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CPU of the Day: UTMC UT69R000: The RISC with a Trick (2019)
- drivers99 4y ago> The UT69R000 [has] a 64K data space and a 1M address space. So the virtual address space is 1M but it can only physically interface with 64K of memory?
- hummus_bae 4y agoThe chip itself can have up to 64k Flash (and another 64k of RAM). But the CPU accesses the memory via a MMU that can map the 1M address space into (mostly) 64k chunks. So effectively the OS can use 1M physical addresses and the CPU itself uses close to 64k of them (depending on how you configure the MMU). edit: so the whole address space of 1M can be mapped via the MMU into 64k installments.
- AnotherGoodName 4y agoPretty similar to many CPUs of that era. x86 included. https://en.wikipedia.org/wiki/X86_memory_segmentation https://en.wikipedia.org/wiki/X86_memory_segmentation
- postalrat 4y agoAnd the many mappers NES and other consoles used: https://www.nesdev.org/wiki/Mapper https://www.nesdev.org/wiki/Mapper
- snvzz 4y agoReminder that RISC/CISC are labels placed upon an ISA (the software-hardware interface). The microarchitecture (how the CPU is internally designed, how it executes instructions) is irrelevant to RISC vs CISC.
- steponlego 4y agoThis might be mostly true now but wasn't always.
- somat 4y agoIf curious as to what a 1750 architecture cpu is. there is this. http://www.xgc-tek.com/manuals/mil-std-1750a/ http://www.xgc-tek.com/manuals/mil-std-1750a/
- formerly_proven 4y ago> Copyright © 1980, 1982 by USAF Isn't that an oxymoron?
- somat 4y agoTrue, My understanding is works created by the federal government are for the public good and are as such in the public domain. Note that they can still limit distribution. mainly this is done via classifying the work. Also note the public domain may not apply to works created for the federal government by a third party. final note. The good state governments follow the federal government in placing things in the public domain, but some states try to copyright works they have made. Boo hiss.