AMD64
86-64

Theinstruction set which was loadedontothe microprocessor of the AMD corporation,in order to be able to correspondtothe data and memory address of 64 bit width, expands x86order.It is installedin the Opteronseries andthe Athlon 64 series etc..

As forx86instruction set, with theinstruction set whichoriginally, is adopted for the microprocessorof the 80x86 series of the Intelcorporation, as for present specificationit issomething of 32 bitcorrespondence whichis introduced from i386.The Intel corporation whenthe microprocessorof 64 bits is designed, does againto defineinstruction set from one, it is joint with the Hewlett-Packard corporation and it is completely new, (is not)"IA-64 " architectureof compatibilitywas developeduntil recently.

As for this because it is the completely new design,the existingsoftware is operated, it isnecessary to convert32bit order to 64 bit order, amount of the processing which depends on conversion, 32 bit processor compared to operating speed being inferior, the stripe it is uninformed said. ... The continuation is read

Vis-a-vis this,the AMD corporation which is the competitive processor manufacturerof the Intelcorporation developedindividual x86-64 architecture as the approach which can utilize existing software propertyeffectively. As for this,whilex86instruction set taking over, beingsomething whichdoes the expansion to 64 bits,to execute at the speed whereeither the software of 32 bits is not inferioruntil recentlyit is possible the software which is expanded to 64 bits to high speed.

With x86-64,the dataand the like of 64 bit width can be handled, "Long Mode" and,the dataof 32 bit width is handled, operational mode of 2 types "of Legacy Mode" is prepared. When64 bit extended function is used,atOS levelmode of the microprocessor is modified in Long Mode. Legacy Mode isformerx86instruction set and full compatible mode.

Whenthe microprocessor is operational with Long Mode,also it is possible for the microprocessor to execute because it reaches the point where both of 64 bit cord/code and 32 bit cord/code can be executed, calling32bit based library from the program which is written in 64 bit base.

The name, "x86-64" was modified to "AMD64" attendant upon the formal release of the on-board processor. After that,alsothe Intel corporation AMD64 interchangeable 64bitfunction "Extension Memory 64 Technology" (EM64T) has announced offer.