Microcontroller Instruction Set. For interrupt response time information, refer to the hardware description chapter. Note: 1. Operations on SFR byte address Instruction Set. ♢ Introduction. ♢ CIP architecture and memory organization review. ♢ Addressing modes. ➢ Register addressing. ➢ Direct addressing. Instruction hex code. MOVE with immediate data. Hex. Bytes Instruction. 2. MOV A, #immediate. 3. MOV direct, #immediate. 2. MOV @R0, #.

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This page was last edited on 10 Augustat This article possibly contains original research. Motorola’s designers attempted to make the assembly language orthogonal while the underlying machine language was somewhat less so.

Orthogonal instruction set

An orthogonal instruction set does not impose a limitation that requires a certain instruction to use a specific register. Instruction processing Instruction set architectures. However, the encoding-strategy used still shows many traces from the and and Z80 ; for instance, single-byte encodings remain for certain frequent operations such as push and pop of registers and constants, and the primary accumulator, eaxemploy shorter encodings than the other registers on certain types of operations; observations like beffehlssatz are sometimes exploited for code optimization in both compilers and 80051 written code.

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8051 Instruction Set

Please help improve it or discuss these issues on the talk page. Views Read Edit View history. The binary-compatible Z80 later added prefix-codes to escape from this 1-byte limit and allow for a more powerful instruction set.

This compromise gave almost the same convenience as a truly orthogonal machine, and yet also gave the CPU designers freedom to use the bits in the instructions more efficiently than a purely orthogonal approach might have. In the late s research at IBM and similar projects elsewhere demonstrated that the majority of these “orthogonal” addressing modes were ignored by most programs.


Data dependency Structural Control False sharing. Unsourced material may be challenged and removed. The Essentials of Computer Organization and Architecture. Articles that may contain original research from November All articles that may contain original research Articles needing additional references from April All articles needing additional references Articles with multiple maintenance issues Articles needing additional references from April All articles with specifically marked weasel-worded phrases Articles with specifically marked weasel-worded phrases from April With the exception of its floating point instructions, the PDP was very strongly orthogonal.

At the bit level, the person writing the assembler or debugging machine code would clearly see that symbolic instructions could become any of several different op-codes. Perhaps some of the bits that were used to express the fully orthogonal instruction set could instead be used to express more virtual address bits or select from among more registers. April Learn how and when to remove this template message.

Designers of RISC architectures strove to achieve a balance that they thought better. Please help improve this section by adding citations to reliable sources. Please improve it by verifying the claims made and adding inline citations. Since the PDP was an octal-oriented 3-bit sub-byte machine addressing modes 0—7, registers R0—R7there were electronically 8 addressing modes.

Single-core Multi-core Manycore Heterogeneous architecture. In many CISC computers, an instruction could access either registers or memory, usually in several different ways. By using this site, you agree to the Terms of Use and Privacy Policy.

Even the PC and the stack pointer could be affected by the ordinary instructions using all of the ordinary data modes. This resulted in 16 logical addressing modes 0—15however, addressing modes 0—3 were “short immediate” for immediate data of 6 bits or less the 2 low-order bits of the addressing mode being the 2 high-order bits of the immediate data, when prepended to the remaining 4 bits in that data-addressing byte.


Instruction Set Manual: Instruction Set Manual

Please help improve this article by adding citations to reliable sources. This was largely due to a desire to keep all opcodes one byte long. Conversely, data must be in registers before it can be operated upon by the other instructions in the computer’s instruction set.

This article needs additional citations for verification. Statements consisting only of original research should be removed.

Through the use of the Stack Pointer R6 and Program Counter R7 as referenceable registers, there were 10 conceptual addressing modes available. An assembly-language programmer or compiler writer had to be mindful of which operations were possible on each register: Processor register Register file Memory befehlwsatz Program counter Stack.

The bit extension of this architecture that befehlsssatz introduced with thewas somewhat more orthogonal despite keeping all the instructions and their extended counterparts.

The 8-bit Intel as well as the and microprocessor was basically a slightly extended accumulator-based design and therefore not orthogonal. It maintained some degree of non-orthogonality for the sake of high code density even though this was derided as being ” baroque ” by some computer scientists [ who? Branch prediction Memory dependence prediction. It is ” orthogonal ” in the sense that the instruction type and the befehlssqtz mode vary independently.

Each component being one bytethe opcode a value in the range 0—, and each operand consisting of two nibblesthe upper 4 bits specifying an addressing mode, and the lower 4 bits usually specifying a register number R0—R