memory-mapping

问题 As I understand it, C volatile and optionally inline asm for memory fence have been used for implementing a device driver on top of memory mapped I/O. Several examples can be found in Linux kernel. If we forget about the risk of uncaught exceptions (if any,) does it make sense to replace them with C++11 atomics? Or, is it possible at all? 回答1: In general, you can replace memory fences with atomics, but not volatile , except where it is used together with a fence exclusively for inter thread

问题 Larger memories have higher decoding delay; why is the register file a part of the memory then? Does it only mean that the registers are "mapped" SRAM registers that are stored inside the microprocessor? If not, what would be the benefit of using registers as they won't be any faster than accessing RAM? Furthermore, what would be the use of them at all? I mean these are just a part of the memory so I don't see the point of having them anymore. Having them would be just as costly as

问题 Larger memories have higher decoding delay; why is the register file a part of the memory then? Does it only mean that the registers are "mapped" SRAM registers that are stored inside the microprocessor? If not, what would be the benefit of using registers as they won't be any faster than accessing RAM? Furthermore, what would be the use of them at all? I mean these are just a part of the memory so I don't see the point of having them anymore. Having them would be just as costly as

问题 Larger memories have higher decoding delay; why is the register file a part of the memory then? Does it only mean that the registers are "mapped" SRAM registers that are stored inside the microprocessor? If not, what would be the benefit of using registers as they won't be any faster than accessing RAM? Furthermore, what would be the use of them at all? I mean these are just a part of the memory so I don't see the point of having them anymore. Having them would be just as costly as

问题 I am very confused with Memory Map and Memory mapped I/O. Do general purpose registers for example in ARM Architecture r0, r1, and etc are generally memory mapped? Please help. 回答1: No, those registers are inside the actual CPU (or CPU core for multi-core CPUs). You can not access them through memory. A memory-mapped register is something which you access through an address or a pointer (in languages that has pointers). I/O devices often have memory-mapped registers, where you write to or

问题 I am very confused with Memory Map and Memory mapped I/O. Do general purpose registers for example in ARM Architecture r0, r1, and etc are generally memory mapped? Please help. 回答1: No, those registers are inside the actual CPU (or CPU core for multi-core CPUs). You can not access them through memory. A memory-mapped register is something which you access through an address or a pointer (in languages that has pointers). I/O devices often have memory-mapped registers, where you write to or

问题 I am very confused with Memory Map and Memory mapped I/O. Do general purpose registers for example in ARM Architecture r0, r1, and etc are generally memory mapped? Please help. 回答1: No, those registers are inside the actual CPU (or CPU core for multi-core CPUs). You can not access them through memory. A memory-mapped register is something which you access through an address or a pointer (in languages that has pointers). I/O devices often have memory-mapped registers, where you write to or

问题 There exists the mmap module for node.js: https://github.com/bnoordhuis/node-mmap/ As the author Ben Noordhuis notes, accesing mapped memory can block, which is why he does not recommend it anymore and discontinued it. So I wonder how would I design a non-blocking memory mapping module for node.js? Threading, Fibers, ? Obviously this nearby raises the question if threading in node.js would just happen elsewhere instead of the request handler. 回答1: When talking about implementing some native

问题 i am writing a piece of code that needs to store 10k of memory located in specific physical address before the SOC shuts down. My problem is that this physical address is not part of kernel space so i have to create an ad -hoc memory mapping so i can access this memory space. i tried using io-remap but it doesn't (apparently) work on non-kernel space. is there any API for doing this ? should i used kmap ? Thanks in advance 回答1: Sounds like memory mapped peripheral. For tight binding into your

问题 i am writing a piece of code that needs to store 10k of memory located in specific physical address before the SOC shuts down. My problem is that this physical address is not part of kernel space so i have to create an ad -hoc memory mapping so i can access this memory space. i tried using io-remap but it doesn't (apparently) work on non-kernel space. is there any API for doing this ? should i used kmap ? Thanks in advance 回答1: Sounds like memory mapped peripheral. For tight binding into your