PowerPC Tutorial

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Chapter 33: Conclusion, What is to be done?

Welp that's it for the PowerPC tutorial. Congratulations! There are still some things left on the table to learn. At this point though, you are trained enough to read professional/official PowerPC Manuals. What we didn't discuss....

  1. Deeper Dive into Exceptions. Writing out custom Exception Handlers, Handling interrupts, Using the Decrementer.
  2. The Time Base
  3. Writing out an entire Boot/Reset Code (we've only covered BATs and Page Tables)
  4. Deeper dive into Float mechanics (FPSCR, handling NaN's, etc)
  5. Instruction Pipeline tutorial (not just a quick intro)
  6. Writing faster code
  7. Using the Performance Monitor to test performance of code (most PPC chips have this tool)

I'll briefly go over faster code. Here's some basic code below that you are familiar with.

#Conventional Code
lis r3, 0x8000
lwz r3, 0x1500 (r3)
li r4, 1
lis r12, 0x8045
ori r12, r12, 0x50CC
mtctr r12
bctrl

Now here's the same code but written in a way to be faster.

#Faster Code
lis r12, 0x8045
lis r5, 0x8000
ori r12, r12, 0x50CC
ori r5, r5, 0x1500
li r4, 1
dcbt r0, r5
lwz r3, 0 (r5)
mtctr r12
bctrl

The below is code is faster because....

If you want to continue further into your PowerPC journey, I have some homework for you. Download this zip file HERE. Inside this zip is multiple PowerPC manuals. I want you to read the following...

  1. PowerPC Microprocessor Family: The Programming Environments (Yes it's over 800 pages....) This is what I call the "PowerPC Bible".
  2. Broadway Manual (Chapter 6 *ONLY*) Goes into deeper discussion of the Instruction Pipeline. The Manual is for the Broadway chip, but can be applied for most other 32-bit PPC chips.
  3. PowerPC Compiler Writer's Guide. It's gives key lessons and tricks about writing faster code (suitable for Compilers). If you are familiar with C, there are many C-to-PPC code examples.

If you are still confused about the basics of writing fast code, then you should YouTube/Google the following..

A quick search brings up plenty of videos that will teach the above concepts (in a general sense that can apply to multiple Assembly Languages, not just PPC).

Cheers~
- Vega

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