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Pointer arithmetic cannot be performed on void pointers because the void type has no size, and thus the pointed address can not be added to, although gcc and other compilers will perform byte arithmetic on void* as a non-standard extension, treating it as if it were char *.
As the accumulator and index register sizes are independently settable, it is possible, for example, to have the accumulator set to eight bits and the index registers set to 16 bits, giving the programmer the ability to manipulate individual bytes over a 64KB range without having to perform pointer arithmetic.
In contrast, in the pointer machine model, read and write operations use addresses stored in pointers, and it is not allowed to perform arithmetic operations on these pointers. In both models, data values may be added, and bitwise Boolean operations and binary shift operations may typically also be performed on them, in unit time per operation.
When performed on a negative value in a signed type, the result is technically implementation-defined (compiler dependent), [5] however most compilers will perform an arithmetic shift, causing the blank to be filled with the set sign bit of the left operand. Right shift can be used to divide a bit pattern by 2 as shown:
Usually, some memory registers (triggering ports) within common address space perform an assigned operation when the instruction references them. For example, in an OISC using a single memory-to-memory copy instruction, this is done by triggering ports that perform arithmetic and instruction pointer jumps when written to.
The increment operator increases, and the decrement operator decreases, the value of its operand by 1. The operand must have an arithmetic or pointer data type, and must refer to a modifiable data object. Pointers values are increased (or decreased) by an amount that makes them point to the next (or previous) element adjacent in memory.
The hardware to manipulate these representations is less costly than floating point, and it can be used to perform normal integer operations, too. Binary fixed point is usually used in special-purpose applications on embedded processors that can only do integer arithmetic, but decimal fixed point is common in commercial applications.
Arithmetic logic unit (ALU) – a digital circuit that performs arithmetic and bitwise logical operations on integer binary numbers; Floating-point unit (FPU) – the same as ALU but for floating-point numbers; Load–store unit; Bulldozer (microarchitecture) – another CPU microarchitecture that includes multiple AGUs, developed by AMD