# Architectural Difference between PowerPc and Intel Processors



## abubakar_119 (Apr 5, 2006)

I was thinking why we can't install operating system XP on power pc based computer, otherwise its possibel in intel base Macintosh computers.
I asked the question why we can't install XP on power pc processor based computers, see for detail http://forums.techguy.org/apple-macintosh/456495-why-mac-power-pc-processor.html
But Now i am excited because i got a technical reason for my Question, and i want to share it on forum.  
Architectural Differences *
The Power Pc and x86 architectures have some fundamental differences that can prevent code written for one architecture from running properly on the other architecture.
1: Alignment
All PowerPC instructions are 4 bytes in size and must be 4 byte aligned. x86 instruction are variable in size (from 1 to >10 bytes), and as consequence do not need to be aligned.

2: Byte order
Microprocessor architectures commonly use two different byte-ordering methods (little endian and big endian) to store the individual bytes of multibyte data formats in memory. this different become critical important if you try to read data from files that were created on a computer that uses a different byte ordering thatn yours.
for more information about "Byte Order" see this link 
http://developer.apple.com/document...sal_binary_compiling/chapter_2_section_1.html

3: Calling Conventions
The x86 C-language calling convention (application vinary interface, or ABI) specifies that arguments to functions are passed on the stack. The power pc ABI specifies that arguments to funcations are passed in registers. Also, x86 has far fewer registers, So many local veriables use the stack for their storage. Thus, programming errors, or other operation that access past the end of a local variable array or otherwise incorrectly manipulate values on the stack may be more likely to crash applications on x86 systems than on powerpc.

So here i write some difference between Intel and PowerPc, many of other i can't write because i Don't want this a boring topic.
If any one have time and he want to see the Architectural differences then he can visit,
http://developer.apple.com/document...sal_binary_compiling/chapter_2_section_1.html

Thanks for reading this. plz give me your comments, is this a usefull information.
But for me its realy a usefull information.*


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## DoorGah (May 14, 2005)

Hello,
Thanks for taking the time to introduce this type of info. Your audience is probably very limited and I know a lot of users who aren't particularly "moved" by such; but just want their computers to run. And, that's OK.
It may grab the eye of a young person who picks up the ball and makes a career of it though.
Whether you are in the grandstands or on the field of play, participating in this industry is just amazing. Being one of the older members of this forum, I suppose, I'm sure to seem a bit old fashioned in my thoughts. One of these days I'm going to push the button that says Donate... there are expenses.
Going back a few years (!) I remember when the first house in the neighborhood had a TV. All the local kids would go there. Something close to the 5th-6th time, the Mom sent a note home with each of us saying something like "I welcome your children to play with mine and watch TV. Help, I need Kool Aid and sugar..." 
Thanks Again dp


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## [email protected] (Nov 11, 2005)

If you don't have x86 hardware you can not run x86 operating systems. Apple's x86 intels have specially engineered hardware made specifically to run x86. Hard drives are hard drives. Apple uses HFS and Windows uses FAT32 or NTFS. You format a NTFS drive you can't install OS X on it. You format a OS X drive you can not install XP on it. You can partition the drive into two different formats now with boot camp but if you don't have x86 hardware you're left hanging. Get it?


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## abubakar_119 (Apr 5, 2006)

[email protected] said:


> If you don't have x86 hardware you can not run x86 operating systems. Apple's x86 intels have specially engineered hardware made specifically to run x86. Hard drives are hard drives. Apple uses HFS and Windows uses FAT32 or NTFS. You format a NTFS drive you can't install OS X on it. You format a OS X drive you can not install XP on it. You can partition the drive into two different formats now with boot camp but if you don't have x86 hardware you're left hanging. Get it?


Thanks for this kind of information, I know about it and also other differences between x86 and apple computer technology. Acctually the purpose to post this thread is i want to share the difference between x86 and powerpc processors neither differences between other hardware or software.


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