Search results
Results from the WOW.Com Content Network
In languages that allow pointer arithmetic, arithmetic on pointers takes into account the size of the type. For example, adding an integer number to a pointer produces another pointer that points to an address that is higher by that number times the size of the type.
Pointer formats are known as near, far, or huge. Near pointers are 16-bit offsets within the reference segment, i.e. DS for data and CS for code. They are the fastest pointers, but are limited to point to 64 KB of memory (to the associated segment of the data type). Near pointers can be held in registers (typically SI and DI).
The following example demonstrates dynamic loop unrolling for a simple program written in C. Unlike the assembler example above, pointer/index arithmetic is still generated by the compiler in this example because a variable (i) is still used to address the array element.
For example, when shifting a 32 bit unsigned integer, a shift amount of 32 or higher would be undefined. Example: If the variable ch contains the bit pattern 11100101, then ch >> 1 will produce the result 01110010, and ch >> 2 will produce 00111001. Here blank spaces are generated simultaneously on the left when the bits are shifted to the right.
Set when an arithmetic result is zero, and cleared when it is non-zero. N Negative flag. Set to a copy of the most significant bit of an arithmetic result. V Overflow flag. Set in case of two's complement overflow. S Sign flag. Unique to AVR, this is always N⊕V, and shows the true sign of a comparison. H Half-carry flag.
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.
Increment shadow stack pointer 3 Tiger Lake, Zen 3: INCSSPQ r64: F3 REX.W 0F AE /5: RDSSPD r32: F3 0F 1E /1: Read shadow stack pointer into register (low 32 bits) [a] RDSSPQ r64: F3 REX.W 0F 1E /1: Read shadow stack pointer into register (full 64 bits) [a] SAVEPREVSSP: F3 0F 01 EA: Save previous shadow stack pointer RSTORSSP m64: F3 0F 01 /5
Any pointer (four bytes) will be 4-byte aligned. (e.g.: char*, int*) ... unaligned to cache lines could lead to performance degradation. Here is an example to ...