13 ms·

What is the point in copying hex values?

gravypod 10y ago
To the outside world of non-CS people the concept of a processor is magic. It is in a sense still magical to me but I can see that a processor is just a complex state machine that takes in numbers and spits out numbers. Saying that without really experiancing it means nothing and I cannot put into words the value of understanding this. It makes so many previously unaprochable tasks much less daunting. Copying in hex values will give the student many important skills. At first they will learn to recognize errors in the hex by identifying opcodes for the instruction set you are using. IIRC 0xEB amd 0xEA is a jmp. Secondly they will understand how the assebmly is turned into code executable by the CPU. It's not magic it's just a simple map operation taking the text from the assembly and 1:1 mapping it (in most cases) to opcodes. Knowing the opcodes by heart is nice for debugging and decompiling/reverse engineering code. It's fun to do and a really important skill, in my book, for anyone doing computer science in the real world (and if you're paying >10k/semester at college you should know how to do it!). Getting a feal for what is really happening under the hood, just numbers being read, run, and repeat will help you understand how to write a compiler. Again, I can tell you all this and give you a chart to memorize and say "THIS WILL HELP YOU" or I can let you natrually tackel your tasks and allow you, on your own time, to find out what helps you get the job done. The one thing that isn't negotiable is giving you tasks that incrementally will challange you but not scare you away. What is negotiable is how these are presented. I feel they should be unseen tasks hidden undernethe something that looks like something else to the student.
- witty_username 10y ago
  > It's not magic it's just a simple map operation taking the text from the assembly and 1:1 mapping it (in most cases) to opcodes. Maybe in the Z80, but in modern x86 the instructions are broken down into micro ops and also pipelined (multiple pipelines, even). > Knowing the opcodes by heart is nice for debugging and decompiling/reverse engineering code. It's fun to do and a really important skill, in my book, for anyone doing computer science in the real world (and if you're paying >10k/semester at college you should know how to do it!). Why would you need to memorize hex opcodes for CS in the real world? I'll just use objdump or my favorite disassembler (even gdb can print instructions). > will help you understand how to write a compiler. Not sure how it will help one understand.
  - gravypod 10y ago
    You've taken assembly, transformed it into opcodes in paper, and then manually typed that into a file. The instructor should ask "Is there a way that you can do this that would allow you to avoid doing this?" You've now been - Told there's a better way - Want to stop doing this as it's error prone and boring - Know every step of binary construction by heart That's the perfect starting ground for exploring cs in my book.

To the outside world of non-CS people the concept of a processor is magic. It is in a sense still magical to me but I can see that a processor is just a complex state machine that takes in numbers and spits out numbers. Saying that without really experiancing it means nothing and I cannot put into words the value of understanding this. It makes so many previously unaprochable tasks much less daunting. Copying in hex values will give the student many important skills. At first they will learn to recognize errors in the hex by identifying opcodes for the instruction set you are using. IIRC 0xEB amd 0xEA is a jmp. Secondly they will understand how the assebmly is turned into code executable by the CPU. It's not magic it's just a simple map operation taking the text from the assembly and 1:1 mapping it (in most cases) to opcodes. Knowing the opcodes by heart is nice for debugging and decompiling/reverse engineering code. It's fun to do and a really important skill, in my book, for anyone doing computer science in the real world (and if you're paying >10k/semester at college you should know how to do it!). Getting a feal for what is really happening under the hood, just numbers being read, run, and repeat will help you understand how to write a compiler. Again, I can tell you all this and give you a chart to memorize and say "THIS WILL HELP YOU" or I can let you natrually tackel your tasks and allow you, on your own time, to find out what helps you get the job done. The one thing that isn't negotiable is giving you tasks that incrementally will challange you but not scare you away. What is negotiable is how these are presented. I feel they should be unseen tasks hidden undernethe something that looks like something else to the student.

witty_username 10y ago
> It's not magic it's just a simple map operation taking the text from the assembly and 1:1 mapping it (in most cases) to opcodes. Maybe in the Z80, but in modern x86 the instructions are broken down into micro ops and also pipelined (multiple pipelines, even). > Knowing the opcodes by heart is nice for debugging and decompiling/reverse engineering code. It's fun to do and a really important skill, in my book, for anyone doing computer science in the real world (and if you're paying >10k/semester at college you should know how to do it!). Why would you need to memorize hex opcodes for CS in the real world? I'll just use objdump or my favorite disassembler (even gdb can print instructions). > will help you understand how to write a compiler. Not sure how it will help one understand.
- gravypod 10y ago
  You've taken assembly, transformed it into opcodes in paper, and then manually typed that into a file. The instructor should ask "Is there a way that you can do this that would allow you to avoid doing this?" You've now been - Told there's a better way - Want to stop doing this as it's error prone and boring - Know every step of binary construction by heart That's the perfect starting ground for exploring cs in my book.