Difference between revisions of "64 bit"
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| − | A '''64-bit''' processor is one that generally supports a word size of 2 | + | A '''64-bit''' processor is one that generally supports a word size of 2<sup>64</sup>, where the constant "[[maxint]]" has the value 2<sup>64</sup>-1, or 18,446,744,073,709,551,615. The signed version of this number can express a range of -18,446,744,073,709,551,615..0 and 0..18,446,744,073,709,551,615. The unsigned version of this number can express a range of 0..18,446,744,073,709,551,616. It also means that programs and data spaces can be much larger than on the older 32-bit and 16-bit machines. |
Examples of 32-bit processors include | Examples of 32-bit processors include | ||
| − | * Newer versions of the X86 microcomputer (WINTEL architecture) | + | * Newer versions of the X86 microcomputer, Itanium and newer, AMD64 (WINTEL architecture) |
Currently, 64-bit processors (X86) are enhancements of 32-bit processors, and generally can run 32-bit and 16-bit applications. The reverse, however, is not true; 64-bit code cannot run on a machine smaller than 64 bits. | Currently, 64-bit processors (X86) are enhancements of 32-bit processors, and generally can run 32-bit and 16-bit applications. The reverse, however, is not true; 64-bit code cannot run on a machine smaller than 64 bits. | ||
Latest revision as of 14:25, 10 October 2020
A 64-bit processor is one that generally supports a word size of 264, where the constant "maxint" has the value 264-1, or 18,446,744,073,709,551,615. The signed version of this number can express a range of -18,446,744,073,709,551,615..0 and 0..18,446,744,073,709,551,615. The unsigned version of this number can express a range of 0..18,446,744,073,709,551,616. It also means that programs and data spaces can be much larger than on the older 32-bit and 16-bit machines.
Examples of 32-bit processors include
- Newer versions of the X86 microcomputer, Itanium and newer, AMD64 (WINTEL architecture)
Currently, 64-bit processors (X86) are enhancements of 32-bit processors, and generally can run 32-bit and 16-bit applications. The reverse, however, is not true; 64-bit code cannot run on a machine smaller than 64 bits.
