3 ms·

Aaaah, the Power ISA... If you want to "rotate left immediate speculatively if condition matches additionally push sign bit on the stack and zero extend the nex

Aaaah, the Power ISA... If you want to "rotate left immediate speculatively if condition matches additionally push sign bit on the stack and zero extend the next register unless it has an odd value", this is the most likely architecture to do that for you ;-) At least its the one I most often need to take a look at the manual what slxwimzus (or something like that) exactly does when looking at disassembly. Of course luckily most compilers don't do the freaky stuff, so I'm probably quite lucky :)

etaioinshrdlu 6y ago
""""Reduced"""" Instruction Set Computer?
- yjftsjthsd-h 6y ago
  From the Wikipedia page for RISC: """ Instruction set philosophy A common misunderstanding of the phrase "reduced instruction set computer" is the mistaken idea that instructions are simply eliminated, resulting in a smaller set of instructions.[2] In fact, over the years, RISC instruction sets have grown in size, and today many of them have a larger set of instructions than many CISC CPUs. [Snip] The term "reduced" in that phrase was intended to describe the fact that the amount of work any single instruction accomplishes is reduced—at most a single data memory cycle—compared to the "complex instructions" of CISC CPUs that may require dozens of data memory cycles in order to execute a single instruction.[23] In particular, RISC processors typically have separate instructions for I/O and data processing.[citation needed] The term load/store architecture is sometimes preferred. """
  - a1369209993 6y ago
    IOW, it's a Set of Reduced Instructions rather than a Reduced Set of Instructions? (aka (RI)SC rather than R(IS)C?)
perl4ever 6y ago
Copying something quoted on HN ~4yrs ago: "IBM has a well-known disdain for vowels, and basically refuses to use them for mnemonics (they were called on this, and did "eieio" as an instruction just to try to make up for it)." - Linus Torvalds, 2009
- archi42 6y ago
  I could swear it also has a `mkitso` mnemonic.
  - perl4ever 6y ago
    Don't think so. There is "stfsux" though. I like rlwinm which takes five arguments. It can do so many things there are like 12 alternative mnemonics for simplicity. https://www.ibm.com/support/knowledgecenter/en/ssw_aix_72/assembler/idalangref_32bit_rtate_shift.html https://www.ibm.com/support/knowledgecenter/en/ssw_aix_72/as...
Someone 6y ago
https://developer.ibm.com/technologies/linux/articles/l-ppc/ https://developer.ibm.com/technologies/linux/articles/l-ppc/: “The rotate instructions (like the rlicr seen here) are notoriously complicated, and having jokingly been called Turing-complete”

etaioinshrdlu 6y ago

""""Reduced"""" Instruction Set Computer?

yjftsjthsd-h 6y ago
From the Wikipedia page for RISC: """ Instruction set philosophy A common misunderstanding of the phrase "reduced instruction set computer" is the mistaken idea that instructions are simply eliminated, resulting in a smaller set of instructions.[2] In fact, over the years, RISC instruction sets have grown in size, and today many of them have a larger set of instructions than many CISC CPUs. [Snip] The term "reduced" in that phrase was intended to describe the fact that the amount of work any single instruction accomplishes is reduced—at most a single data memory cycle—compared to the "complex instructions" of CISC CPUs that may require dozens of data memory cycles in order to execute a single instruction.[23] In particular, RISC processors typically have separate instructions for I/O and data processing.[citation needed] The term load/store architecture is sometimes preferred. """
- a1369209993 6y ago
  IOW, it's a Set of Reduced Instructions rather than a Reduced Set of Instructions? (aka (RI)SC rather than R(IS)C?)

perl4ever 6y ago

Copying something quoted on HN ~4yrs ago: "IBM has a well-known disdain for vowels, and basically refuses to use them for mnemonics (they were called on this, and did "eieio" as an instruction just to try to make up for it)." - Linus Torvalds, 2009

archi42 6y ago
I could swear it also has a `mkitso` mnemonic.
- perl4ever 6y ago
  Don't think so. There is "stfsux" though. I like rlwinm which takes five arguments. It can do so many things there are like 12 alternative mnemonics for simplicity. https://www.ibm.com/support/knowledgecenter/en/ssw_aix_72/assembler/idalangref_32bit_rtate_shift.html https://www.ibm.com/support/knowledgecenter/en/ssw_aix_72/as...

Someone 6y ago

https://developer.ibm.com/technologies/linux/articles/l-ppc/ https://developer.ibm.com/technologies/linux/articles/l-ppc/: “The rotate instructions (like the rlicr seen here) are notoriously complicated, and having jokingly been called Turing-complete”