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  3. Saw a blog post titled "How many registers does an x86-64 CPU have?" and my immediate thought was "it's impossible to know and a sin to ask".

Saw a blog post titled "How many registers does an x86-64 CPU have?" and my immediate thought was "it's impossible to know and a sin to ask".

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  • ryanc@infosec.exchangeR ryanc@infosec.exchange

    Saw a blog post titled "How many registers does an x86-64 CPU have?" and my immediate thought was "it's impossible to know and a sin to ask".

    If you think the answer is 16, by the way, no it is not.

    hp@mastodon.tmm.cxH This user is from outside of this forum
    hp@mastodon.tmm.cxH This user is from outside of this forum
    hp@mastodon.tmm.cx
    wrote last edited by
    #19

    @ryanc between 40 and transistor count / 3.

    That's accurate, but not very precise. 😀

    1 Reply Last reply
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    • nspace@infosec.exchangeN nspace@infosec.exchange

      @gsuberland @ryanc we have microcode for amd too 😛 and it works on the newest cpus unlike on intel. there are a lot of internal registes you can access only through microcode

      gsuberland@chaos.socialG This user is from outside of this forum
      gsuberland@chaos.socialG This user is from outside of this forum
      gsuberland@chaos.social
      wrote last edited by
      #20

      @nspace @ryanc ah neat. I haven't read through the AMD stuff yet

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      • ryanc@infosec.exchangeR ryanc@infosec.exchange

        Saw a blog post titled "How many registers does an x86-64 CPU have?" and my immediate thought was "it's impossible to know and a sin to ask".

        If you think the answer is 16, by the way, no it is not.

        bitchboss@marcella.masto.hostB This user is from outside of this forum
        bitchboss@marcella.masto.hostB This user is from outside of this forum
        bitchboss@marcella.masto.host
        wrote last edited by
        #21

        @ryanc

        A whole bunch of registers. If you run out of it, You might considder to stop using Macro Assembler and write GWBasic programs...

        RAX, RBX, RCX, RDX, EAX, EBX, ECX, EDX, RDI, RSI, RBP, RSP, EDI, ESI, EBP, ESP, R8-R15, CS, DS, ES, FS, GS, SS, RIP, EIP, RFLAGS, EFLAGS, CR0-CR4, DR0-DR7, MSRs, SIMD, XMM0-XMM15, YMM0-YMM15, ZMM0-ZMM31, MM0--MM7,
        ST0-ST7, MXCSR.

        dascandy@infosec.exchangeD 1 Reply Last reply
        0
        • R relay@relay.publicsquare.global shared this topic
        • ryanc@infosec.exchangeR ryanc@infosec.exchange

          Saw a blog post titled "How many registers does an x86-64 CPU have?" and my immediate thought was "it's impossible to know and a sin to ask".

          If you think the answer is 16, by the way, no it is not.

          timwardcam@c.imT This user is from outside of this forum
          timwardcam@c.imT This user is from outside of this forum
          timwardcam@c.im
          wrote last edited by
          #22

          @ryanc Even for a Z80 it's not a trivial answer. (Yes I do know someone who wrote some code that used the R register.)

          lp0_on_fire@social.linux.pizzaL 1 Reply Last reply
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          • ryanc@infosec.exchangeR ryanc@infosec.exchange

            Saw a blog post titled "How many registers does an x86-64 CPU have?" and my immediate thought was "it's impossible to know and a sin to ask".

            If you think the answer is 16, by the way, no it is not.

            halcy@icosahedron.websiteH This user is from outside of this forum
            halcy@icosahedron.websiteH This user is from outside of this forum
            halcy@icosahedron.website
            wrote last edited by
            #23

            @ryanc oh, that’s easy, actually. The answer is precisely one less than whatever the ideal number for your workload would be.

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            • ryanc@infosec.exchangeR ryanc@infosec.exchange

              Saw a blog post titled "How many registers does an x86-64 CPU have?" and my immediate thought was "it's impossible to know and a sin to ask".

              If you think the answer is 16, by the way, no it is not.

              indigoviolet@tech.lgbtI This user is from outside of this forum
              indigoviolet@tech.lgbtI This user is from outside of this forum
              indigoviolet@tech.lgbt
              wrote last edited by
              #24

              @ryanc (xkcd 2867)

              1 Reply Last reply
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              • javierg@mstdn.socialJ javierg@mstdn.social

                @ryanc
                Long ago, I was starting to understand register renaming (the phrase "register file" gave me existencial doubts), and then they came with hyperthreading...
                Now I feel CPU architecture is purely a spectator sport.

                arrjay@tacobelllabs.netA This user is from outside of this forum
                arrjay@tacobelllabs.netA This user is from outside of this forum
                arrjay@tacobelllabs.net
                wrote last edited by
                #25

                @javierg @ryanc register usage is certainly a speculative sport

                1 Reply Last reply
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                • ryanc@infosec.exchangeR ryanc@infosec.exchange

                  Saw a blog post titled "How many registers does an x86-64 CPU have?" and my immediate thought was "it's impossible to know and a sin to ask".

                  If you think the answer is 16, by the way, no it is not.

                  gunstick@mastodon.opencloud.luG This user is from outside of this forum
                  gunstick@mastodon.opencloud.luG This user is from outside of this forum
                  gunstick@mastodon.opencloud.lu
                  wrote last edited by
                  #26

                  @ryanc easier question:
                  How many registers does the Motorola 68000 have?
                  It is also not 16.

                  1 Reply Last reply
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                  • bitchboss@marcella.masto.hostB bitchboss@marcella.masto.host

                    @ryanc

                    A whole bunch of registers. If you run out of it, You might considder to stop using Macro Assembler and write GWBasic programs...

                    RAX, RBX, RCX, RDX, EAX, EBX, ECX, EDX, RDI, RSI, RBP, RSP, EDI, ESI, EBP, ESP, R8-R15, CS, DS, ES, FS, GS, SS, RIP, EIP, RFLAGS, EFLAGS, CR0-CR4, DR0-DR7, MSRs, SIMD, XMM0-XMM15, YMM0-YMM15, ZMM0-ZMM31, MM0--MM7,
                    ST0-ST7, MXCSR.

                    dascandy@infosec.exchangeD This user is from outside of this forum
                    dascandy@infosec.exchangeD This user is from outside of this forum
                    dascandy@infosec.exchange
                    wrote last edited by
                    #27

                    @ryanc @bitchboss you forgot ah, al, ch, cl, dh, dl, bh, bl, dil, sil, spl and bpl. And of course r8l, r8w etc.

                    bitchboss@marcella.masto.hostB 1 Reply Last reply
                    0
                    • hp@mastodon.tmm.cxH This user is from outside of this forum
                      hp@mastodon.tmm.cxH This user is from outside of this forum
                      hp@mastodon.tmm.cx
                      wrote last edited by
                      #28

                      @kaye @ryanc I thought it the most important rule of CPU architectures was to be a PDP-11 and have fun.

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                      • dascandy@infosec.exchangeD dascandy@infosec.exchange

                        @ryanc @bitchboss you forgot ah, al, ch, cl, dh, dl, bh, bl, dil, sil, spl and bpl. And of course r8l, r8w etc.

                        bitchboss@marcella.masto.hostB This user is from outside of this forum
                        bitchboss@marcella.masto.hostB This user is from outside of this forum
                        bitchboss@marcella.masto.host
                        wrote last edited by
                        #29

                        @dascandy @ryanc

                        Damn... Are those 8/16 bitters still in use?

                        gsuberland@chaos.socialG 1 Reply Last reply
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                        • ryanc@infosec.exchangeR ryanc@infosec.exchange

                          Saw a blog post titled "How many registers does an x86-64 CPU have?" and my immediate thought was "it's impossible to know and a sin to ask".

                          If you think the answer is 16, by the way, no it is not.

                          keinna@plasmatrap.comK This user is from outside of this forum
                          keinna@plasmatrap.comK This user is from outside of this forum
                          keinna@plasmatrap.com
                          wrote last edited by
                          #30

                          @ryanc@infosec.exchange more than one

                          1 Reply Last reply
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                          • ryanc@infosec.exchangeR ryanc@infosec.exchange

                            Saw a blog post titled "How many registers does an x86-64 CPU have?" and my immediate thought was "it's impossible to know and a sin to ask".

                            If you think the answer is 16, by the way, no it is not.

                            dalias@hachyderm.ioD This user is from outside of this forum
                            dalias@hachyderm.ioD This user is from outside of this forum
                            dalias@hachyderm.io
                            wrote last edited by
                            #31

                            @ryanc It depends a lot on what you mean by registers and which execution domain you're talking about.

                            ryanc@infosec.exchangeR 1 Reply Last reply
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                            • nspace@infosec.exchangeN nspace@infosec.exchange

                              @gsuberland @ryanc we have microcode for amd too 😛 and it works on the newest cpus unlike on intel. there are a lot of internal registes you can access only through microcode

                              pixx@merveilles.townP This user is from outside of this forum
                              pixx@merveilles.townP This user is from outside of this forum
                              pixx@merveilles.town
                              wrote last edited by
                              #32

                              @nspace
                              Ooh, links?
                              @gsuberland @ryanc

                              nspace@infosec.exchangeN 1 Reply Last reply
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                              • dalias@hachyderm.ioD dalias@hachyderm.io

                                @ryanc It depends a lot on what you mean by registers and which execution domain you're talking about.

                                ryanc@infosec.exchangeR This user is from outside of this forum
                                ryanc@infosec.exchangeR This user is from outside of this forum
                                ryanc@infosec.exchange
                                wrote last edited by
                                #33

                                @dalias yes

                                1 Reply Last reply
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                                • ryanc@infosec.exchangeR ryanc@infosec.exchange

                                  Saw a blog post titled "How many registers does an x86-64 CPU have?" and my immediate thought was "it's impossible to know and a sin to ask".

                                  If you think the answer is 16, by the way, no it is not.

                                  kentenmakto@mastodon.ieK This user is from outside of this forum
                                  kentenmakto@mastodon.ieK This user is from outside of this forum
                                  kentenmakto@mastodon.ie
                                  wrote last edited by
                                  #34

                                  @ryanc Related: I grew up thinking the 6502 had three registers.

                                  Then I saw someone say X and Y weren't registers at all.

                                  Then I saw someone else say the first 256 bytes of RAM *were* registers.

                                  1 Reply Last reply
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                                  • ryanc@infosec.exchangeR ryanc@infosec.exchange

                                    Saw a blog post titled "How many registers does an x86-64 CPU have?" and my immediate thought was "it's impossible to know and a sin to ask".

                                    If you think the answer is 16, by the way, no it is not.

                                    stompyrobot@mastodon.gamedev.placeS This user is from outside of this forum
                                    stompyrobot@mastodon.gamedev.placeS This user is from outside of this forum
                                    stompyrobot@mastodon.gamedev.place
                                    wrote last edited by
                                    #35

                                    @ryanc
                                    You *can* talk about "architectural registers" though. But even there, there are a bunch of special purpose registers, so what counts as a "register?"

                                    1 Reply Last reply
                                    0
                                    • ryanc@infosec.exchangeR ryanc@infosec.exchange

                                      Saw a blog post titled "How many registers does an x86-64 CPU have?" and my immediate thought was "it's impossible to know and a sin to ask".

                                      If you think the answer is 16, by the way, no it is not.

                                      compod@mastodon.socialC This user is from outside of this forum
                                      compod@mastodon.socialC This user is from outside of this forum
                                      compod@mastodon.social
                                      wrote last edited by
                                      #36

                                      @ryanc having looked into that blog post: complicated. Very complicated. (To quote the Doctor)

                                      1 Reply Last reply
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                                      • bitchboss@marcella.masto.hostB bitchboss@marcella.masto.host

                                        @dascandy @ryanc

                                        Damn... Are those 8/16 bitters still in use?

                                        gsuberland@chaos.socialG This user is from outside of this forum
                                        gsuberland@chaos.socialG This user is from outside of this forum
                                        gsuberland@chaos.social
                                        wrote last edited by
                                        #37

                                        @bitchboss @dascandy @ryanc yup, you even get them for the extended GPRs in x64

                                        dascandy@infosec.exchangeD 1 Reply Last reply
                                        0
                                        • ryanc@infosec.exchangeR ryanc@infosec.exchange

                                          Saw a blog post titled "How many registers does an x86-64 CPU have?" and my immediate thought was "it's impossible to know and a sin to ask".

                                          If you think the answer is 16, by the way, no it is not.

                                          israajamal@mastodon.socialI This user is from outside of this forum
                                          israajamal@mastodon.socialI This user is from outside of this forum
                                          israajamal@mastodon.social
                                          wrote last edited by
                                          #38

                                          @ryanc please help me and support me 🇵🇸 #freepalestine

                                          1 Reply Last reply
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