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https://j-core.org/ https://j-core.org/ "What is this processor? The SuperH processor is a Japanese design developed by Hitachi in the late 1990's. As a second
by initramfs 2y ago
https://j-core.org/ https://j-core.org/
"What is this processor?
The SuperH processor is a Japanese design developed by Hitachi in the late 1990's. As a second generation hybrid RISC design it was easier for compilers to generate good code for than earlier RISC chips, and it recaptured much of the code density of earlier CISC designs by using fixed length 16 bit instructions (with 32 bit register size and address space), using microcoding to allow some instructions to perform multiple clock cycles of work. (Earlier pure risc designs used one instruction per clock cycle even when that served no purpose but to make the code bigger and exhaust the encoding space.)
Hitachi developed 4 generations of SuperH. SH2 made it to the United states in the Sega Saturn game console, and SH4 powered the Sega Dreamcast. They were also widely used in areas outside the US cosumer market, such as the japanese automative industry.
But during the height of SuperH's development, the 1997 asian economic crisis caused Hitachi to tighten its belt, eventually partnering with Mitsubishi to spin off its microprocessor division into a new company called "Renesas". This new company did not inherit the Hitachi engineers who had designed SuperH, and Renesas' own attempts at further development on SuperH didn't even interest enough customers for the result to go ito production. Eventually Renesas moved on to new designs it had developed entirely in-house, and SuperH receded in importance to them... until the patents expired."
- kjs3 2y agoThe SH4 is a really interesting chip, with some embryonic vector instruction. There are also SH variants with a DSP bolted on.
- mikepurvis 2y agoInteresting point of history— the H8 processor is the MCU that powers the original Lego Mindstorms RCX. In high school I wrote some assembly language for it when making a robot that ran on BrickOS: https://en.m.wikipedia.org/wiki/BrickOS https://en.m.wikipedia.org/wiki/BrickOS
- kn100 2y agoa slightly different (but close enough) Hitachi CPU also powered the Cybiko - a wacky games console few have heard of. I tried writing a disassembler for that particular cpu a while back. Was an interesting platform and oh man the documentation at least to me was gorgeous: github.com/kn100/cybemu/
- dagmx 2y agoLink to the cybiko https://en.wikipedia.org/wiki/Cybiko https://en.wikipedia.org/wiki/Cybiko That is a really wild design
- phs318u 2y agoLove it! “The concept for the device emerged from social research conducted in six countries, which identified a need for digital communication among youth. … a radio protocol was patented. This protocol allowed up to 3,000 Cybiko devices to form a network without using auxiliary stations.” Fascinating!
- cpach 2y agoWow. That’s basically a smartphone!? Just way ahead of its time.
- hfgjbcgjbvg 2y agoApple might as well do this and cut out the carriers.
- xattt 2y agoIs this what the Thread radios in all Apple devices are hiding?
- teruakohatu 2y agoSadly Thread is 2.4ghz rather than the much lower and longer range Lora frequencies. It’s designed to be used within the home and between homes.
- immibis 2y agoMy CASIO graphics calculator from high school also uses a SuperH.
- voidbert 2y agoAnd interestingly for a graphing calculator, it lacks an FPU, and all floating point math has to be done in software.
- epcoa 2y agoNot particularly unique at all. Handheld graphing calculators typically were not intended for use where hardware floating point was necessary. TI calculators historically used the Z80, no FPU. Earlier HP calculators did use a custom BCD based (not IEEE954) floating point ISA, but these are still slower than just about any processor in the past 30 years doing software floating point. They didn’t have any hardware multiply or divide for one, this is not an FPU in the modern sense people envision. And later on the HP used common ARMv5 based processors with emulation. None of these ARM processors had hardware floating point. Same with later TI calculators that were 68k and then ARM based. The HP Prime G2 released in 2018 is about the only mainstream device that happens to have hardware FP, and that’s for a device more touted for CAS features. The FPU is more just something that comes for free with the commodity SoC chosen.
- rbanffy 2y ago> None of these ARM processors had hardware floating point More importantly, IEEE 754 floating point ISA is not great for calculators - they don’t require the speed a personal computer does, and calculators work hard to hide the fact numbers such as 0.45 can’t be represented as IEEE 754 floats.
- immibis 2y agoIt uses decimal floating point, so that's no worry.
- chaosite 2y agoIn popular culture, the Hitachi H8 microprocessor was referenced in the song Space Dementia by Muse. > Q - "What does "H Eight" mean?" > Matt [Bellamy]: Using a microcomputer (Hitachi H8 / 3048F) which can be built into the industrialmachines, you can learn and understand the inputs /outputs of the microcomputer as a basis of robot control and conduct theexperiments by C-language for steppingmotor control, servomotor control (PWM control) and serial communication. H8 model, a 16-bit microcomputer consists of 32-bit registers, has a flash ROM of 128KB, a RAM of 4KB (SRAM) with external extension of 128KB and 78 I/O terminals with the built-in A/D and D/Aconverters. H8 is a microcomputer usually built into a TV, VTR, mobile-phone and car navigator. Since it has ample I/O terminals, H8 microcomputer is also used as a brain of a small robot. [0] - https://web.archive.org/web/20160406073458/https://www.microcuts.net/uk/news/archives/06032003-interview.php https://web.archive.org/web/20160406073458/https://www.micro...
- Tor3 2y agoThere was a SuperH in my parents' Panasonic TV - I found the GPL license and kernel info deep in the menu system.
- sspiff 2y agoI had a SuperH 3 powered HP Jornada that I ran Linux and NetBSD on back in the day. Not particularly fast, but power efficiency was off the charts, even when compared to the many contemporary ARM and MIPS based devices of the time. Or at least that's how my nostalgic memories think of it. It was really fun to have a pocketable laptop back in those days for me (baggy pants required). Good times.
- wslh 2y agoI would love to see a modern device with a similar form factor to the classic PDAs. After some searching, I found a few options, but none of them are quite the same. Here's what I came across [1], [2], and potentially [3]. Does anyone know of other devices that come closer to the original clamshell PDA design? [1] https://www.gpd.hk/gpdpocket https://www.gpd.hk/gpdpocket [2] https://store.planetcom.co.uk/products/astro-slide https://store.planetcom.co.uk/products/astro-slide [3] https://pine64.org/documentation/Phone_Accessories/Keyboard/ https://pine64.org/documentation/Phone_Accessories/Keyboard/
- tm0 2y agoThough about six years old, the Gemini PDA (from the same folks who make the Astro Slide) is likely the most modern device with the classic clamshell PDA form factor. https://store.planetcom.co.uk/products/gemini-pda-wifi-only https://store.planetcom.co.uk/products/gemini-pda-wifi-only https://www.youtube.com/watch?v=7_TybtULQVo https://www.youtube.com/watch?v=7_TybtULQVo (interview with the designer, who was also one of the designers for the Psion PDA) If you are allowing a bit more modernity, they have the Cosmo Communicator, which has a screen on the outside. https://store.planetcom.co.uk/collections/devices/products/cosmo-communicator https://store.planetcom.co.uk/collections/devices/products/c...
- RajT88 2y agoI have owned both the astro slide and the Gemini PDA. Gemini is great: get one. Astro slide not so much.
- hulitu 2y ago> spin off its microprocessor division into a new company called "Renesas". This new company did not inherit the Hitachi engineers who had designed SuperH This explaines why Renesas' products are so bad and why the datasheets are terrible.
- joezydeco 2y agoI tried to evaluate their intro Linux processor (RZ/A) a while back and the amount of support we got from the factory was dismal. I got an FAE to confess that the two factions (Hitachi vs NEC) didn't get along. They have a bread-and-butter product line in the RL78 but we dropped the idea of using them for anything else.
- publicmail 2y agoThe ECU in my 350z also used a SuperH CPU - I think SH2?
- asveikau 2y ago> developed by Hitachi in the late 1990's. I remember hearing about SuperH in the early 90s. Wikipedia says 1992. > in the Sega Saturn game console, Wasn't that around 1995? Already too early for "late" 1990s.
- giantrobot 2y agoThe Saturn development was started around 1992 and was released in Japan in 1994.
- farmdve 2y agoI have done extensive reverse engineering of SH2 firmwares, at first I didn't like it, but then found it elegant.
- phire 2y ago> Hitachi developed 4 generations of SuperH. Technically it's only three generations, as the SH-1 and SH-2 were launched at the same time. The SH-1 was a stripped down basic model, missing a few instructions like 32-bit multiplication, while the SH-2 had everything. The Sega Saturn had two SH-2s for the main CPU, and one SH-1 as a CDROM controller. it also had a 68EC000 for the sound subsystem... and a DSP.... Too many CPUs.
- DaoVeles 2y agoI only ever had a very brief hands on time with SuperH based systems (excluding the excessive amount of Saturn/Dreamcast play time). They seemed to have efficiency as their very core goal. So while they were not the fastest processors around, they squeezed out every little drop from what they had to work with.