Re: [PATCH 7/7] RFC: Use correct addresses, eliminate manual relocations

[Pavel Roskin]

Quoting Vladimir 'phcoder' Serbinenko <address@hidden>:

Sorry for the second reply.  I have some new data now.

> AFAIR during compilation process relocation entries are preserved and
> resolved only in the last step. Now thinking it should work even
> without .bss.

I wrongly assumed that I need it to eliminate the ABS macro, which is  
quite intrusive.  It turns out ABS can be eliminated without any .bss  
sections.  I have no idea why ABS appeared originally.  Maybe some  
really old tools couldn't deal with the relocations.

> Anyway don't care much about compiling bootsectors under
> darwin.

We have to care, as we have a lot of preprocessor directives in the  
bootsector sources, and they stand in the way of other changes.  We  
should either maintain that code or discard it.

> Apple's CC generates longer opcodes which breaks bootsectors.

You mean Apple assembler.  And I know why it happens.  The Apple  
assembler assumes unknown labels to be global and generates long  
jumps.  I looked at the source and it looks like only labels starting  
with "L" are considered local.

I prepended "L_" to all labels that are used for jumps, and now the  
Apple assembler creates exactly the same boot.img as the native Linux  
assembler.

> Untill someone finds a fix darwin users will have to use bootsectors
> compiled under linux. It's not a huge problem since very few
> developpers need to modify boot sector

I think I have a fix.  I'll post both patches for boot.S - one to  
remove Apple preprocessor directives and the other to remove ABS.  If  
both work for everyone (I'm worried about Cygwin), we can go ahead  
with other files.

By the way, Apple cpp defines __APPLE__ and __APPLE_CC__, so we don't  
need to define APPLE_CC.  But I hope to get rid of APPLE_CC in most  
places before the rest is converted to __APPLE__.

--
Regards,
Pavel Roskin