Just yesterday I ran into some chucklehead here on Lemmy that had convinced themselves that the average person would interpret “crypto” to mean SSL rather than cryptocurrency.
I had one last week here on claiming the average person could feed themselves for years by growing cherry tomatoes from 6 tiny plants. Bro is supposed to be a big-time agricultural bigwig
Makes sense. Human beings don’t actually need proteins or fats.
At least dead ones dont
That seems like the opposite problem
You mean things like Bigfoot?
Holy shit that was weird.
I saw that thread, I think. Or the same person in another thread talking about the same thing.
All the code I know is stackoverflow search results.
of course nods along
I feel attacked.
I mean who hasnt watched “Assembly Language in 100 seconds” by Fireship
Just looked this up and subscribed to the channel.
I mean I’m only missing int3
I didn’t even know they released int2
I think it is 0xCC, or in long form 0xCD03
NOP is $EA, of course, and… um…
…sorry, I’m just a Commodore 64 scrub, I don’t know nothing about this high and mighty Intel 8086 nonsense.
[looking up]
…it’s 0x90 on IA-32? WHAT? Someone told me every processor used 0xEA because that was commonly agreed and readily apparent. …guess I was wrong
My daughter told me the other day, “I bet I could figure out a Commodore 64 if I had one.”
Good luck figuring out LOAD “*”,8,1 by yourself, kid.
Literally every game manual comes with instructions to do
LOAD "*",8,1. (oh, did I say “manual”? Instruction card. Yeaaaah, the minimal instuction stuff isn’t new, kids.) Everyone and their dog figured it out. If there was any command anyone knew, it was that. …only to be topped bySHIFT+RUN/STOPfor initiating tape load (which you could just do by typing in, you know,LOAD).Know what else we did when we were kids? WE ASKED AROUND. If you don’t tell your kid how this thing works, you’re making things worse, to be frank. I mean, if some random kid came up to me and asked how to load a C64 game, I’d give them a goddamn lecture free of charge.
She meant she could figure it out just playing around with it, not reading a manual or asking around. I told her she’d have to read a manual.
Erm I might be showing my inexperience here.
Is there no equivalent to
man LOADin the commodore world? Or even justhelp?
As a bytecode tinkerer, I’d say considering NOP to be global knowledge is a slippery slope.
Might want a sled and a ROPe to have a smooth descent
Now I want to know what int3 does.
https://en.wikipedia.org/wiki/INT_(x86_instruction) (scroll down to INT3)
https://stackoverflow.com/a/61946177
The TL;DR is that it’s used by debuggers to set a breakpoint in code.
For example, if you’re familiar with gdb, one of the simplest ways to make code stop executing at a particular point in the code is to add a breakpoint there.
Gdb replaces the instruction at the breakpoint with 0xCC, which happens to be the opcode for INT 3 — generate interrupt 3. The CPU then generates interrupt 3, the kernel’s interrupt handler sends a signal (SIGTRAP) to the debugger, and thus the debugger will know it’s meant to start a debugging loop there.
Hey thank you!
Not what I thought it was for sure 😃
How does it work if an instruction gets replaced by the INT3 though?
Excellent question!
Before replacing the instruction with INT 3, the debugger keeps a note of what instruction was at that point in the code. When the CPU encounters INT 3, it hands control to the debugger.
When the debugging operations are done, the debugger replaces the INT 3 with the original instruction and makes the instruction pointer go back one step, thereby ensuring that the original instruction is executed.
Whoo that seems complicated, I mean you akready compile a debug version.
Thanks for the explanation!
The debug version you compile doesn’t affect the code; it just stores more information about symbols. The whole shtick about the debugger replacing instructions with INT3 still happens.
You can validate that the code isn’t affected yourself by running objdump on two binaries, one compiled with debug symbols and one without. Otherwise if you’re lazy (like me 😄):
https://stackoverflow.com/a/8676610
And for completeness: https://gcc.gnu.org/onlinedocs/gcc-14.1.0/gcc/Debugging-Options.html
Is there any situation where you’d want to remember the opcodes? Disassemblers should give you user-friendly assembly code, without any need to look at the raw numbers. Maybe it’s useful to remember which instructions are pseudo instructions (so you know stuff like
jz(jump if zero) being the same asje(jump if equal) making it easier to understand the disassembly), but I don’t think you need to remember the opcode numbers for that.The important thing is to be important. Engineering has to deal with teammates that don’t have these problems, so they equalize.
You’re sixteen, you’re beautiful, I’m under arrest
