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Please help me remove some of my ignorance: ARM = RISC? Intel = CISC? ? = MIPS? What else is out there in large amounts?
by csours 7y ago
Please help me remove some of my ignorance:
ARM = RISC?
Intel = CISC?
? = MIPS?
What else is out there in large amounts?
- draw_down 7y agohttps://en.wikipedia.org/wiki/MIPS_architecture https://en.wikipedia.org/wiki/MIPS_architecture
- alxmdev 7y agoMIPS itself is a RISC, see https://en.wikipedia.org/wiki/MIPS_architecture https://en.wikipedia.org/wiki/MIPS_architecture As for what else is out there in large numbers, I think a lot of 8bit Z80 and AVR microcontrollers (like the ATmega328 used in Arduino Uno) are embedded in larger systems and go unnoticed. More recently I've seen the Xtensa (32bit RISC) catching on with the popular ESP32 and ESP8266 SOCs.
- deleted 7y ago[deleted]
- saagarjha 7y agoA number of others you might encounter in your embedded devices: 68k, AVR, Z80. (CISC, RISC, CISC, if you’re curious.)
- wk_end 7y agoThere’s (sadly) not that much 68k left these days, is there? Do you know of any specific companies still using them? (maybe ones that are hiring? :)
- wolfgke 7y agoIn terms of hardware: NXP ColdFire.
- zozbot234 7y agoThe Apollo Vampire is a newly-designed implementation on FPGA's that compares very favorably wrt. performance with existing 68k (and ColdFire) hardware.
- kn0where 7y agoI think either Airbus or Boeing (or both?) use them in some of their planes (A320 and/or 737)
- p_l 7y agoAST2500 (popular as BMC chip) has ColdFire coprocessor, TALOS2 and Blackbird (truly open source POWER9 workstations) use it (used?) to bit bang one of the protocols necessary to start up the CPUs
- t0mas88 7y agoI wrote a lot of code for it 12 years ago in embedded programming. It was already getting less popular back then so I guess you're right. Haven't seen one in forever.
- ken 7y agoI assume that all modern CPUs are CISC-ish opcodes running in microcode on a RISC-ish core, and it’s been a few decades since those were useful labels.
- zozbot234 7y agoThere's nothing much that's CISC-like about ARM, MIPS or RISC-V. Even many μC architectures are closer to "RISC" than "CISC", though there's at least some room for exceptions there.
- yjftsjthsd-h 7y ago> There's nothing much that's CISC-like about ARM, I struggle to think that ARM can really be called reduced-instruction after neon or so.
- zozbot234 7y agoWhy? NEON operates on registers, so the load-store principle is still fully in effect. And it maps directly to special-purpose hardware.
- arnd 7y ago32-bit Arm has some features that make it less RISC-like than others: - Predication as a major architectural feature -- every instruction can be conditionally executed - Complex load-store instructions: ldm/stm can operate on a large set of registers in a single instruction, including performing a branch by loading into the instruction pointer - 16-bit Thumb instruction format (also optionally present in RISC-V and newer MIPS) 64-bit Arm mostly drops all of the above and is basically a traditional RISC implementation.
- glangdale 7y agoRISC has never been about reduced number of instructions, but their complexity. A SIMD extension built around load/store architecture is quite compatible with the principles of RISC, despite the fact that such an extension might have very numerous instructions.
- notacoward 7y agoMIPS is sort of the original RISC, since one of the two originators of the RISC concept (Hennessy) was a founder of MIPS Computer Systems in 1984. POWER is also RISC, but basically doesn't have any traction beyond IBM itself. SPARC lives on only in radiation-hardened form for the European space agency. Various others never even achieved that level of commercial significance. So it's basically "less RISC than it used to be" Arm, and "more RISC than it used to be" x86. But there is one notable CISC still out there: IBM's mainframe z/Architecture. Might not sell a lot of units, but it's still pretty important commercially.
- yellowapple 7y ago> SPARC lives on only in radiation-hardened form for the European space agency. Worth noting that POWER similarly lives on in radiation-hardened form for NASA; the RAD750 (and its predecessor, the RAD3000) both have a long history of interplanetary use. MIPS also sees some use here, too; for example, the MIPS-based Mongoose-V is what New Horizons uses, and the KOMDIV-32 ostensibly is designed for Russian spacecraft use (but I don't know of any specific examples).
- kevin_thibedeau 7y agoThey're all RISC.