Abstract:
An information-processing device that executes a specific process more frequently than other processes among a variety of processes is provided. The information-processing device includes a first processor capable of executing an instruction set corresponding to the variety of processes, and a second processor capable of executing a portion of or the entire instruction set, the second processor being capable of executing a part of the instruction set corresponding to the specific process more efficiently than the first processor, wherein the second processor executes the specific process whereas the first processor executes the other processes. Accordingly, the information-processing device can execute a variety of instructions efficiently.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention generally relates to an information-processing device, and more particularly relates to an information-processing device that executes both general-purpose processing and transaction processing of data. 
   2. Description of the Related Art 
   Current high-performance general-purpose processors are usually designed to rapidly execute instructions suitable for a wide variety of applications such as commercial applications, scientific applications and multimedia processing. For instance, a current high-performance general-purpose processor includes a floating-point unit so as to rapidly execute scientific applications that require execution of a large amount of floating-point arithmetic operations. In general, high-performance general-purpose processors are designed to execute a single program consisting of a series of instructions. In order to execute the series of instructions rapidly, each high-performance general-purpose processor includes a function to predict a branch outcome for executing a branch instruction before a branch direction is known, a reservation station for efficient out-of-order execution of instructions, and a reorder buffer for keeping track of results from the instructions executed out of order. 
   However, recently, a demand for computers has been increasing especially in areas of systems that execute transaction processing and web server processing. Operations executed in the transaction processing and the web server processing are mainly logical operations and integer operations so that a frequency of executing the floating-point arithmetic operations is low in the transaction processing and the web server processing. In addition, in the transaction processing and the web server processing, a performance to concurrently execute a large number of small-sized processes takes priority over a performance to execute a single large-sized program rapidly. 
   As described above, the current high-performance general-purpose processors are designed to achieve high performance over a wide computing area, and thus include a large amount of hardware inefficiently utilized for executing the transaction processing and the web server processing. Additionally, a large amount of hardware required for rapid execution of a single large-sized sequential program is overkill for concurrent execution of large quantities of simple processes as required in the transaction processing and the web server processing without carrying overhead hardware for functions rarely required. Therefore, there has been a demand for an information-processing device that can rapidly execute the transaction processing and the web server processing. 
   A description will now be given of a conventional high-performance general-purpose processor with reference to  FIG. 1 . A high-performance general-purpose processor  1  shown in  FIG. 1  includes an instruction cache and instruction control unit  2 , a branch-prediction unit  3 , a program counter  4 , a checkpoint unit  5 , a fixed-point register file  6 , a floating-point register file  7 , a fixed-point reorder buffer  8 , a floating-point reorder buffer  9 , a fixed-point reservation station  10 , a floating-point reservation station  11 , a load/store reservation station  12 , a fixed-point unit  13 , a floating-point unit  14 , a load/store unit  15  and a data cache  16 . 
   The instruction cache and instruction control unit  2  stores instructions, as well as fetches and distributes instructions to be executed. Each unit in the high-performance general-purpose processor  1  is controlled by a result of decoding fetched instructions. The branch-prediction unit  3  detects a conditional branch instruction from decoded instructions, and predicts a direction of each branch before a branching condition is known. The program counter  4  points to an address of an instruction being executed in order. The checkpoint unit  5  stores a processor status including register values and the like when a branch instruction is executed based on a branch prediction. If the branch prediction has been proved wrong, the high-performance general-purpose processor  1  can recover the processor status including the register values before branching by reading information stored in the checkpoint unit  5 , thereby recovering from a branch prediction error. 
   The fixed-point register file  6  stores operands for fixed-point operations, and supplies the operands necessary to execute the operation to the fixed-point reservation station  10 . Additionally, the fixed-point register file  6  stores operands for load/store instructions, and supplies the operands necessary to execute the instruction to the load/store reservation station  12 . The fixed-point reorder buffer  8  stores results of calculations executed by the fixed-point unit  13  and results of load instructions executed by the load/store unit  15 . Additionally, the fixed-point reorder buffer  8  has capability of rectifying an order of generated results as if they were generated in order, and supplies correct operands to corresponding reservation stations. 
   The floating-point register file  7  stores operands for floating-point operations, and supplies the operands necessary to execute the operation to the floating-point reservation station  11 . Additionally, the floating-point register file  7  stores operands for load/store instructions, and supplies the operands necessary to execute the instruction to the load/store reservation station  12 . The floating-point reorder buffer  9  stores results of calculations executed by the floating-point unit  14  and results of a load instruction executed by the load/store unit  15 . Additionally, the floating-point reorder buffer  9  has capability of rectifying an order of generated results as if they were generated in order, and supplies correct operands to corresponding reservation stations. 
   The fixed-point reservation station  10  stores fixed-point instructions used for executing fixed-point operations. The fixed-point reservation station  10  waits for operands necessary to execute fixed-point instructions to be supplied from the fixed-point register file  6 , from the fixed-point reorder buffer  8 , or directly from the fixed-point unit  13  or the load/store unit  15 . The fixed-point instructions stored in the fixed-point reservation station  10  become executable after receiving all the operands necessary to execute the instructions. In such a case, the fixed-point reservation station  10  selects executable instructions, and supplies the executable instructions to the fixed-point unit  13 . The maximum number of fixed-point instructions the fixed-point reservation station  10  can supply simultaneously to the fixed-point unit  13  is equal to the number of fixed-point operation modules provided in the fixed-point unit  13 . It should be noted that the fixed-point unit  13  includes a plurality of the fixed-point operation modules, each fixed-point operation module executing the instructions supplied from the fixed-point reservation station  10 . 
   The floating-point reservation station  11  stores floating-point instructions used for executing floating-point operations. The floating-point reservation station  11  waits for operands necessary to execute floating-point instructions to be supplied from the floating-point register file  7 , from the floating-point reorder buffer  9 , or directly from the floating-point unit  14  or the load/store unit  15 . The floating-point instructions stored in the floating-point reservation station  11  become executable after receiving all the operands necessary to execute the instructions. In such case, the floating-point reservation station  11  selects executable instructions, and supplies the executable instructions to the floating-point unit  14 . The maximum number of floating-point instructions the floating-point reservation station  11  can supply simultaneously to the floating-point unit  14  is equal to the number of floating-point operation modules provided in the floating-point unit  14 . It should be noted that the floating-point unit  14  includes a plurality of the floating-point operation modules, each floating-point operation module executing the instructions supplied from the floating-point reservation station  11 . 
   The load/store reservation station  12  stores load/store instructions. The load/store reservation station  12  waits for operands necessary to execute load/store instructions to be supplied from the fixed-point register file  6 , the floating-point register file  7 , the fixed-point reorder buffer  8 , or the floating-point reorder buffer  9 . The load/store instructions become executable after receiving all the operands necessary to execute the instructions. In such case, the load/store reservation station  12  selects executable instructions, and supplies the executable instructions to the load/store unit  15 . The maximum number of load/store instructions the load/store reservation station  12  can supply to the load/store unit  15  is equal to the number of load/store operation modules provided in the load/store unit  15 . It should be noted that the load/store unit  15  includes a plurality of the load/store operation modules, each load/store operation module executing the instructions supplied from the load/store reservation station  12 . 
   The fixed-point unit  13  executes the fixed-point instructions supplied from the fixed-point reservation station  10 , and sends results of executed fixed-point operations to the fixed-point reorder buffer  8 , the fixed-point reservation station  10  and the load/store reservation station  12 . Similarly, the floating-point unit  14  executes the floating-point instructions supplied from the floating-point reservation station  11 , and sends results of executed floating-point operations to the floating-point reorder buffer  9 , the floating-point reservation station  11  and the load/store reservation station  12 . Additionally, the load/store unit  15  executes the load/store instructions supplied from the load/store reservation station  12 , and sends results of executed load/store operations to the fixed-point reorder buffer  8  and the fixed-point reservation station  10 , or to the floating-point reorder buffer  9  and the floating-point reservation station  11 . The load/store unit  15  writes data in the data cache  16  when executing a storing instruction. The load/store unit  15  reads data from the data cache  16  when executing a load instruction. 
   The high-performance general-purpose processor  1  can execute both fixed-point arithmetic/logical operations and floating-point arithmetic operations by including the fixed-point unit  13  and the floating-point unit  14 . Additionally, the high-performance general-purpose processor  1  includes the branch-prediction unit  3 , the fixed-point reorder buffer  8 , the floating-point reorder buffer  9 , the fixed-point reservation station  10 , the floating-point reservation station  11  and the load/store reservation station  12  so that the high-performance general-purpose processor  1  can predict a branch direction for executing a branch instruction before a branch direction is known, and can produce results as if instructions are executed in order when real execution takes advantage of out-of-order execution. 
   As described above, the high-performance general-purpose processor  1  is designed to rapidly execute various instructions over the wide computing area, and to execute sequential programs rapidly by using branch prediction and out-of-order execution. The high-performance general-purpose processor  1  also has multiple operation modules in the fixed-point unit  13 , in the floating-point unit  14 , and in the load/store unit  15 . With those operation modules, the high-performance general-purpose processor  1  can execute six to eight instructions simultaneously. 
     FIG. 2  is a block diagram showing a multi-thread transaction processing system. A multi-thread transaction processing system  17  using a multi-thread method includes transaction processors  18 - 1  through  18 -n, a memory  19 , an input/output interface  20  and a system bus  21 . 
   Each of the transaction processors  18 - 1  through  18 -n includes a plurality of program counters for multi-thread processing, thereby executing transaction processes efficiently. The memory  19  is connected through the system bus  21  to the transaction processors  18 - 1  through  18 -n, and is universally used among the transaction processors  18 - 1  through  18 -n. The input/output interface  20  provides an interface connecting the system bus  21  and peripheral devices located outside the multi-thread transaction processing system  17 . 
     FIG. 3  is a block diagram showing a transaction processor. The transaction processor  18 - 1  shown in  FIG. 3  includes an instruction cache and instruction control unit  22 , program counters  23 , register files  24 , a fixed-point unit  25 , a load/store unit  26  and a data cache  27 . It should be noted that the instruction cache and instruction control unit  22 , the program counters  23 , the register files  24 , the fixed-point unit  25 , the load/store unit  26  and the data cache  27  correspond respectively to the instruction cache and instruction control unit  2 , the program counter  4 , the fixed-point register file  6 , the fixed-point unit  13 , the load/store unit  15  and the data cache  16  shown in  FIG. 1 . In addition, each of the transaction processors  18 - 1  through  18 -n has a structure shown in  FIG. 3 . In this embodiment, a floating-point unit is not implemented since cost of hardware is too high compared to performance gain in transaction processing, which does not require floating-point calculations often. Furthermore, the transaction processors  18 - 1  through  18 -n are designed mainly to simultaneously execute a large number of programs, for instance, the number of processors multiplied by the number of program counters in each processor, rather than to execute a single program rapidly, and thus do not include functions to predict branch directions, reorder buffers and reservation stations. Instead, each of the transaction processors  18 - 1  through  18 -n includes a plurality of program counters  23  and the register files  24  for multi-threading. Taking ATM transaction processing as an example, A single process using a single program counter in a transaction processor can handle a withdrawal for a user A, at the same time, a withdrawal for a user B by using another program counter. Consequently, each of the transaction processors  18 - 1  through  18 -n can execute a plurality of ATM transaction processes simultaneously. 
   Recently, processor speed has been increasing substantially, whereas memory speed has not increased as the processor speed. Such a condition makes a long memory access time and a resulting processor stall major performance impediments. In a case that a waiting period to access a memory happens to the transaction processor  18 - 1  while executing a series of instructions for a first process, the transaction processor  18 - 1  can execute another series of instructions for a second process by using another program counter shown in  FIG. 3 , thereby improving overall efficiency of utilizing hardware resources. As described above, the transaction processor  18 - 1  shown in  FIG. 3  can execute transaction processes efficiently. 
   The multi-thread transaction processing system  17  shown in  FIG. 2  can execute a large number of processes simultaneously, and can execute transaction processes efficiently by including the transaction processors  18 - 1  through  18 -n. In addition, a size of each transaction processor shown in  FIG. 3  is smaller than the high-performance general-purpose processor so that multiple transaction processors can be fabricated on a single chip. 
   The high-performance general-purpose processor  1  shown in  FIG. 1  includes many functions that are not cost-effective to execute simple transaction processes and web server processes as the high-performance general-purpose processor  1  is designed to execute a wide variety of applications efficiently. Additionally, the high-performance general-purpose processor  1  is less efficient for execution of large quantities of simple processes necessary in the transaction processes and the web server processes, since the high-performance general-purpose processor  1  is designed to execute a single program at a time. Even if an attempt to provide a plurality of high-performance general-purpose processors  1  in a system is made, the number of concurrently executed processes is less since the number of the high-performance general-purpose processors  1  that can be fabricated on a single chip is less because of its large circuit size. 
   On the other hand, in a case that a system includes only the multi-thread transaction processing system  17  shown in  FIG. 2 , the system can improve efficiency to execute transaction processes and/or web server processes, but cannot rapidly execute complicated processes such as a scientific arithmetic operation that needs floating-point arithmetic operations or a large process blocking execution of other small processes. Further, the system including only the multi-thread transaction processing system  17  does not have various functions to execute a single program rapidly. Accordingly, in a case that the system is asked to execute a single large-sized process or a complicated process, efficiency to execute such a process by the system decreases remarkably. 
   SUMMARY OF THE INVENTION 
   Accordingly, it is a general object of the present invention to provide an information-processing device capable of processing a variety of instructions efficiently. A more specific object of the present invention is to provide an information-processing device including processors, wherein the processors divide execution of instructions among them, thereby efficiently executing the instructions. 
   The above-described object of the present invention is achieved by an information-processing device that executes a specific process more frequently than other processes among a variety of processes, the information-processing device including a first processor capable of executing an instruction set corresponding to the variety of processes, and a second processor capable of executing a portion of or the entire instruction set, the second processor being capable of executing a part of the instruction set corresponding to the specific process more efficiently than the first processor, wherein the second processor executes the specific process whereas the first processor executes the other processes. 
   Accordingly, the information-processing device can execute a variety of instructions efficiently. 

   
     Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a block diagram showing a high-performance general-purpose processor; 
       FIG. 2  is a block diagram showing a multi-thread transaction processing system; 
       FIG. 3  is a block diagram showing a transaction processor; 
       FIG. 4  is a system diagram showing an embodiment of the present invention; 
       FIG. 5  is a block diagram showing a transaction processor in the embodiment of the present invention; 
       FIG. 6  is a flowchart showing processes to detect instructions lacking capabilities in the transaction processor in the embodiment of the present invention; 
       FIG. 7  is a flowchart showing an interrupting process in preparation to transfer execution of a process to the other type of a processor performed by the transaction processor in the embodiment of the present invention; 
       FIG. 8  is a flowchart showing processes performed by a general-purpose processor to accept transferred execution of the process in the embodiment of the present invention; 
       FIG. 9  is a block diagram showing an instruction-allocating process in the embodiment of the present invention; and 
       FIG. 10  is a flowchart showing processes performed by a processor-allocation control. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   A description will now be given of preferred embodiments of the present invention, with reference to the accompanying drawings. 
     FIG. 4  is a system diagram showing an embodiment of the present invention. An information-processing device  31  according to the embodiment includes general-purpose processors  32 - 1  and  32 - 2 , transaction processors  33 - 1  and  33 - 2 , a main memory  34 , an input/output interface  35 , a system controller  36  and a system bus  37 . 
   Each of the general-purpose processors  32 - 1  and  32 - 2  are processors similar to the high-performance general-purpose processor  1  shown in  FIG. 1 . In other words, each of the general-purpose processors  32 - 1  and  32 - 2  can execute all types of processes rapidly. As each of the general-purpose processors  32 - 1  and  32 - 2  can predict a branch direction for executing a branch instruction before a branch direction is known, can execute instructions out of order. It should be noted that the number of the general-purpose processors  32 - 1  and  32 - 2  included in the information-processing device  31  is not limited to two. Thus, any number of the general-purpose processors can be included in the information-processing device  31  depending on a percentage of load that the other type of a processor cannot handle efficiently. 
   The transaction processors  33 - 1  and  33 - 2  can execute a large number of processes simultaneously. However, a speed of executing each process is slower than that of the general-purpose processors  32 - 1  and  32 - 2 . Additionally, the transaction processors  33 - 1  and  33 - 2  may lack capability of executing certain instructions that are not important for transaction processing. Besides, each of the transaction processors  33 - 1  and  33 - 2  is designed to be a multi-thread system and/or a system including multiple processors, and thus can execute transaction processes efficiently. It should be noted that the number of the transaction processors  33 - 1  and  33 - 2  included in the information-processing device  31  is not limited to two. The information-processing device  31  may include any number of the transaction processors as the ratio of the load require. 
   The main memory  34  includes a RAM (Random Access Memory), and stores data therein. Additionally, the main memory  34  is connected through the system bus  37  to the general-purpose processors  32 - 1  and  32 - 2 , and the transaction processors  33 - 1  and  33 - 2 . Accordingly, the data stored in the main memory  34  is shared among the processors  32 - 1 ,  32 - 2 ,  33 - 1  and  33 - 2 . 
   The input/output interface  35  provides an interface connecting the system bus  37  and peripheral devices located outside the information-processing device  31 . The system controller  36  controls the system bus  37 , the main memory  34  and the input/output interface  35  according to a request to access the main memory  34  or the input/output interface  35  through the system bus  37  from the general-purpose processors  32 - 1  and  32 - 2 , and the transaction processors  33 - 1  and  33 - 2 . 
     FIG. 5  is a block diagram showing a structure of the transaction processor  33 - 1 . The transaction processor  33 - 1  shown in  FIG. 5  includes a transaction-processing unit  41  and a secondary cache data memory  42 . The transaction-processing unit  41  is fabricated on a single semiconductor chip whereto the secondary cache data memory  42  in this embodiment is provided outside the semiconductor chip. The secondary cache data memory  42  may be a RAM, and temporarily stores data and instructions therein. 
   The transaction-processing unit  41  includes processor cores  43 - 1  through  43 -m, a secondary cache tag  44 , an interface  45  and an internal bus  46 . The processor cores  43 - 1  through  43 -m are connected through the internal bus  46  to the secondary cache tag  44  and the interface  45 . The secondary cache tag  44  manages usage of the secondary cache data memory  42 . The interface  45  provides an interface connecting the secondary cache data memory  42  and the internal bus  46 . 
   The processor cores  43 - 1  through  43 -m may have the same structure as the transaction processor  18 - 1  shown in  FIG. 3 . In other words, each of the processor cores  43 - 1  through  43 -m is multi-threaded so as to efficiently execute transaction processes. Additionally, each of the processor cores  43 - 1  through  43 -m does not necessarily need to include functions to execute complicated arithmetic operations such as floating-point arithmetic operations. Furthermore, each of the processor cores also does not necessarily need to include functions to predict branch directions for executing a branch instruction before the branch direction is known, or functions to execute instructions out of order. However, each of the processor cores  43 - 1  through  43 -m is not necessarily multi-threaded since the transaction processors  33 - 1  and  33 - 2  can execute concurrent transaction processes by including a plurality of the processor cores  43 - 1  through  43 -m. Even in an extreme case that each of the transaction processors  33 - 1  and  33 - 2  includes only the processor core  43 - 1 , each of the transaction processors  33 - 1  and  33 - 2  can execute the concurrent transaction processes if the processor core  43 - 1  is specialized in transaction processing with multithreading as described with reference to  FIG. 3 . 
   A description will now be given of processes performed by the transaction processors  33 - 1  and  33 - 2 .  FIG. 6  is a flowchart showing processes performed by the transaction processor according to the embodiment of the present invention. The transaction processor  33 - 1  executes steps S 101  through S 105 . 
   At the step S 101 , the transaction processor  33 - 1  initially issues an instruction. Subsequently, at the step S 102 , the transaction processor  33 - 1  decides whether the instruction is directing execution of a hardware-implemented operation, for example, a fixed-point arithmetic operation. If it is ascertained at the step S 102  that the instruction is directing execution of the hardware-implemented operation, the transaction processor  33 - 1  proceeds to the step S 103 , and executes the instruction. Subsequently, at the step S 104 , the transaction processor  33 - 1  decides whether there is a next instruction to be executed. If it is ascertained at the step S 104  that there is the next instruction to be executed, the transaction processor  33 - 1  proceeds to the step S 101 , and issues the next instruction. If it is ascertained at the step S 104  that the next instruction does not exist, the transaction processor  33 - 1  terminates the above-described processes. 
   If it is ascertained at the step S 102  that the instruction is directing execution of an operation not implemented in hardware, the transaction processor  33 - 1  proceeds to the step S 105 , and generates an interrupt. After generating the interrupt, the transaction processor  33 - 1  terminates the above-described processes. 
   A description will now be given of an interrupt handling process executed by the transaction processor  33 - 1 .  FIG. 7  is a flowchart showing the interrupt handling process executed by the transaction processor according to the embodiment of the present invention. The transaction processor  33 - 1  executes steps S 201  through S 206  as the interrupt handling process. 
   At the step S 201 , the transaction processor  33 - 1  initially analyzes interrupt information that has been generated at the step S 105 . Subsequently, at the step S 202 , the transaction processor  33 - 1  decides whether an incoming interrupt is a regular interrupt or not. If it is ascertained at the step S 202  that the incoming interrupt is the regular interrupt, the transaction processor  33 - 1  proceeds to the step S 203 , and executes the regular interrupt handling process. If it is ascertained at the step S 202  that the interrupt is for executing a non hardware-implemented operation, for example, a floating-point arithmetic operation, the transaction processor  33 - 1  proceeds to the step S 204 . At the step S 204 , the transaction processor  33 - 1  stores an internal condition of the transaction processor  33 - 1  necessary for transferring execution of the non hardware-implemented operation, in a main memory. After storing the internal condition, the transaction processor  33 - 1  proceeds to the step S 205 , then stores an instruction address of the instruction that has been issued at the step S 101  and a memory address of the internal condition stored in the memory, in internal registers of the transaction processor  33 - 1 , and interrupts the general-purpose processor  32 - 1  or  32 - 2 . To be concrete, the transaction processor  33 - 1  interrupts one of the general-purpose processors  32 - 1  and  32 - 2  by supplying an interrupt vector including contents of the above-described internal registers to one of the general-purpose processors  32 - 1  and  32 - 2 . As described above, in a case that the transaction processor  33 - 1  or  33 - 2  detects an instruction to execute a non hardware-implemented operation, for example, a floating-point arithmetic operation, the transaction processor  33 - 1  or  33 - 2  interrupts one of the general-purpose processors  32 - 1  and  32 - 2 . 
   A description will now be given of processes performed by the general-purpose processor  32 - 1 .  FIG. 8  is a flowchart showing processes executed by the general-purpose processor according to the embodiment of the present invention. The general-purpose processor  32 - 1  executes steps S 301  through S 304 . 
   Upon receiving an interrupt request from other processors such as the transaction processors  33 - 1 ,  33 - 2 , the input/output interface  35  or internal units of the general-purpose processor  32 - 1 , the general-purpose processor  32 - 1  starts executing processes transferred from the other type of a processor, at the step S 301 . 
   At the step S 301 , the general-purpose processor  32 - 1  decides whether the interrupt request is a request to the general-purpose processor  32 - 1  for executing a non hardware-implemented instruction transferred from one of the transaction processors  33 - 1  and  33 - 2 . If it is ascertained at the step S 301  that the interrupt request is not the request to the general-purpose processor  32 - 1  for executing an instruction transferred from one of the transaction processors  33 - 1  and  33 - 2 , the general-purpose processor  32 - 1  executes a regular interrupt handling process at the step S 302 , and then terminates the above-described processes. 
   If it is ascertained at the step S 301  that the interrupt request is the request to the general-purpose processor  32 - 1  for executing an instruction transferred from one of the transaction processors  33 - 1  and  33 - 2 , the general-purpose processor  32 - 1  proceeds to the step S 303 , and obtains the interrupt vector supplied with the interrupt request, for instance, from the transaction processor  33 - 1 . Additionally, the general-purpose processor  32 - 1  obtains the instruction address and a memory address from the interrupt vector. The general-purpose processor  32 - 1  copies the internal condition of the transaction processor  33 - 1  therein by using the memory address where the transaction processor  33 - 1  has stored the internal condition. Subsequently, at the step S 304 , the general-purpose processor  32 - 1  executes the instruction located at the above instruction address. In other words, the general-purpose processor  32 - 1  executes instructions starting from the instruction requested by the transaction processor  33 - 1 . As described above, each of the general-purpose processors  32 - 1  and  32 - 2  executes a non hardware-implemented operation, for example, a floating-point arithmetic operation, and instructions following the instruction that could not be executed by the transaction processor  33 - 1  or  33 - 2 . 
   According to the embodiment of the present invention as described above, in a case that an instruction to execute a non hardware-implemented operation such as a floating-point arithmetic operation is detected in the transaction processor  33 - 1  or  33 - 2 , the transaction processor  33 - 1  or  33 - 2  in which the non hardware-implemented operation is detected interrupts the general-purpose processors  32 - 1  or  32 - 2  to let the general-purpose processors  32 - 1  or  32 - 2  execute the non hardware-implemented operation. In the embodiment, execution of the non hardware-implemented operation is transferred from the transaction processor  33 - 1  to the general-purpose processor  32 - 1 . However, any instructions executed inefficiently by the transaction processor but efficiently by the general-purpose processor can be transferred from the transaction processor to the general-purpose processor in addition to non hardware-implemented operations. The present invention includes such embodiments. 
   In the present invention, a transaction process can be executed efficiently by transaction processors. However, an OS (Operating System) may be executed more efficiently by one of the general-purpose processors  32 - 1  and  32 - 2  since general-purpose processors can execute a single instruction stream faster than the transaction processors. However, selection of a processor executing the OS depends on efficiency of executing the OS, and thus the OS is not necessarily executed by one of the general-purpose processors  32 - 1  and  32 - 2 . In other words, the OS may be executed by one of the transaction processors  33 - 1  and  33 - 2 . Additionally, by sharing the main memory  34  among the general-purpose processors  32 - 1  and  32 - 2 , and the transaction processors  33 - 1  and  33 - 2 , the information-processing device  31  can pass a process efficiently between the processors. 
   A description will now be given of a process-allocating method for allocating processes to processors.  FIG. 9  is a diagram showing a process-allocating function according to the embodiment of the present invention. The OS manages allocation of processes or threads stored in a process queue  71 . This process-allocating function of the OS is achieved by a dispatcher  72 . The process queue  71  stores processes to be executed by processors. The dispatcher  72  monitors a process indicated by the process queue  71  as well as monitors the general-purpose processors  32 - 1  and  32 - 2 , and the transaction processors  33 - 1  and  33 - 2 . The dispatcher  72  then allocates the process indicated by the process queue  71  to one of the processors. Since the system according to the present invention mainly executes transaction processes, all the processes are preferably allocated initially to the transaction processors  33 - 1  and  33 - 2  instead of the general-purpose processors  32 - 1  and  32 - 2 . Alternatively, transaction processes may be allocated to the transaction processors  33 - 1  and  33 - 2 , whereas processes initially not proved to be the transaction processes may initially be allocated to the general-purpose processors  32 - 1  and  32 - 2 . Execution of allocated processes will be suspended by a system call (an interrupt by the OS) requesting input/output operations or requesting some system resources that are occupied by some other process. A system call/trap handler  73  suspends execution of processes according to contents of an interrupt when having received the system call from the process being executed or one of the general-purpose processors  32 - 1  and  32 - 2 , and the transaction processors  33 - 1  and  33 - 2 . Interrupt requesting not implemented in hardware described in  FIG. 7  is one of the cause of process suspension, and enters into system call/trap handling. In addition, if execution of a certain process on one of the transaction processors  33 - 1  and  33 - 2  is determined inefficient such by a performance monitor, the process may issue a system call asking the execution be transferred to one of the general purpose processors  32 - 1  and  32 - 2 . 
     FIG. 10  is a flowchart showing the process-allocating function according to the embodiment. The system call/trap handler  73  executes steps S 401  through S 405  shown in  FIG. 10 . The system call/trap handler  73  is invoked by detection of interrupts on system calls from the general-purpose processors  32 - 1  and  32 - 2 , and the transaction processors  33 - 1  and  33 - 2 . The cause of an interrupt on a system call is analyzed at the step S 401 , the system call/trap handler  73  decides whether the processor can resume executing a series of instructions in the process being executed by the processor from an interrupted instruction, at the step S 402 . If it has been determined at the step S 402  that the series of instructions in the process can be resumed by the processor from the interrupted instruction, the system call/trap handler  73  marks the process for executing on the same processor or the same type of the processor at the step S 403 . Subsequently, at the step S 404 , after the cause of suspension is cleared, the system call/trap handler  73  stores the process to which the information has been added in the process queue  71 . The dispatcher  72  selects the process in the process queue  71  as it becomes the first priority for execution and tries to allocate to the same processor as it has been executing. However, in a case that the processor that has been executing the process is now being used for executing another process, the process is allocated to another thread of the processor, or to another processor if they are available. 
   If it is determined at the step S 402  that the process cannot or inefficient to be resumed by the same processor, the system call/trap handler  73  makes the process that limits a type of a processor executing the process to a general-purpose processor at the step S 405 . Subsequently, the system call/trap handler  73  executes the step S 404 . 
   The dispatcher  72  allocates a process to a specified processor if entry in the process queue  71  includes the information that limits a type of a processor executing the process. For instance, in a case that a process including a floating-point arithmetic operation has been initially allocated to a transaction processor, an interrupt occurs in the process. Subsequently, the process is stored with information specifying a general-purpose processor in the process queue  71 . Then the dispatcher  72  allocates the process to one of the general-purpose processors  32 - 1  or  32 - 2 . 
   As described above, the system according to the present invention can efficiently execute processes as a whole by allocating all the processes to one of the transaction processors  32 - 1  and  32 - 2  since main processes executed by the system are transaction processes. Alternatively, the system may allocate transaction processes to a transaction processor, and processes not proved to be the transaction processes to a general-purpose processor initially. In addition, allocation of processes is desirably optimized according to performances of the general-purpose processors  32 - 1  and  32 - 2 , and the transaction processors  33 - 1  and  33 - 2 . In the embodiment, instruction sets may be the same for the general-purpose processors  32 - 1  and  32 - 2 , and the transaction processors  33 - 1  and  33 - 2 . 
   In the above-described embodiment, a description has been given of the system wherein the general-purpose processors  32 - 1  and  32 - 2 , and the transaction processors  33 - 1  and  33 - 2  share the system bus  37  and the main memory  34 . 
   In the above-described invention, there are two types of processors provided in an information-processing device. One of the processors is a general-purpose processor mainly designed to demonstrate high performance over a wide computing area, and to rapidly execute a single program. The other is a multi-thread and/or multi-processing transaction processor mainly designed to execute a large number of small-sized processes concurrently. A transaction process is allocated to the transaction processor. A process that cannot be executed efficiently by the transaction processor is allocated to the general-purpose processor. Accordingly, the present invention provides an information-processing device that can efficiently execute a variety of processes. 
   Additionally, for instance, in a case that an instruction to execute a floating-point arithmetic operation not implemented in hardware is detected in a process being executed by the transaction processor, the transaction processor interrupts the general-purpose processor. Subsequently, the general-purpose processor executes remaining instructions in the process starting from the instruction to execute the floating-point arithmetic operation. Instructions passed from the transaction processor to the general-purpose processor are the instructions that cannot be executed efficiently by the transaction processor but can be executed efficiently by the general-purpose processor. Such instructions are most likely the instructions for executing floating-point arithmetic operation, but are not limited to the floating-point instructions. 
   A process may be judged inefficient to be executed by one type of a processor, by monitoring a performance counter or by some other means. In such a case, a transfer of execution of the process may be requested through a system call to optimize overall performance of the entire system. 
   The above description is provided in order to enable any person skilled in the art to make and use the invention and sets forth the best mode contemplated by the inventors of carrying out the invention. 
   The present invention is not limited to the specially disclosed embodiments and variations, and modifications may be made without departing from the scope and spirit of the invention. 
   The present application is based on Japanese Priority Application No. 2000-348475, filed on Nov. 15, 2000, the entire contents of which are hereby incorporated by reference.