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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Instruction processing Instruction set architectures.

Instruction Set

Motorola’s designers attempted to make the assembly language orthogonal while the underlying machine language was somewhat less so. Unlike PDP, the MC used separate registers to store data and the addresses of data in memory.

The binary-compatible Z80 later added prefix-codes to escape from this 1-byte limit and allow for a more powerful instruction set. Processor register Register file Memory buffer Program counter Stack. 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. This article possibly contains original research. Every integer instruction could operate on either 1-byte or 2-byte integers and could access data stored in registers, stored as part of the instruction, stored in memory, or stored in memory and pointed to by addresses in registers.

November Learn how and when to remove this template message. An assembly-language programmer or compiler writer had to be mindful of which operations were possible on each register: In many CISC computers, an instruction could access either registers or memory, usually in several different ways. Even the PC and the stack pointer could be affected by the ordinary instructions using all of the ordinary data modes.


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Orthogonal instruction set

This trade off is made explicitly to enable the use of much larger register sets, extended virtual addresses, and longer immediate data data stored directly within the computer instruction. Designers of RISC architectures strove to achieve a balance that they thought better. This was largely due to befehlsatz desire to keep all opcodes one byte long. 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?

The Essentials of Computer Organization and Architecture. befehlssahz

April Learn how and when to remove this template message. Since the PDP was an octal-oriented 3-bit sub-byte machine addressing modes 0—7, registers R0—R7there were electronically 8 gefehlssatz modes. By using this site, you agree to the Terms of Use and Privacy Policy. Branch prediction Memory dependence prediction.

Orthogonal instruction set – Wikipedia

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Unsourced material may be challenged and removed. This section does not cite any sources. Since addressing modes were identical, this made 13 electronic addressing modes, but as in the PDP, the use of the Stack Pointer R14 and Program Counter R15 created a total of over 15 conceptual addressing modes with the assembler program translating the source code into the actual stack-pointer or program-counter based addressing mode needed.

8051 Instruction Set

Learn how and when to remove these template messages. It is ” orthogonal ” in the sense that the instruction type and the addressing 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 With the exception of its floating point instructions, befehlssazt PDP was very strongly orthogonal.


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This article has multiple issues. Please help improve it or discuss these issues on the talk page. The same basic idea was employed for the Intelalthough, to allow for more radical extensions, binary -compatibility with the was not attempted here. The bit extension of this architecture that was introduced with thewas somewhat more orthogonal despite keeping all the instructions and their extended counterparts.

Please improve it by verifying the claims made and adding inline citations. Conversely, data must be in registers before it can be operated upon by the other instructions in the computer’s instruction set.

Please help improve this article by adding citations to befehpssatz sources. 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. Through the use of the Stack Pointer R6 and Program Counter R7 as referenceable registers, there were 10 conceptual addressing modes available.

An orthogonal instruction set does not impose a limitation that requires a certain instruction to use a specific register.

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.

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