A Question on Processor and Memmory
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I am reading Programming Embedded Systems In this book, I came across this claim:
The amount of memory required can also affect the processor selection. In general, the register width of a processor establishes the upper limit of the amount of memory it can access (e.g., a 16-bit address register can address only 64 KB (216 ) memory locations). [*] [*] The narrower the register width, the more likely it is that the processor employs tricks such as multiple address spaces to support more memory. There are still embedded systems that do the job with a few hundred bytes. However, several thousand bytes is a more likely minimum, even on an 8-bit processor.THis really didn't make any sense to me. Can anyone shed some light on this?"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson "Why is it drug addicts and computer afficionados are both called users?" - Clifford Stoll
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I am reading Programming Embedded Systems In this book, I came across this claim:
The amount of memory required can also affect the processor selection. In general, the register width of a processor establishes the upper limit of the amount of memory it can access (e.g., a 16-bit address register can address only 64 KB (216 ) memory locations). [*] [*] The narrower the register width, the more likely it is that the processor employs tricks such as multiple address spaces to support more memory. There are still embedded systems that do the job with a few hundred bytes. However, several thousand bytes is a more likely minimum, even on an 8-bit processor.THis really didn't make any sense to me. Can anyone shed some light on this?"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson "Why is it drug addicts and computer afficionados are both called users?" - Clifford Stoll
What part do you need clarified? In a typical general purpose CPU, the number of bits in a register determines how much memory a CPU can address, since a memory address must be able to fit in the register. An 8-bit register can hold values from 0x00 to 0xFF and can only directly address 256 memory addresses. A 16-bit register can hold values from 0x0000 to 0xFFFF and can access memory addresses in that range, which is 64 KB. In some CPUs they use tricks to get around that limitation, such as memory paging, where you somehow use more than one register to access banks of memory. For example, they might use one register to select the particular bank of memory, then another register to select the memory address within that bank. In other cases they get away from von Neumann architecture and use Harvard architecture, where program and data memory are in separate banks, so you can effectively access a full bank for your program code and another full bank for the data.
CQ de W5ALT
Walt Fair, Jr., P. E. Comport Computing Specializing in Technical Engineering Software
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I am reading Programming Embedded Systems In this book, I came across this claim:
The amount of memory required can also affect the processor selection. In general, the register width of a processor establishes the upper limit of the amount of memory it can access (e.g., a 16-bit address register can address only 64 KB (216 ) memory locations). [*] [*] The narrower the register width, the more likely it is that the processor employs tricks such as multiple address spaces to support more memory. There are still embedded systems that do the job with a few hundred bytes. However, several thousand bytes is a more likely minimum, even on an 8-bit processor.THis really didn't make any sense to me. Can anyone shed some light on this?"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson "Why is it drug addicts and computer afficionados are both called users?" - Clifford Stoll
Consider it a history lesson from last century!
Software rusts. Simon Stephenson, ca 1994.