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P.S. I synthesize and re-write in my own words what books teach, write any example programs they contain, solve all exercises they offer, and comment cursively. I list pages done vs total pages, including any roman and appendix numbering.
SCO Ed6 Page6 - Phase1 0006/2384
Each register can hold starting from minimum 1 binary up to a certain maximum of binaries, defined by the specific hardware architecture. Gates also form the main computing engine itself.
The proceeding level, level 1, is the micro-architecture level. Here we see a collection of typically 8 to 32 registers that form a local memory and a circuit called Arithmetic Logic Unit (ALU). The ALU does simple arithmetic operations. Certain registers are connected to the ALU and together form a data path over which data flows. The data path selects registers and has the ALU operate on them, for example, adding them together, and then storing the result in another register.
On some machines, especially older machines, these operations are controlled by a program called microprogram. But on other machines, especially newer machines, the data path is directly controlled by the hardware. In older editions of the book level 1 was called the micro programming level, since a interpreter software was involved. In newer editions the name of this level is renamed into micro architecture level.
Software control of the data path was instructed with a level 2 language program that then was interpreted by level 1 software. Such a program would fetch, examine, and execute instructions one by one, via the data path. On a modern machine with hard-wired control of the data path, similar steps take place but without an explicitly stored program directing these..
The book calls level 2 the Instruction Set Architecture level (ISA level). Computer manufacturers publish manuals for each computer they sell that describe the principles that apply to the ISA level of their product.
The level above the 2nd is usually a hybrid level. This 3th level carries some of the same instructions as level 2 + some additional instructions and a different memory organization, the ability to run two or more programs simultaneously and more. Level 3 designs can differ widely between computers on the contrary to level 1 and 2 designs which are more universal (on the same level). The new level 3 instructions are interpreted by a level 2 interpreter. This interpreter has historically been called an operating system. Those instructions on level 3 that are also used on level 2 are executed directly by the microprogram or the equivalent hardwired hardware control.
SCO Ed6 Page6 - Phase1 0006/2384
Each register can hold starting from minimum 1 binary up to a certain maximum of binaries, defined by the specific hardware architecture. Gates also form the main computing engine itself.
The proceeding level, level 1, is the micro-architecture level. Here we see a collection of typically 8 to 32 registers that form a local memory and a circuit called Arithmetic Logic Unit (ALU). The ALU does simple arithmetic operations. Certain registers are connected to the ALU and together form a data path over which data flows. The data path selects registers and has the ALU operate on them, for example, adding them together, and then storing the result in another register.
On some machines, especially older machines, these operations are controlled by a program called microprogram. But on other machines, especially newer machines, the data path is directly controlled by the hardware. In older editions of the book level 1 was called the micro programming level, since a interpreter software was involved. In newer editions the name of this level is renamed into micro architecture level.
Software control of the data path was instructed with a level 2 language program that then was interpreted by level 1 software. Such a program would fetch, examine, and execute instructions one by one, via the data path. On a modern machine with hard-wired control of the data path, similar steps take place but without an explicitly stored program directing these..
The book calls level 2 the Instruction Set Architecture level (ISA level). Computer manufacturers publish manuals for each computer they sell that describe the principles that apply to the ISA level of their product.
The level above the 2nd is usually a hybrid level. This 3th level carries some of the same instructions as level 2 + some additional instructions and a different memory organization, the ability to run two or more programs simultaneously and more. Level 3 designs can differ widely between computers on the contrary to level 1 and 2 designs which are more universal (on the same level). The new level 3 instructions are interpreted by a level 2 interpreter. This interpreter has historically been called an operating system. Those instructions on level 3 that are also used on level 2 are executed directly by the microprogram or the equivalent hardwired hardware control.
