AUXILIARY PROGRAMS FOR THE “MINSK-1” COMPUTER FOR AUTOMATING TASK DEBUGGING

N. S. GOLOSOV, O. K. GORDEEV

(Presented by the scientific seminar of the TPI computing laboratory)

Experience in programming tasks for computers has shown that program debugging often constitutes one of the labor-intensive stages in solving tasks.

Often, in the course of a program’s operation, it is necessary to obtain information about the logical and computational parts of the program being debugged. In this, invaluable assistance is provided by a number of debugging programs that automate the technical part of the programmer’s labor.

Comprehensive Debugging Program (KOP)

The program is intended for debugging programs that operate with numbers represented in floating-point form and that use the interpreting system UIS [1].

The debugging program makes it possible to execute, according to a specified instruction, any segment of the program being debugged, after first carrying out certain auxiliary operations.

The information for the debugging program consists of standard lines:

1) lines specifying a segment;
2) lines of transfers;
3) lines specifying a step and a counter;
4) output lines;
5) end line.

a) Line specifying a segment

The information line has the form:

\[ \begin{array}{ccccc} \text{KOP} & I & II \\ & \text{address} & \text{address,} \\ \pm & 07 & A_{\text{н}} & A_{\text{к}} \end{array} \]

where \(A_{\text{н}}\) and \(A_{\text{к}}\) are the addresses of the beginning and end of the segment of the program being debugged. With the sign “−” in KOP, for such a line during debugging, information about the logic of the program will be output; it is output in the form of linear segments (rays), and the number of such segments if they are repeated several times in succession (in a loop) (see Example 1). With the sign “+” in KOP, the logic is not output for the information line specifying a segment.

b) Transfer-instruction lines

The information on transfers consists of two lines:

which specify the type of transfer and the place in the program being debugged to which codes or numbers must be transferred. The sign “+” in the COP of the first line indicates that a preliminary conversion from the decimal to the binary system of notation must be performed; the sign “−” indicates that such conversion is not necessary.

$A_{\text{н}}$ and $A_{\text{к}}$ are the beginning and end of the cells into which codes or numbers must be transferred. $a_{\text{н}}$ is the address of the beginning of the array in which the numbers or codes are located (see Example 2).

c) Step and counter line

The information line has the form

where $\Ш$ is the step by which readdressing will be carried out in the section of the program specified by the section-assignment line. $C$ is the counter [1]. If the step and counter need not be changed, the line has the form

$$ +00\quad 0000\quad 0000. $$

d) Output line

According to a line of the form

codes or numbers are output to print. The sign “+” indicates decimal output, “−” octal output. $A_{\text{н}}$ and $A_{\text{к}}$ are the initial and final addresses of the cells that must be output to print. In decimal output, the binary contents of the cells $A_{\text{н}}—A_{\text{к}}$ are preserved.

e) End line

The end line must have the form

At this line the debugging program finishes its work.

Information lines of types 1–4 form a block. Any number of such blocks may be specified consecutively. One line of type 5 must be specified at the end of all the blocks (see Example 2). All information appearing in the block before the step-and-counter assignment line is implemented before the operation of the program section (line of type 1). Lines of the fourth type, if they follow lines of the third type, will output information only after the operation of the program section specified in this block.

The program provides for enabled octal printing, while enabling and disabling decimal printing is blocked by a stop.

The comprehensive debugging program occupies 205 cells. Before calling it, it is necessary to place, in cell 1000 at the second address, the number of the cell from which the information begins. To begin debugging, control must be transferred to cell 1000 of the COP. In the event of an emergency stop or cycling in the program being debugged, it is possible to output the information provided for the section. To do this, control should be transferred to cell 1126.

Program for Automatic Address Reworking

In the course of programming and debugging, the need arises to shift, rearrange, or discard individual arrays of commands or numbers from the program being debugged. Carrying out such processes manually is laborious mechanical work and is not guaranteed against errors, since the entire program being debugged must be reworked anew.

The program for automatic address reworking (PAPA) automatically, according to instructions, rearranges program and numerical arrays in memory. In accordance with this movement, PAPA reworks in the program the addresses belonging to the arrays being moved, composes a new program in the RAM zone, calls it, and outputs it to print.

The information for PAPA is prepared in encoded form (see Appendix 1) from lines of three types: information \(A\), \(B\), \(C\), and separators.

Information \(A\) consists of lines specifying the sections of the program where the addresses of the shifted arrays occur. These lines are written as follows:

\[ \begin{aligned} A+0)&\ --\ A_{\mathrm{n}}^{1}\quad A_{\mathrm{k}}^{1}\quad A_{\mathrm{p}},\\ A+1)&\ --\ A_{\mathrm{n}}^{2}\quad A_{\mathrm{k}}^{2}\quad A_{\mathrm{p}},\\ &\qquad \cdot\quad \cdot\quad \cdot\quad \cdot\\ &\qquad \cdot\quad \cdot\quad \cdot\quad \cdot\\ A+k)&\ --\ A_{\mathrm{n}}^{k+1}\ldots A_{\mathrm{k}}^{k+1}\ldots A_{\mathrm{p}},\\ A+k+1)&\ +\ 00\ 0000\ 0000, \end{aligned} \]

where \(A_{\mathrm{n}}, A_{\mathrm{k}}\) are the initial and final addresses of the \(k\)-th program array in the RAM, not containing constants; \(A_{\mathrm{p}}=0007\) is the flag; in \(A+k+1\) is the separator cell (zero).

Information \(B\) follows information \(A\) immediately after the separator and consists of lines for assembling the program in the RAM (lines with “\(+\)”) and reading from the RAM (lines with “\(-\)”) in the executed sequence:

\[ \begin{aligned} B+0)&\ A_{\mathrm{n}}^{1}\ldots A_{\mathrm{k}}^{1}\ldots A_{\mathrm{m}}\\ B+1)&\ A_{\mathrm{n}}^{2}\quad A_{\mathrm{k}}^{2}\quad A_{\mathrm{m}}^{2}\\ &\qquad \cdot\quad \cdot\quad \cdot\quad \cdot\quad \cdot\quad \cdot\\ B+k)&\ --\ A_{\mathrm{n}}^{k+1}\ldots A_{\mathrm{k}}^{k+1}\ldots A_{\mathrm{m}}^{k+1}\ldots\\ B+k+1)&\ --\ 00\ 0000\ 0000,\\ B+k+2)&\quad 47\ 0000\ 0000, \end{aligned} \]

where \(A_{\mathrm{n}}, A_{\mathrm{k}}\) are the initial and final addresses of the RAM from which the information is written into the RAM, if the line is “\(+\),” or from which ...

are read if the line is “—”; \(A_m\) is the MZU address from which the exchange begins. The information ends with a delimiter and a command by which PAPA terminates operation, if the command is “stop,” or transfers control to the first address, if the command is \(24\ A,\ 0000\) (it is essential that, for this command, the second address be zero).

Information \(C\) specifies the shifting of arrays located earlier from addresses \(A_n\) through address \(A_k\), with the new beginning \(A_{nn}\):

\[ C+0)\quad A_n^1 \quad A_k^1 \quad A_{nn}^1 \]

\[ C+1)\quad A_n^2 \quad A_k^2 \quad A_{nn}^2 \]

\[ \cdot\quad \cdot\quad \cdot\quad \cdot\quad \cdot \]

\[ C+k)\quad A_n^{k+1}\ \ldots\ A_k^{k+1}\ \ldots\ A_{nn}^{k+1}\ \ldots \]

\[ C+n+1)\quad 24\quad A_0+2\quad 0000. \]

At the end of the \(C\)-information, a command is placed in which \(A_0\) is the address of the beginning of PAPA.

The number of lines of each type is arbitrary, or they may be absent altogether; however, in each type of information the delimiters and service commands must be present.

PAPA begins operation from cell 0100. Before operation begins, in cells 0020 and 0021 the addresses of the beginning of the \(A\)- and \(C\)-information, respectively, must be entered as the first address.

If the machine is operating correctly, PAPA performs all actions without stops. The program checks the exchange with the MZU. If the check sums do not coincide, a stop occurs; the beginning and end of the exchange are issued to register \(A\), and the check sum to \(B\). When the machine is started, the reading of this array is repeated.

The PAPA program is self-summing. To record it correctly in the required zone, the following actions must be performed:

1. Change the write-read constants at the end of the program.
2. Set a stop at address 0156, start from 0141.
3. After the stop, start from 0247.
4. Read from cells 137, 140 (correct recording: stop \(37\ 0000\ 0020\)).

Appendix 1

Example 1. The program begins with cell 0500 and ends with cell 0570. During operation, sections 0500–0520 are repeated five times, 0521–540 once, and 0541–0570 three times.

The following beams will be issued for printing:

Example 2. Suppose it is necessary to debug, in parts, a program occupying cells from 0400 to 0500. The debugging must be performed as follows:

1. Before the program operates, it is necessary to send to cell 0411 the code: \(0411)\ 24\ 0420\ 0000\); send, with conversion to the binary system, into cells 0470–0500 the numbers from cells 0600–0610.

The program must run from 0400 to 450 and issue beams in this section. After the work is performed, it is necessary to print out the section of the program 0400–0460, and also issue working cells 0700–0710 with conversion to the decimal numeral system.

Complex Debugging Program (KOP)

Continuation of the table

Continuation of the table

Continuation of the table

PAPA Program

Continuation of the table

Continuation of the table

1. Execute the program segment 0450–0467 without making any preliminary transfers, but only by changing the step and setting the counter: \(SH = 4\), \(C = 0024\). After executing the segment, print the working cells 0720–0722. End debugging.

The information for such debugging should have the following form:

Appendix 1

The digit grid of the Minsk-1 machine makes it possible to record three addresses in one cell. This record also forms an information line for PAPA.

In each address only \(10_{10}\) binary digits are occupied. By shifting the first address two binary digits to the right, we free \(10_{10}\) binary digits for \(A_n\). The information must be written first in the three-address system and then coded.

References

N. S. Golosov, O. K. Gordeev. Universal Interpreting System (UIS). In the present collection.