Search results
Results from the WOW.Com Content Network
For example, the Solaris operating system does so for both SPARC and x86-64. On the Linux side, Debian also ships an ILP32 userspace. The underlying reason is the somewhat "more expensive" nature of LP64 code, [8] just like it has been shown for x86-64. In that regard, the x32 ABI extends the ILP32-on-64bit concept to the x86-64 platform.
In theory, modern byte-addressable 64-bit computers can address 2 64 bytes (16 exbibytes), but in practice the amount of memory is limited by the CPU, the memory controller, or the printed circuit board design (e.g., number of physical memory connectors or amount of soldered-on memory).
In computing, a virtual address space (VAS) or address space is the set of ranges of virtual addresses that an operating system makes available to a process. [1] The range of virtual addresses usually starts at a low address and can extend to the highest address allowed by the computer's instruction set architecture and supported by the operating system's pointer size implementation, which can ...
In logical block addressing, only one number is used to address data, and each linear base address describes a single block. The LBA scheme replaces earlier schemes which exposed the physical details of the storage device to the software of the operating system. Chief among these was the cylinder-head-sector (CHS) scheme, where blocks were addressed by means
The 32-bit size of the virtual address is not changed, so regular application software continues to use instructions with 32-bit addresses and (in a flat memory model) is limited to 4 gigabytes of virtual address space. Operating systems supporting this mode use page tables to map the regular 4 GB virtual address space into the physical memory ...
Their 32-bit linear addresses can address 4 billion different items. Using word addressing, a 32-bit processor could address 4 Gigawords; or 16 Gigabytes using the modern 8-bit byte. If the 386 and its successors had used word addressing, scientists, engineers, and gamers could all have run programs that were 4x larger on 32-bit machines.
The default OperandSize and AddressSize to use for each instruction is given by the D bit of the segment descriptor of the current code segment - D=0 makes both 16-bit, D=1 makes both 32-bit. Additionally, they can be overridden on a per-instruction basis with two new instruction prefixes that were introduced in the 80386:
If clear, the limit is in units of bytes, with a maximum of 2 20 bytes. If set, the limit is in units of 4096-byte pages, for a maximum of 2 32 bytes. D/B D = Default operand size : If clear, this is a 16-bit code segment; if set, this is a 32-bit segment. B = Big: If set, the maximum offset size for a data segment is increased to 32-bit ...