WO1983001319A1 - Register allocation apparatus - Google Patents

Register allocation apparatus Download PDF

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Publication number
WO1983001319A1
WO1983001319A1 PCT/GB1981/000212 GB8100212W WO8301319A1 WO 1983001319 A1 WO1983001319 A1 WO 1983001319A1 GB 8100212 W GB8100212 W GB 8100212W WO 8301319 A1 WO8301319 A1 WO 8301319A1
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WO
WIPO (PCT)
Prior art keywords
memory
free
selection
accordance
registers
Prior art date
Application number
PCT/GB1981/000212
Other languages
French (fr)
Inventor
Corporation Burroughs
Machines Limited Burroughs
Dongsung Robert Kim
Original Assignee
Burroughs Corp
Burroughs Machines Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Burroughs Corp, Burroughs Machines Ltd filed Critical Burroughs Corp
Priority to BR8109026A priority Critical patent/BR8109026A/en
Priority to PCT/GB1981/000212 priority patent/WO1983001319A1/en
Publication of WO1983001319A1 publication Critical patent/WO1983001319A1/en

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    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06FELECTRIC DIGITAL DATA PROCESSING
    • G06F9/00Arrangements for program control, e.g. control units
    • G06F9/06Arrangements for program control, e.g. control units using stored programs, i.e. using an internal store of processing equipment to receive or retain programs
    • G06F9/46Multiprogramming arrangements
    • G06F9/52Program synchronisation; Mutual exclusion, e.g. by means of semaphores

Definitions

  • This invention relates to means and methods for allocating resources in an electronic digital data processing system.
  • a primary object of the present invention is to provide particularly useful and advantageous apparatus for allocating resources in a data processing system.
  • the principles of the invention are applied to the function of allocating registers ' required for use by a plurality of tasks being concurrently performed by a data processing system.
  • a data processing system typically, the system
  • ⁇ LJ ⁇ Q ⁇ aa a ⁇ rr Lrr i provides a predetermined number of registers which are allocatable for use by a plurality of active tasks.
  • an updatable list of free and assigned registers is maintained and, as each task is activated, specially provided register selection apparatus responsive to this list selects a predetermined number of free registers for assignment to the task. If insufficient free registers are available for use by a newly activated task, it is signalled to remain in a "hold" state.
  • the register selection apparatus includes a plurality of specially mapped memories to which respective portions of the updatable list of free and assigned registers are applied as memory addresses for reading out selected memory words.
  • These selected memory words identify available free registers and also provide appropriate logic for controlling a plurality of multiplexers to which the selected memory words are applied.
  • These multiplexers operate to select a particular plurality of the available free registers for assignment to each newly activated task where sufficient free registers are available to meet the task's requirements.
  • the sufficiency of free registers for a newly activated task is determined by comparing the number of free registers required by a task with the total number of free registers which the selected memory words indicate are available. If insufficient free registers are available for assignment to a task, the comparator provides a "hold" signal for use in placing the task in a "hold” state.
  • FIG. 1 is a schematic and electrical diagram illustrating a preferred embodiment of the invention.
  • FIG. 2 is a schematic and electrical diagram illustrating details of the FIG. 1 embodiment.
  • FIG. 3 is a series of tables illustrating the operation of the multiplexers in FIG. 2.
  • an allocation register 10 is provided whose states indicate the free and assigned states of a plurality of assignable registers.
  • the allocation register 10 will be assumed to contain sixteen bit storage elements r - r respectively corresponding to the 1 16 assignable registers Rl - R16, wherein a "1" value of a bit storage element is used to indicate that its corresponding register is unavailable for assignment, while a "0" value indicates that the corresponding register is free and thus available for assignment. It will further be assumed by way of example that, at a particular point in time, the sixteen bit elements -C, - * r _ of the allocation register 10 have the 1 16 respective values 0101010001101010 shown in FIG. 1. Thus, register 10 in FIG. 1 indicates that the seven registers R2,
  • R4, R6, R10, Rll, R13 and R15 are free registers.
  • each of these memories 15 and 20 may typically be a PROM (programmable read only memory) .
  • FIG. 1 the construction and operation of the preferred embodiment of FIG. 1 is such that appropriate portions of the selected memory words read out from memories 15 and 20
  • I (in response to the respective addresses provided by the allocation register 10) are applied to a comparator 25 for determining whether a sufficient number of free registers are available for a newly activated task, and are also applied to a plurality of multiplexers 30 for identifying a particular number of free registers available for assignment to a newly activated task based on the current state of the elements r - r of the allocation register 10.
  • FIG. 1 The construction and operation of FIG. 1 will now be considered in more detail with reference to FIG. 2.
  • multiplexers 30 in FIG. 1 are shown in FIG. 2 as comprising the five multiplexers 31 - 35 whose outputs M - M are binary numbers identifying five particular free registers available for assignment to a newly activated task based on the current states of the bit storage elements of the allocation register 10.
  • these five free registers identified by the multiplexer outputs M - M are the five lowest numbered free registers currently available, which, in conformance with the states of the allocation register 10, are registers R2, R4, R6, RIO and Rll.
  • FIG. 2 illustrates examples of the particular selected memory words W-A and W-B read out from memories 15 and 20, respectively, in response to the
  • SUBSTITUTE SHEET f OMPI WH illustrated states of their corresponding portions of the allocation register 10 shown in FIG. 1. It will be understood that, for greater clarity, decimal numbers are used in FIG. 2 to indicate the contents of the various memory word portions; however, these decimal numbers are preferably stored in binary form in memories 15 and 20.
  • W-A from memory 15 provides data relative to registers
  • each memory word contains a number (designated SA for memory word W-A and SB for memory word W— B) indicating the total number of free registers in accordance with the states of the respective " elements of the allocation register 10 in
  • FIG. 1A The next portion of each memory word (designated 1A,
  • 2A, 3A, -4A, 5A ' for memory word W-A and IB, 2B, 3B, 4B, 5B for memory word W-B) identifies (also in accordance with its respective elements of register 10) up to five free registers beginning with the lowest number free register; an "X" indicates that no additional free registers are available besides those indicated and may typically have a "don't care” value such as "0" (since there is no "0" register).
  • SA properly indicates a total of three free registers for W-A
  • SB properly indicates a total of four free registers for W-B.
  • lA, 2A and 3A of memory word W-A respectively identify the three free registers 2, 4 and 6 indicated by elements r. - r_ of register 10, while 4A and 5 are properly 1 o indicated as "X" (don't care) values (since elements r - r
  • OMPI IB, 2B, 3B, 4B of memory word W-B respectively identify the four free registers 10, 11, 13 and 15 indicated by elements r n - r. _ of register 10, while 5B indicates a "don't care" 9 16 value (since elements r - x indicate no other free
  • memory word W-A additionally includes portions designated as m., m , m , m. and m . These portions could alternatively be included with memory word W-B or they could be split up between the two memory words. As indicated in FIG. 2, these m , m , m ,
  • 1 2 3 m and m portions are respectively applied as selection signals to multiplexers Ml, M2, M3, M4 and M5, and different pluralities of portions 1A to 5A and IB to 5B of memory words W-A and W-B are respectively applied as register identification input signals to each of multiplexers Ml - MS.
  • Ml - M5 and the number of bits required for each of - m are dependent on the number of 1A to 5A and IB to 5B input applied to each multiplexer.
  • 1 5 particular pluralities of portions 1A to 5A and IB to 5B to be applied to each of multiplexers Ml - M5 in FIG. 2 is based on obtaining, at the . multiplexer outputs, identifications of a particular group of free registers for assignment to each newly activated task.
  • this particular group of free registers is chosen as the five lowest numbered free registers which, for the exemplary states of the allocation register 10 illustrated in FIG. 1, are registers R2, R4, R6, RIO and Rll as indicated at the multiplexer outputs in FIG. 2.
  • the tables of FIG. 3 set forth the operation of the multiplexers Ml - M5 in response to the respective m - m and 1A to 5A and IB to 5B signals applied thereto (as shown in FIG. 2), whereby the five
  • multiplexer Ml has only the two inputs 1A and IB from memory words W-A and W-B applied thereto so that i ts selection input need only be a single bit. Since 1A of memory word
  • W-A contains a "2" identifying R2 as the lowest number free reg ister , the value of m for word W-A is chosen as a " 0 " to cause the contents o f 1A (which identifies reg ister R2 as a free reg ister) to be selected as the output of mul tiplexer
  • each multiplexer Ml - M5 in the preferred embod iment is chosen so that each multiplexer selects the lowest numbered input of the particular plural ity of 1A - 5A and IB - 5B inputs applied thereto which identifies a free register, with an "A" input being selected ahead of a "B” input .
  • multiplexer M2 has the three inputs 2A, IB and 2B of memory word W-A and W-B applied thereto so that m_ requ ires two b its for selecting among 2A, IB and 2B, as illustrated in the multiplexer M2 table in FIG. 3. Since 2A of memory word W-A contains a "4 " identifying R4 as a free reg ister , for word W-A is chosen as "00" to cause the contents of 2A (which identifies reg ister R4 as a free reg ister) to be selected as the output of multiplexer M2.
  • Multiplexer M3 in FIG. 2 has the four inputs 3A, IB, 2B, 3B from memory words W-A and W-B applied thereto which , l ike m , requires a two bit m input for selection as illustrated in FIG. 3. Since 3A of memory word W-A contains
  • SUBSTITUTE SHEET O a "6" identifying R ⁇ as a free register, m for word W-A is chosen as "00" to cause the contents of 3A (which identifies register R6 as a free register) to be selected as the output of multiplexer M3.
  • Multiplexer M4 in FIG. 2 has the five inputs 4A, IB,
  • the remaining multiplexer M5 in FIG. 2 has the six inputs 5A, IB, 2B, 3B, 4B , 5B from memory words W-A and W-B applied thereto which, like m , requires a three bit m input for selection as illustrated in FIG. 3.
  • the first free register identified by the inputs applied to M5 is indicated by 2B which contains an "11" identifying register Rll as a free register.
  • m is chosen
  • the free register identifications provided at the output of the multiplexers 30 are applied to an update circuit 50 along with the number of free registers required by the task.
  • the update circuit 50 responds to these inputs by providing an output to the allocation register 10 which updates the values of the storage elements r. accordingly.
  • the SA abd SB portions of memory words W-A and W-B contain the to.tal number of free registers indicated by their respective portions of the allocation register 10 in FIG. 1. Accordingly, these SA and SB values are applied to the comparator 25 which also receives an input indicating the number of free registers required by a newly initiated task. The comparator 25 compares the sum of SA and SB with the number of free registers required by the task. If insufficient free registers are available, the comparator 25 produces a HOLD signal which is used to cause the task to wait until sufficient free registers are available.

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  • Software Systems (AREA)
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Abstract

Register selection apparatus which includes a plurality of specially mapped programmable memories each addressed by a respective portion of an updatable allocation register which indicates the free and assigned states of a plurality of registers. The resulting memory words read out from the memories are applied to a plurality of multiplexers for identifying a particular predetermined group of registers as being available for assignment. The memory words also provide signals for use in determining whether a sufficient number of free registers are currently available for assignment.

Description

TITLE
REGISTER ALLOCATION APPARATUS
BACKGROUND OF THE INVENTION
This invention relates to means and methods for allocating resources in an electronic digital data processing system.
As is well known, an important function performed within a data processing system having ulti-programming and/or multiprocessing capabilities is the allocation of the available resources to the various data processing operations being performed. The manner and efficiency of this allocation of resources can have a significant impact on system performance and economy. SUMMARY OF THE PRESENT INVENTION
A primary object of the present invention is to provide particularly useful and advantageous apparatus for allocating resources in a data processing system.
In a preferred embodiment, the principles of the invention are applied to the function of allocating registers' required for use by a plurality of tasks being concurrently performed by a data processing system. Typically, the system
. <LJ Ϊ Qξaaaϊrr Lrr i provides a predetermined number of registers which are allocatable for use by a plurality of active tasks. In the preferred embodiment, an updatable list of free and assigned registers is maintained and, as each task is activated, specially provided register selection apparatus responsive to this list selects a predetermined number of free registers for assignment to the task. If insufficient free registers are available for use by a newly activated task, it is signalled to remain in a "hold" state.
In the preferred embodiment, the register selection apparatus includes a plurality of specially mapped memories to which respective portions of the updatable list of free and assigned registers are applied as memory addresses for reading out selected memory words. These selected memory words identify available free registers and also provide appropriate logic for controlling a plurality of multiplexers to which the selected memory words are applied. These multiplexers operate to select a particular plurality of the available free registers for assignment to each newly activated task where sufficient free registers are available to meet the task's requirements. The sufficiency of free registers for a newly activated task is determined by comparing the number of free registers required by a task with the total number of free registers which the selected memory words indicate are available. If insufficient free registers are available for assignment to a task, the comparator provides a "hold" signal for use in placing the task in a "hold" state.
The combination of the list of free and unassigned registers, the specially mapped memories and the multiplexers, as briefly described above, provide for register allocation in a highly advantageous and economical manner which is well suited for use in a multiprogramming and/or multiprocessing environment. The specific nature of the invention as well as other objects, advantages, features and uses thereof will become apparent from the following detailed description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic and electrical diagram illustrating a preferred embodiment of the invention.
FIG. 2 is a schematic and electrical diagram illustrating details of the FIG. 1 embodiment.
FIG. 3 is a series of tables illustrating the operation of the multiplexers in FIG. 2.
SUBSTITUTE SHEET
OMPI ""WHIPOO DETAILED DESCRIPTION OF THE INVENTION
Like numerals refer to like elements throughout the drawings.
Referring to FIG. 1, illustrated therein is a preferred embodiment of register allocation apparatus in accordance with the invention. As shown, an allocation register 10 is provided whose states indicate the free and assigned states of a plurality of assignable registers.
For the purposes of this description and by way of example, it will be assumed that there are sixteen registers Rl to
R16 available for assignment. Accordingly, the allocation register 10 will be assumed to contain sixteen bit storage elements r - r respectively corresponding to the 1 16 assignable registers Rl - R16, wherein a "1" value of a bit storage element is used to indicate that its corresponding register is unavailable for assignment, while a "0" value indicates that the corresponding register is free and thus available for assignment. It will further be assumed by way of example that, at a particular point in time, the sixteen bit elements -C, - *r _ of the allocation register 10 have the 1 16 respective values 0101010001101010 shown in FIG. 1. Thus, register 10 in FIG. 1 indicates that the seven registers R2,
R4, R6, R10, Rll, R13 and R15 are free registers.
As indicated in FIG. 1, the first eight bit storage elements r — r of the .allocation register 10 .are applied
1 8 as an address to a first memory 15 and the second eight bit storage elements r' - r are applied as an address to a second memory 20. Each of these memories 15 and 20 may typically be a PROM (programmable read only memory) .
Generally, the construction and operation of the preferred embodiment of FIG. 1 is such that appropriate portions of the selected memory words read out from memories 15 and 20
Ofc- £_,,_, _ _ a ς , _ £_>_"*_____, I (in response to the respective addresses provided by the allocation register 10) are applied to a comparator 25 for determining whether a sufficient number of free registers are available for a newly activated task, and are also applied to a plurality of multiplexers 30 for identifying a particular number of free registers available for assignment to a newly activated task based on the current state of the elements r - r of the allocation register 10.
1 16
These free register identifications and a corresponding task identification number are stored in a register mapper 40 so that, when the register mapper 40 is accessed during task execution, these register identifications are read out and 'applied to a register file 45 for accessing the identified registers.
The construction and operation of FIG. 1 will now be considered in more detail with reference to FIG. 2. For this purpose, and by way of example, it will be assumed that each task requires a maximum of five free registers. Accordingly, multiplexers 30 in FIG. 1 are shown in FIG. 2 as comprising the five multiplexers 31 - 35 whose outputs M - M are binary numbers identifying five particular free registers available for assignment to a newly activated task based on the current states of the bit storage elements of the allocation register 10. For the illustrated embodiment of FIG. 2, it is assumed that these five free registers identified by the multiplexer outputs M - M are the five lowest numbered free registers currently available, which, in conformance with the states of the allocation register 10, are registers R2, R4, R6, RIO and Rll.
In order to permit the mapping of memories 15 and 20 to be readily understood, FIG. 2 illustrates examples of the particular selected memory words W-A and W-B read out from memories 15 and 20, respectively, in response to the
SUBSTITUTE SHEET f OMPI WH illustrated states of their corresponding portions of the allocation register 10 shown in FIG. 1. It will be understood that, for greater clarity, decimal numbers are used in FIG. 2 to indicate the contents of the various memory word portions; however, these decimal numbers are preferably stored in binary form in memories 15 and 20.
It will also be understood that the selected memory word
W-A from memory 15 provides data relative to registers
Rl — R8 (since memory 15 is addressed by elements r - r of
1 8 register 10), while the memory word W-B from memory 20 provides data relative to registers R9 - R16 (since memory 20 is addressed by elements r - r of register 10). Thus, proceeding from left to right, the left-most portion of each memory word contains a number (designated SA for memory word W-A and SB for memory word W— B) indicating the total number of free registers in accordance with the states of the respective "elements of the allocation register 10 in
FIG. 1. The next portion of each memory word (designated 1A,
2A, 3A, -4A, 5A'for memory word W-A and IB, 2B, 3B, 4B, 5B for memory word W-B) identifies (also in accordance with its respective elements of register 10) up to five free registers beginning with the lowest number free register; an "X" indicates that no additional free registers are available besides those indicated and may typically have a "don't care" value such as "0" (since there is no "0" register).
Thus, for memory word W-A in FIG. 2, SA properly indicates a total of three free registers for W-A, and SB properly indicates a total of four free registers for W-B.
Also, lA, 2A and 3A of memory word W-A respectively identify the three free registers 2, 4 and 6 indicated by elements r. - r_ of register 10, while 4A and 5 are properly 1 o indicated as "X" (don't care) values (since elements r - r
1 8 indicate no other free registers) . In a similar manner,
OMPI IB, 2B, 3B, 4B of memory word W-B respectively identify the four free registers 10, 11, 13 and 15 indicated by elements rn - r. _ of register 10, while 5B indicates a "don't care" 9 16 value (since elements r - x indicate no other free
9 16 registers) .
It will be noted in FIG. 2 that memory word W-A additionally includes portions designated as m., m , m , m. and m . These portions could alternatively be included with memory word W-B or they could be split up between the two memory words. As indicated in FIG. 2, these m , m , m ,
1 2 3 m and m portions are respectively applied as selection signals to multiplexers Ml, M2, M3, M4 and M5, and different pluralities of portions 1A to 5A and IB to 5B of memory words W-A and W-B are respectively applied as register identification input signals to each of multiplexers Ml - MS.
As is to be expected, the size of each of the multiplexers
Ml - M5 and the number of bits required for each of - m are dependent on the number of 1A to 5A and IB to 5B input applied to each multiplexer.
The choice of the values of m. - m_ and the
1 5 particular pluralities of portions 1A to 5A and IB to 5B to be applied to each of multiplexers Ml - M5 in FIG. 2 is based on obtaining, at the. multiplexer outputs, identifications of a particular group of free registers for assignment to each newly activated task. In the preferred embo iment, this particular group of free registers is chosen as the five lowest numbered free registers which, for the exemplary states of the allocation register 10 illustrated in FIG. 1, are registers R2, R4, R6, RIO and Rll as indicated at the multiplexer outputs in FIG. 2. The tables of FIG. 3 set forth the operation of the multiplexers Ml - M5 in response to the respective m - m and 1A to 5A and IB to 5B signals applied thereto (as shown in FIG. 2), whereby the five
SUBSTITUTE SHEET O PI - lowest numbered free reg isters are identified at the multiplexer outputs .
The tables of FIG. 3 will now be considered in more detail with specific reference to the exemplary values of the memory word s W-A and W-B illustrated in FIG. 2.
It will be understood from FIGS . 2 and 3 that multiplexer Ml has only the two inputs 1A and IB from memory words W-A and W-B applied thereto so that i ts selection input need only be a single bit. Since 1A of memory word
W-A contains a "2" identifying R2 as the lowest number free reg ister , the value of m for word W-A is chosen as a " 0 " to cause the contents o f 1A ( which identifies reg ister R2 as a free reg ister) to be selected as the output of mul tiplexer
Ml. In this regard, it is to be noted that the respective m 1, , π 2, m 3_ , m 4_ , m 5_ inputs for the multiplexers Ml - M5 in the preferred embod iment are chosen so that each multiplexer selects the lowest numbered input of the particular plural ity of 1A - 5A and IB - 5B inputs applied thereto which identifies a free register, with an "A" input being selected ahead of a "B" input .
As ind icated in FIG. 2 multiplexer M2 has the three inputs 2A, IB and 2B of memory word W-A and W-B applied thereto so that m_ requ ires two b its for selecting among 2A, IB and 2B, as illustrated in the multiplexer M2 table in FIG. 3. Since 2A of memory word W-A contains a "4 " identifying R4 as a free reg ister , for word W-A is chosen as "00" to cause the contents of 2A (which identifies reg ister R4 as a free reg ister) to be selected as the output of multiplexer M2.
Multiplexer M3 in FIG. 2 has the four inputs 3A, IB, 2B, 3B from memory words W-A and W-B applied thereto which , l ike m , requires a two bit m input for selection as illustrated in FIG. 3. Since 3A of memory word W-A contains
SUBSTITUTE SHEET
Figure imgf000010_0001
O a "6" identifying Rβ as a free register, m for word W-A is chosen as "00" to cause the contents of 3A (which identifies register R6 as a free register) to be selected as the output of multiplexer M3.
Multiplexer M4 in FIG. 2 has the five inputs 4A, IB,
2B, 3B, 4B from memory words W-A and W-B applied thereto which requires a three bit m4 input for selection as illustrated in FIG. 3. The first free register identified by the inputs applied to M4 is indicated by IB which contains a "10" identifying register. R10 as a free register. Thus, in accordance with FIG. 3, πi is chosen as "001" to cause the
4 contents of IB to be selected as the output of multiplexer M4.
The remaining multiplexer M5 in FIG. 2 has the six inputs 5A, IB, 2B, 3B, 4B , 5B from memory words W-A and W-B applied thereto which, like m , requires a three bit m input for selection as illustrated in FIG. 3. The first free register identified by the inputs applied to M5 is indicated by 2B which contains an "11" identifying register Rll as a free register. Thus, in accordance with FIG. 3, m is chosen
5 as 010 (which is "2" in decimal) to cause the contents of 2B to be selected as the output of multiplexer M5.
Referring back to FIG. 1, it will be seen that the free register identifications provided at the output of the multiplexers 30 are applied to an update circuit 50 along with the number of free registers required by the task.
The update circuit 50 responds to these inputs by providing an output to the allocation register 10 which updates the values of the storage elements r. accordingly.
16
Having described how selection of the five lowest numbered free registers is accomplished in the preferred embodiment illustrated in FIGS. 1-3, it will next be considered how the situation is handled by the preferred embodiment when there are insufficient free registers available for assignment to. a newly activated task.
Figure imgf000011_0001
It will be remembered that the SA abd SB portions of memory words W-A and W-B contain the to.tal number of free registers indicated by their respective portions of the allocation register 10 in FIG. 1. Accordingly, these SA and SB values are applied to the comparator 25 which also receives an input indicating the number of free registers required by a newly initiated task. The comparator 25 compares the sum of SA and SB with the number of free registers required by the task. If insufficient free registers are available, the comparator 25 produces a HOLD signal which is used to cause the task to wait until sufficient free registers are available.
Although the description provided herein has been directed to a particular preferred embodiment, it is to be understood that many modifications and variations in structure, arrangement, components, operations and use are possible without departing from _ the spirit of the invention. The present invention should accordingly be considered as encompassing all such possible modifications and variations coming within the scope of the appended claims.
SUBSTITUTE SHEET OMPI

Claims

- l l - a - a . -What is claimed is:
1. For use in a data processing system, resource allocation apparatus comprising: storage means indicating the free and assigned states of a plurality of resources, said storage means including a plurality of portions, each portion indicating the free and assigned states of a particular predetermined plurality of said resources; a plurality of individually addressable memories, each memory being addressed by a respective one of said portions and being operative in response thereto for providing a corresponding memory output including free resource identifying signals which identify at least a predetermined plurality of the free resources indicated by the applied address, the memory outputs from said memories also including a plurality of selection signals; and a plurality of selection means to v/hich said memory outputs are applied, each selection means receiving particular ones of said register identifying signals and said selection signals and being operative in response thereto. so that the outputs of said selection means identify a particular predetermined plurality of the free resources indicated by said storage means.
SUBSTITUTE SHEET
OMPI .
2. * The invention in accordance with claim 1, wherein said selection means comprises a plurality of multiplexers, one for each resource to be identified, wherein each multiplexer receives as a multiplexer input a different predetermined plurality of said free resource identifying signals provided by said memory outputs, and wherein each multiplexer receives as a selection input a respective one or more of said selection signals provided by said memory outputs.
3. The invention in accordance with claim 2, wherein said multiplexers successively receive a greater number of said register identifying signals.
4. The invention in accordance with claim 1, wherein said plurality of resources are a plurality of registers.
5. The invention in accordance with claim 1, wherein each of said memories is a programmable read only memory.
6. The invention in accordance with claim 1, 2, 3 or
4, including updating means responsive to the outputs of said selection means for updating said storage means.
<S5 l -r^rr-"--- ι-~- ~-- c-.f r ---*•- -—••■»
-£tϊRBX
OMPI
7. The .invention in accordance with claim 1, 2 or 3 , wherein each memory stores a plurality of individually addressable memory words, one of which is selected by the applied address for providing the memory output of the memory, wherein each memory word contains resource identifying data identifying at least a predetermined plurality of the free resources indicated by the applied memory address, said resource identifying data corresponding to the register identifying signals in the memory output, and wherein the memory words of at least one memory includes a plurality of selection data' items, one item for each selection means, said selection data items corresponding to said selection signals in the memory output .
8. The invention in accordance with claim 7, wherein said selection data items are chosen in conjunction with the choice of the predetermined plurality of resource identifying signals applied to each selection means so that a predetermined ordered group of free resources are identified at the outputs of said selection means.
9. The invention in accordance with claim 8, wherein said resources are designatable in a particular numerical order, and wherein the choice of said selection data items and the choice of the predetermined plurality of resource identifying signals applied to each selection means are such that the lowest numbered free resources are identified at the outputs of said selection means.
SUBSTITUTE SHEET
OMPI
10. The invention in accordance with claim 1, 2, 3 or 4 , wherein said system operates by performing a plurality of tasks, wherein each task requires the assignment of one or more free resources thereto, and wherein resource mapping means are provided for storing the outputs of said selection means and a corresponding task identification.
11. The invention in accordance with claim 1, 2, 3 or 4, wherein each memory output also includes signals representing the number of free registers indicated by its respective portion of said storage means, and wherein comparison means are provided responsive to these signals representing the number of free registers for providing a hold indication when there are insufficient free resources available for a task.
SUBSTITUTE: SKΞE
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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3760365A (en) * 1971-12-30 1973-09-18 Ibm Multiprocessing computing system with task assignment at the instruction level
EP0020202A1 (en) * 1979-05-23 1980-12-10 Thomson-Csf Multiprocessing system for signal treatment

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3760365A (en) * 1971-12-30 1973-09-18 Ibm Multiprocessing computing system with task assignment at the instruction level
EP0020202A1 (en) * 1979-05-23 1980-12-10 Thomson-Csf Multiprocessing system for signal treatment

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