4 ms·
any reasons to NOT using x86_64 and forget about ia32? Netbooks? They're obsolete. ARM/Android will be everywhere next year. ^_^
by schiptsov 15y ago
any reasons to NOT using x86_64 and forget about ia32? Netbooks? They're obsolete. ARM/Android will be everywhere next year. ^_^
- jwatte 15y agoX86_64 is also bizarre, with mode switch as partt of jump, register aliasing, etc.
- psykotic 15y agoMy least favorite part when reading and writing x64 code has to be the calling conventions.
- mansr 15y agoThere is nothing bizarre about implementing mode switching as part of a jump instruction. Every CPU I know of with more than one mode implements switching with some kind of jump instruction.
- psykotic 15y agoI agree it isn't bizarre. But... > Every CPU I know of with more than one mode implements switching with some kind of jump instruction. So you don't know x86? You enter protected mode by manipulating the cr0 register.
- mansr 15y agoSo what jwatte said is wrong? I don't know such details about x86. I was thinking mainly of ARM and MIPS.
- psykotic 15y agoNo, he was referring to the 32-bit to 64-bit mode switch. I was talking about entering 32-bit protected mode from real mode for the first time, typically right after boot-up. As another posted mentioned, once you're in protected mode, you can go back to "fake" real mode (e.g. an MS DOS program running on Windows) with a segment descriptor based jump, which is consistent with the manner of x64's mode switching.
- dfox 15y agoBut after entering 386-style protected mode or amd64's long mode you can switch between different modes by far jumps to specially crafted descriptors / selectors (and at least in 32 bit protected mode you can trigger various documented semi-magical behavior by that). So it's consistent.
- psykotic 15y agoUnfortunately, there are tons of people out there still running 32-bit Windows. Microsoft had a chance to cut the cord with Vista and 7 but they blew it.