[ECOS] eCos: ARM in THUMB mode

Gary Stebbins GStebbins@bruxton.com
Fri Dec 7 12:21:00 GMT 2001


I wish to build eCos for ARM / THUMB. I found the patch posted by
Jonathan Larmour on 6-Sep. When I enable Thumb instructions in the eCos
Configuration Tool (V1.3.net 10-Oct-2001), it changes the "Global
command prefix to "thumb-elf". I gather that was for an older version of
gcc. I'm using gcc 3.0.2. Jonathan's same note states that 
 
arm-elf-gcc -mthumb 
 
is correct. However, the Config Tool adds "-mthumb-interwork" to the
Global compiler flags. I haven't found a description of the flags. Do I
need -mthumb-interwork? Do I also need -mthumb?
 
Here are my assumptions. Can someone correct me if I'm wrong?
 
Patch gcc's arm.h as specified by Jonathan.
Change Configuration Tool "Global command prefix" from "thumb-elf" to
"arm-elf"
Add "-mthumb" flag to compiler flags
 
 
Is there anything else I need to know?
 
Thank you.
 
Gary



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