unchanged indicator bit of 1 indicates that the parameter address is unchanged from the previous call, and a parameter address unchanged indicator bit of 0 indicates that the parameter address is different from the previous call.

〔Example〕

FIG. 2 is a diagram showing the process of converting a macro into a CALL statement. Before explaining the CALL conversion process, the names and symbols used in FIG. 2 will be explained.
FIG. 3 is a diagram illustrating parameter specification variables.
If the i-th bit of the parameter specification variable is on, it means that the i-th parameter PARMi is specified. In the present invention, a common area is provided for saving and restoring parameters and addresses. Second
This is COMMON in the figure. x||y means to connect the content of x and the content of y. For example, if x is ABC and y is DE, then x‖y is
It becomes ABCDE. FIG. 4 is a diagram explaining ANS. ANS means that the string generated by the macro is output at the position where the macro is written.

The process shown in FIG. 2 will be explained. At first,
COMMON, PARM1 (p1), PARM2 (p2),...
Reads the operands PARMn (pn) and UNCHANGED, and then initializes the parameter specification variables and generated parameter strings. After the initialization process,
It is checked whether PARM1 (p1) is specified, and if so, the parameter specification variable is set to "100...00"B, and the generated parameter string is set to p1. After completing the processing for PARM (p1), check whether PARM2 (p2) is specified, and if so, use the logical OR of the parameter specification variable and “010…00”B to create a new parameter specification. A new generation parameter sequence is created by concatenating the generation parameter sequence and p2 as a variable.
If PARMi(pi) is specified, the new parameter specification variable is the logical sum of the parameter specification variable and a bit string in which the i-th bit is 1 and the rest are 0 (length is n+1), and the generation parameter is The concatenation of the sequence and pi becomes a new generation parameter sequence. Repeat the same process up to PARMn. Next, it is checked whether there is an UNCHANGED designation, and if there is, the logical sum of the parameter designation variable and a bit string in which the (n+1)th bit (last bit) is 1 and the rest are 0 is used as the parameter designation variable. Finally, as shown by ANS in Figure 2, characters, symbols, etc. are concatenated to generate a CALL statement. The conversion process to the CALL statement shown in FIG. 2 is performed by the preprocessor 1. For example, what about macros? GET COMAREA PAPM1(IN1)
PARM3 (IN3) PARM64 (IN64)
UNCHANGED;, the CALL statement is CALL GETRTN(“1010000…00011”B,
COMAREA, IN1, IN3, IN64);

FIG. 5 is a diagram showing an example of the translation result of a CALL statement. This translation result is the above CALL statement, i.e.
CALL GETRTN(“1010000…00011”B,
COMAREA, IN1, IN3, IN64); is obtained when translated. In FIG. 5, ppa indicates the start address of the parameter packet area. This translation result is obtained by loading the address of the parameter packet area into general-purpose register R1,
Loads the branch destination address into general-purpose register R15, branches to the branch destination address specified by general-purpose register R15, and instructs to return to the address in general-purpose register R14 after the called destination process is completed. The parameter packet area means an area for storing parameter specification variables, a common area, and parameter addresses. Note that the CALL statement is translated by the processor 2.

When you perform the CALL statement conversion process as shown in Figure 2,
The CALL statement becomes more concise and the parameter packet area becomes smaller, but this has the disadvantage that it takes time to reference the parameters at the callee. If the processing of the called module requires a large number of travel steps, the number of travel steps required to refer to a parameter is relatively low, but if the processing requires a small number of travel steps, the number of travel steps is relatively high. Therefore, if the parameters do not change between the first and second calls, the parameter address is stored in the parameter pointer area at the first call, and the parameter address is stored in the parameter pointer area.
The address is saved in the common area, and from the second time onwards, the parameter address in the common area is restored to the parameter pointer area and used.

FIG. 6 is a diagram showing the structure of the called program. The called program consists of a part that takes out parameters, saves and restores them, and a part that performs the actual processing of the program. Retrieving parameters is
PARM1, PARM2, ..., pointer to PARMn (for example, an array called PARMPTR with upper limit n)
PARMPTR(1), PARMPTA(2),...
PARMPTA(n) has those addresses). If PARMi is not specified,
Set PARMPTR(i) to 0 instead of that address.

Note that the called program already knows the parameters that may be omitted, and first determines whether they have been specified before referencing them. this is
This can be determined by whether PARMPTR(i) is 0 or not. If the parameter is omitted, the called program will process accordingly. For example, if the specification specifies that a default value is assigned to a parameter when the parameter is omitted, processing for assigning the default value to the parameter is performed.

FIG. 7 is a diagram showing the configuration of the common area. As shown in FIG. 7, an array called PARMADDR with an upper limit of n saves the addresses of PARM1, PARM2, . . . PARMn. The "flag indicating whether the data has been saved or not" in the common area is initially off. When off, the parameter address unchanged display
When a CALL statement comes, extract and save the parameters, and turn on the ``saved or not saved flag.''
However, if a CALL statement that does not display parameter address unchanged even once is received, the saved parameter address will become invalid, so extract the parameter again and turn off the ``saved flag''. do.

FIG. 8 is a diagram illustrating parameter extraction and save/restore processing.

As shown in FIG. 8, when there is an indication that the parameter address is unchanged in the parameter packet area and the "saved or not saved flag" in the common area is on, the parameter is restored. To restore the parameters,
This is performed by writing the contents of the array element specified by the counter ctr1 in the array PARMADDR to the array element specified by the counter ctr1 in the array PARMPTR while changing the value of the counter ctr1 from 1 to n.

When there is an indication that the parameter address is unchanged in the parameter packet area and the "saved or not saved flag" in the common area is off, the parameter is taken out and saved. Parameter saving and restoration processing is performed as follows. First, set the value of counter ctr2 to 3. Then, if the bit specified by counter ctr1 in the parameter specification variable is on,
Writes the data at the address specified by counter ctr2 in the parameter packet area ppa to the array element specified by counter ctr1 in the array PARMPTR, and writes the data at the address specified by counter ctr2 in the parameter packet area ppa to the array element specified by counter ctr1 in the array PARMPTR.
Array the data at the address specified in 2.
Write to the array element specified by counter ctr1 in PARMADDR and update the value of counter ctr2. If the bit specified by counter ctr1 in the parameter specification variable is off, the array
Write 0 to the array element specified by counter ctr1 in PARMPTR, and
Write 0 to the array element specified by counter ctr1 in PARMADDR. Such processing is performed while changing the value of the counter ctr1 from 1 to n, and when the value of the counter ctr1 exceeds n, the "saved or not saved flag" in the common area is turned on.

If there is no parameter address unchanged indication in the parameter packet area ppa, the parameter is extracted. The parameter extraction process is performed as follows. First, set the value of counter ctr2 to 3.
If the bit specified by counter ctr1 in the parameter specification variable is on, the parameter
The data at the address specified by counter ctr2 in the packet area ppa is transferred to the counter in the array PARMPTR.
Write to the array element specified by ctr1 and write the counter
Update ctr2. If the bit specified by counter ctr1 in the parameter specification variable is off,
Writes 0 to the array element specified by counter ctr1 in array PARMPTR. Such processing is performed while changing the value of the counter ctr1 from 1 to n, and when the value of the counter ctr1 exceeds n, the "saved or not saved flag" in the common area is turned off.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the CALL statement with many arguments can be simplified and the parameter packet area can be reduced. It also has the effect of reducing the number of steps required for argument reference at the call destination.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the principle of the present invention, Figure 2 is a diagram explaining the conversion process to a CALL statement, Figure 3 is a diagram explaining parameter specification variables, Figure 4 is a diagram explaining ANS,
Figure 5 shows an example of the translation result of the CALL statement, Figure 6
Figure 7 shows the structure of the called program.
Figure 8 shows the configuration of the common area, Figure 8 explains the parameter retrieval and saving/restore processing, Figure 9 shows the outline of the compiler, Figure 10 shows the outline of the preprocessor, Figure 11 shows the conventional CALL
It is a figure explaining conversion into a sentence. 1... Preprocessor, 2... Processor.

Claims (1)

[Claims] 1. When a calling program notifies a called program of parameters required by the called program, (a) the address of the parameter required by the called program; and (b) one pair for the parameter. 1, the calling program notifies the called program of the address of a parameter specifying variable consisting of a plurality of bits corresponding to a predetermined value indicating parameter specification and other predetermined values indicating parameter omission. calling method. 2 When the calling program notifies the called program of parameters required by the called program, (a) the address of the parameter required by the called program, and (b) a predetermined value that corresponds one-to-one to the parameter. The calling program calls the address of a parameter specification variable consisting of a plurality of bits indicating that the parameter is specified and omitting the parameter with another predetermined value, and a parameter address unchanged bit that indicates that the parameter address is unchanged with a predetermined value. If the called program is notified by the calling program that the parameter address is unchanged, it saves the parameter address to the common area at the first call, and saves the parameter address to the common area at the second and subsequent calls. A program calling method characterized by restoring and referencing parameter addresses.