DE2110311A1 - Status marking of variables - Google Patents

Description

PHN. 475 ?.

Bcaa / EVK,

Dr. Ihcrt Scfc «is
Applicant: Ν.Υ. Philips'GioeiSampenfabneken ^ '' ^U ° ''

File No., PHIi- 4759

Registration before March 6, 1971

Status marking of variables.

The invention relates to a method for marking status a variable, which is available in the memory of a computer atema and which can be called up during a process. With the status a variable is meant here e.g. Variable is known, unknown, etc.

The best-known computer languages (Algol '60, Fortran ...) and carcassing and machine languages are algorithmiaoh. The languages convey a series of rules according to which the output variables η are derived from the input variables. In the usual technical and mathematical description, however, much more use is made of relationships and equations than of algorithms geeohxiebesi, first "an algorithm that _{derives y from S 1} , X ₂ ··· £, -and secondly the strict requirement"

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that a known y must become invalid as soon as a dex input parametex χ .., x “... χ is changed. As a result, the programmer is obliged to choose the structure of his program in such a way that the mentioned requirement is always met. If this does not happen, the program would, when the variable y is called again, with the previously determined y value, which is now the wrong value _{due to a change in one or more elements X 1} , X _{2 ... χ,} continue to repent. On the other hand, the logger must ensure that if a variable y that can be calculated with the help of another program is requested in the course of a program, this variable y is also available. If this is not the case or is only partially the case (ie only an approximation to the y-value has only been found), reading the content (A (y)) of an address A requested by the program, where the program has the y -Value expected, produce an incorrect or only approximate y-value.

The purpose of the invention is «the programmer of the to get rid of the programming complications mentioned above Objective can be achieved in a technical way. The method for the status marking of a variable is characterized according to the invention in that in the word at the address of the variable in the memory or in a word of the memory from where if the address dex variable is referenced directly or indirectly, a Maikiexungsfeld is reserved in which the statue of the variable is markierbaa, and wherein the status marking duroh the computing maeohizie by means of recognition of the achieved by the variable Status takes place, and being on call dex variable during of a Fseseiaes dex process depending on that status

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can be influenced. This means that in the adding machine technical precautions are taken in the sense of a word format, namely in such a way that there is a space for the mentioned marking field and that a recognition of the by the Variables reached status and an influence on the process in the calculating machine depending on the status of the call of the variable take place through the program. With this method or this Reohner system according to the invention it is possible to access a variable y at an arbitrary point in the computer program. It is always ensured that at address A, where y is expected or from where if the address of y is referenced directly or indirectly, it indicates the status of the variable y. So this can be that y is done, in which case the program can continue, but y can also be unknown or even indeterminable. The program must then be interrupted. Is the Variable y has only been approximated, a decision can be made as to whether the referring program must be continued or interrupted, for example to ( to wait until a parallel process has found a sufficiently precise approximation to y. However, it is also possible that the computer system is still calculating on the variable, so that Program that needs y has to wait. A number of statuses of a variable are also conceivable that can be marked

In the case of an organization in a computer system (for example, with block structure programs) in which memory exibeitx trees are reserved for groups of so-called local variables, it is advantageous that in the method according to the invention in a workroom odex in a word, from where directly odex

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if the work space is indirectly referenced, a space is reserved for a keyword in which the marking fields of the variables present in the workspace are collected. This makes it possible, with just one logical operation on the key word, to readjust the marking code for all variables in the workspace at the same time, i.e. on the respective keep up to date. In such a case, this saves calling, reading, changing and re-entering each variable with their checkbox

There are many possible status options for a variable. Eb is of practical use in dividing these possibilities into, for example, two groups, e.g. a main group of status, under which the possibly familiarity of a variable falls, and a subgroup, under which all sorts of other possibilities, such as approximately known, etc. fall. Another method according to the invention is therefore also characterized in that that the possible statuses of a variable in a workspace are divided into two groups, with one possible status being the first Group in a marking field in the key word belonging to a workspace and a possible status of the second group can be marked in a marking field belonging to a variable. This distribution in groups and the marking in the keyword and in the checkbox of a variable prevent the keywords from becoming too large. Especially in the case It is that a keyword is included in a word from which a direct or indirect reference is made to a workspace It is important that the keyword does not have too much space, for example a number, with regard to the speed of reference occupied by memory words.

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A reunion system in which the above-mentioned procedure is durohfUhrbar is characterized according to the invention, that command line «η are available with which a recognized The status of a variable can be entered in the marking field for the variable, and that further command lines are available, which represent the status of a variable from their checkbox when the variable is called.

Implementation examples of the invention are in the drawings and are explained in more detail below. It shows J

1 shows a computer system according to the invention for performing the method according to the invention,

FIG. 2 shows a possible program structure, FIG. 5 shows a status marking on the access path of a Variable,

4 shows a status marking of a number of variables of a work space in a keyword,

Fig. 5, 6 and 7 examples of a sole keyword in one Word on the access path to variables in a workspace,

8 shows the distribution of the status of a variable over a Checkbox of the variable and a keyword,

9 shows a somewhat different method for arranging and Recognition of a status marker in the marker fields of variables.

The computer system contains a memory M with an input register IR, an output register UR (also shown again in dashed lines with UR ¹ ) and an address register AR. The Reohner system also has a central processor CP. To the

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The command lines W and R and a decoding arrangement DI are used to carry out the method according to the invention. The one in that Memory N available variables y and ζ at the addresses Ao and A1 have the marking fields FIo and PH. The status of the variables can be marked in the FIo and PH marking fields.

The mode of operation of the wire " ¹ system is explained using a program structure shown in FIG.

In Fig. 2, a block structure program is in schematic form Way presented. Py and Pz are the subsidiary blocks of a block Po. As an example, let us assume «that Fz is used to create a variable ζ which depends on the variable y. The draft may also be such that the fact that Pz and Py IJebenblöoke of Po means that y and ζ are local auxiliary variables of Po and thus a working space of Po, i.e. a memory part assigned to the program block Po, anghoreri. If the program Po becomes active, it is assigned a work space PWo in the memory M (see FIG. 1). The variables y and ζ have their own place in the work space PWo at the respective addresses Ao and A1, respectively. While the variables of the central processor storage production takes care of For example, the program Po itself ensures that the command lines W the status a priori unknown (apu) is marked in the marking fields of the variables. With the computer I still have to started so that this status apu will actually be applicable to the variable. A command line W leads the Address Ai from a variable to the address register AR, while another command line W has the status apu in the input register Introduces IR. This status apu is then shown in the marking field FIi of the adroasiartan word Ai entered.

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Wild while implementing a program When the variable is called, the address of the variable is supplied to the address register AR with the aid of a command line R, which The content is read and appears in the output register UR. The variable itself can be transmitted to the central processor will. The marking field of the variable reaches the mentioned decoding arrangement DI. The marking field Fl is decoded in a decoder Fd. There are all sorts of statuses for one Variable conceivable. Examples are ι a program calculates one Variable: busy status "bu". A variable can be given a "partly known" status "ua" in the course of a program. at a scalar quantity this means "approximately known". At a Collection of solutions (array) means that a number of elements are known. The rest of them are unknown, in treatment, etc. Another possibility is that a requested variable is effectively incalculable or proves to be incalculable turns out because the calculation does not converge or because an import date is not available or cannot be calculated etc. This is a status uh (unknown and hopeless). Of course ^

a variable can be known "k" in a moment. All of this Status (there can be nooh more) can be recognized by their own code. The code of a duroh reached a variable Status is in the corresponding marking field and it is introduced into it with the help of the command lines V mentioned above been. The decoding of a marking field Fl in the decoder Depending on the statue, Fd produces a signal at one of the outputs • pu, bu, ua, uh or k. If the status of the variable y is "k", so y is known and the variable y (which is repeated here

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in the right part of the register UR ¹ ateht) can be used in the program Pz for the calculation of ζ. This is reported to the central processor via the instruction k. In this example, an interruption signal "int" occurs for the other possible statuses via the OR puncture element OR. This interrupts the program Pz via the command line int. It is also possible that if a signal occurs at the output or on the command line, among other things, no interruption is necessary, but that the program Pz can be continued with the approximate y-value.

If the organization is such that an interruption takes place for every status except the "k" (known) status, so can the DI arrangement consists exclusively of an OR puncture element exist. If then, for example, the "k" status is denoted by 000 is and the other statuses with at least a one in the code, then there is already an uniqueness. One command line k and a command line int transfer the status to the CP. Furthermore, it is of course possible with the status code, for example ijk, where i, j, k ■ 0 or 1 itself, without decoding in Fd continue to work. The command lines are then called lines the code bits from the register UR to the central processor CP regard.

When running a program, the status will be. change the variable. These changes will be on hand dee programs appointed in the central processor CP, and it If this is permitted, a modified statue is displayed with the help of the command lines W in the corresponding marking field marked. It should be obvious that a status of the variable z,

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which, as I said, also depends on the variable y, not can be changed without further ado. This is only possible when the variable y is known (and no more changes to it it is made).

In the example with the program Po with the sub-blocks Py and Pz, the task in the program Pz is y to read the status of variable y by decoding of the check box FIo checked by y. If the status of y is "k", the program Pz is continued without interruption. If the status of y is "bu", i.e. y is under treatment, then ™

the Py program has already been started on another occasion. (This assumes that Py and Pz can be in execution at the same time, which is possible, for example, if Py and Pz are entered as separate processes. In a computing machine with more than one central processor, Py and Pz can be active at the same time, but also if only one central processor is available, both can be in a meaningful way in the implementation, for example if one of the two programs is started because the other is on i

Input or output must wait). In this case of the status "bu" of y, the program Pz is interrupted. Pz gets to a Waiting list of programs all waiting for y. If the variable y has the status "apu" (unknown), Pz is also interrupted and the system must give an order to start the program Py.

It is important to note that a status marker like the one above is not just in the word at an address A can be present, but that the marker

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can also be made in an earlier word on the access path to the variable. In Fig, J this is given with an example. Suppose a program P ¹ calls a variable y found at address A. Ea gives an access path that must be used to get to that address A. Assume that the path runs in a known manner, practicing the words at the addresses Α · ( _ν ), A "(y) and A '" (y) to A (y). In the program P ¹ , for example, an instruction with the operation code OPC is found at the address A "(y), and also an address part in which a reference address A" (y) is located. The OPC is inserted into an OPCR register (not shown) and the address A "(y) is selected. The word at this address A" (y) reaches the output register UR, here designated UR ". This word on the access path after y contains the marking field Fly. The marking code in this field Ply goes to the decoding arrangement DI, where the status of the variable y is recognized. On the basis of the status it can then be decided whether the route via the path to the variable y at address A (y) should be continued or not. If the status indicates that the variable y is, for example, unknown "apu", an interruption will follow and no further memory accesses to A (y) will take place FSlIe, in which the variable y is not yet suitable for the program P ¹ or is not yet available.

If the status does not cause an interrupt, then all of the one in the word at address A becomes "(y) Address A "'(y) is selected and the content of the word at the Address A "'(y), namely the address A (y), the variable y at this

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Address A (y) read out.

4 shows how it is possible to work with the advantage of a so-called key word in which the marking codes of a number of variables present in a memory work space are collected. In this FIG. 4, a working space in the memory M is indicated with PW. This work space has a base address BW with respect to which the words in the work space are to be addressed with relative addresses g1, g2. Those respective vari- are μ ble yi, yi and yk to find the relative addresses g1, g2, g3 here. At the word position of the base address BW there is a keyword KW, in which the status of the variables of the working space PW is noted. For this, the marking fields FIi, FIj and FIk for the variables yi, yj and yk are available in the word KW. If a status change occurs for one or more variables, this can simply be recorded in KW by inserting the new marking codes into the relevant marking fields of the keyword KW, which has meanwhile been addressed, via the storage register IR (and thus the old field contents are overwritten). This saves many {

Accesses because the changes do not take place per variable to need. When calling a variable e.g. yj from room PW, the following can take place. The address of yj is a combination from BW, the workspace base address, and g2, the relative address of yj in the space. The KW word can only be used with the BW address in the UR register. The marking fields FIi, FIj and FIk can then, for example, in a separate Register R can be used at positions g1, g2, g3. If yj is addressed by BW + g2, then either first or at the same time

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Time the check box Pl.j to pi? Throw in R displayed so that the status of yj can be determined in the decoding arrangement DI. A list, for example a collection of roots of a Equation, can include a workspace. With just one marking code in a marker field in the aforementioned key valley the statue of such a list can be characterized.

In Pig. 5 shows how exn keyword KVB1 included in a word on the access path to workspace B1 is. B1 contains the variables y1 and y2. At an address b1 there is a word that contains the basic acbwBse B1 of the work area B1. In order to get to B1, the word at address b1 is first read out. In that word here is Pig's. 4th mentioned key word KW, here KWB1, added, ao that before dam already addressing the status of the variables y1 and y2 in the work space B1, noted in the marking fields Ply1 and Fly2 from KWP1, are known. This is of great advantage in the Cases in which a workspace is, for example, in a background memory housed, but the word is present at address b1 itself in the main memory of the calculating machine. It it is therefore not necessary to first disconnect work space B1 the background memory in order to be able to determine or change the status of a variable present in it. The happier Mentioned type of status marking in one outside the work area The reference word used to refer to a workspace can appear in many forms in a Rachner system. The following will another example given.

In Fig. 6, each work space Ao, A1, B1 is a so-called Display cell at the respective addresses ao, al and b1 assigned. Such a display cell firstly contains the basic

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.adresae of the workspace to which the cell is assigned. The display cell at the address a1 thus contains the base address A1 of the work space A1 etc. Secondly, a display cell contains an address of a display cell belonging to a work space which is one level higher on a path to the root of a tree in a block structure program. Here, for example, the display cell at address al has an address ao of the display cell belonging to work space Ao. The same applies to the display cells at the addresses b1 with back reference to al and ao with referral to a Adresae 0. The other \ aspects of display cells for the invention described here is not important. It is essential here that the display cells not only have the base address of the workspace to which they are assigned, but also the marking fields of the variables present in the workspaces. For example, the display cell at the address al has the marking fields Ply1 and Fly2 of the variables y1 and y2 of the work space A1.

Other types of addressing in a reunion system,

such as the pagina system, with a status :

marking to be expanded according to the invention. A key word can thus be included in a word in a pagina table, which table specifies the pagina on which the workspace is located: Working space Wp. Is available. In the word, the statue of the variable in WP can be noted in the check boxes FIs (keyword from WP).

In Fig. Θ is shown how a distribution of the marking the status options of a variable in a marking

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field of the variable and represented in a keyword can be. D is a working space with the variables d1, d2, d3. The marking code parts r1, r2, r3 are included in the marking fields FId1, FId2 and FId3. In a keyword KW the marking codes are provided in part · f1, f2. and f3. Venn the Marking codes of all variables of a work area in one Keyword collected, this keyword may become too large for practical use. It's not necessary, that the full tag code of each variable in the The key word. The transition from the statue is unknown "apu" Ober in treatment "bu" and approximately known "ua" after known "k" or indeterminable "ub" etc., finds for each variable instead of separately, so that it is not an obstacle that the marking code of each variable is added separately for these transitions must become. A transition from one of the statuses "bu", "ua", "k", "uh" of the variables of a workspace after "apu" is not passed through the variables themselves determined, but by changing one or more variables on which these mentioned variables depend. It is then advantageous that the marking codes of all variables are changed to the "apu" status at the same time can be. This is possible because the status options are divided into two groups. Contains a main group for example the status marking for "apu" or "apu", where in the subgroup the other status options {only for the If "apu" is given in the main group, this makes sense) are marked. With regard to a above, then ee is practical, the marking for "apu" or "apu" for the variables

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of a work space in a keyword for this work space to undertake. The other status options can then individually 'marked in the marking field of each variable.

In Fig. 8, the main groups of "apu" or "apu" indicating statuses of the variables d1, d2 and d3 in the marking fields f 1, f2 and f3 of the keyword KW added. Here·*· with the "apu" status of all variables can be set simultaneously without each variable having to be selected, etc. For the subgroup of the statue, as mentioned above, it is not difficult to call the variables separately. The subgroup Each variable is then also as marking code r1, r2 and r3 in the respective marking fields Fld1, Fld2 and Fld3 respective variables d1, d2 and d3 were added.

The here mentioned keyword KW of the workspace D can of course also be present outside of the working space D, as mentioned, for example, under FIGS. 5, 6 and 7.

In FIG. 9 it is shown that the arrangement and recognition of the status of variables can also take place in a manner that is somewhat different from that described above. It is assumed here that the memory in which a work space D is accommodated can receive or output information in two ways, namely primarily in the normal way with the input register IR and the output register UR, as has always been mentioned above . Here, a memory word (for example a variable d1 with the marking field Fld1) can be selected as a whole from the address register AR and thus entered or read out. Secondly, it is possible to "cross" out- ZmMhIBTi _9, for example, from the register IR as an address register, ie the same bit position is selected from each word,

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in which case something of each word can be entered at that bit position or read out from it at the same time. In Fig. 9 ie * with ER an extra register is shown in which the selected bit of each word appears when reading out from the memory, or from where the bits can be written to the memory. The checkboxes Pld1, Pld2 ... of the variables d1, d2 ... are normally included in the word of the variable. At the bit positions f1, f2, ... of the respective marking fields Pld1 is for example a bit that indicates whether the status of the relevant variable is known "apu" or unknown "apu". With the one mentioned Cross-selection can then be recognized for all variables at the same time, their status apu or apu in the register ER. The command line apu, apu forwards this status to the central processor. The other way around can be when creating a new workspace directly via the command line apu, apu, the status "apu" for all variables via the register ER at the bit positions f1, f2 ... be marked. As far as the application is concerned, the whole is the same So the key word configuration mentioned earlier. The bit positions r1, r2 ... in the marking fields FId1, FId2, ... are still bidding Place to mark multiple statuses as "apu" and "apu" alone too can.

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Claims (1)

-H- PKN 4759. PATENT CLAIMS : (2 J method for the status marking of a variable which is present in a memory of a computer system and can be called during a process, characterized in that in the word at the address of the variable in the memory or in a word of the memory, from where directly or the address of the variable is indirectly referenced, a marking field is reserved in which the status of the variable can be marked, the status marking by the calculating machine taking place by recognizing the status reached by ™ the variable and where, when the variable is called during a process, the process can be influenced depending on this status. 2. The method according to claim 1, wherein a number of variables are present in a memory work space, characterized in that in a word of the work space or in a word from which reference is made directly or indirectly to the work space of the variable, a space for a keyword is reserved, in which the marking fields for the status marking of the variables present in the work λ space are collected. 3. The method according to claims 1 and 2, characterized in that that the possible statuses of the variables in a workspace are divided into two groups, one possible status being the first Group in a marking field in the special word belonging to a work space and a possible statue of the second group can be masked in a marking field belonging to a variable, lechnejiiyetem to carry out the proceedings naoh Anunjjuoh 1 or 2 * thereby eekamsiseiohnet »dae · command lines 109843 / 1S8S - it - ^Ό ΗΝ. 475% are present with which ain recognized status of a variable can be entered in the marking field for the variable, and that further command lines are available that indicate the status a variable from its marking form when the variable is called represent. 3/1586