Search results
Results from the WOW.Com Content Network
Below is the full 8086/8088 instruction set of Intel (81 instructions total). [2] These instructions are also available in 32-bit mode, in which they operate on 32-bit registers ( eax , ebx , etc.) and values instead of their 16-bit ( ax , bx , etc.) counterparts.
Finally, the AVRtiny core deletes the 2-word LDS and STS instructions for direct RAM addressing, and instead uses the opcode space previously assigned to the load/store with displacement instructions for new 1-word LDS and STS instructions which can access the first 128 locations of general-purpose RAM, addresses 0x40 to 0xBF.
Instructions to load both extended segment register and general-purpose register at once, similar to 8086's LDS and LES instructions MOV DS2,r16,m32: 0F 3E /r: DS2: 63: Segment-override prefixes for the DS2 and DS3 extended segments. DS3: D6: IRAM: F1: Register File Override Prefix. Will cause memory operands to index into register file rather ...
x86 assembly language is a family of low-level programming languages that are used to produce object code for the x86 class of processors. These languages provide backward compatibility with CPUs dating back to the Intel 8008 microprocessor, introduced in April 1972.
The VIA/Zhaoxin PadLock instructions are instructions designed to apply cryptographic primitives in bulk, similar to the 8086 repeated string instructions. As such, unless otherwise specified, they take, as applicable, pointers to source data in ES:rSI and destination data in ES:rDI, and a data-size or count in rCX.
In real mode, code may also modify the CS register by making a far jump (or using an undocumented POP CS instruction on the 8086 or 8088). [4] Of course, in real mode, there are no privilege levels; all programs have absolute unchecked access to all of memory and all CPU instructions.
The REX prefix provides additional space for encoding 64-bit addressing modes and additional registers present in the x86-64 architecture. Bit-field W changes the operand size to 64 bits, R expands reg to 4 bits, B expands r/m (or opreg in the few opcodes that encode the register in the 3 lowest opcode bits, such as "POP reg"), and X and B expand index and base in the SIB byte.
Adding BCD numbers using these opcodes is a complex task, and requires many instructions to add even modest numbers. It can also require a large amount of memory. [ 2 ] If only doing integer calculations, then all integer calculations are exact, so the radix of the number representation is not important for accuracy.