GCC 3.2.1 arm assembler error

Ryan Pipkin ryan.pipkin@inet.com
Wed Apr 16 17:59:00 GMT 2003


Can someone please verify that this is a problem.  Referring to the 
APCS  a0 - a3, and ip  are used between procedure calls.  Therefore the 
local routine cannot assume any values for these registers beyond a 
branch and link.  When used again they must be loaded again.  I have 
included two samples from a dissassembled object file in which it looks 
like they are being used incorrectly.  I have tested on 3 compiler 
versions as indicated.


Here are the compiler options used:
-c -nostdinc -O3 -mcpu=xscale -msoft-float -mapcs-32 -fno-rtti 
-fno-exceptions -fsigned-char -fno-builtin -b arm-unknown-elf -V 3.2.1

Using 2.96 is not an option due to a stack corruption problem.  I only 
included it in these results for comparision.


3.2.1    (rebuilt from source --target=arm-unknown-elf)
 d8:    e50bc02c     str    ip, [fp, -#44]
 dc:    ebfffffe     bl    0 <_ZN12PciXScaleDevC2Ej>
 e0:    e289e09c     add    lr, r9, #156    ; 0x9c
 e4:    e58ce21c     str    lr, [ip, #540]


3.1        (GNUPRO xscale-020523)
     d8:    e50b302c     str    r3, [fp, -#44]
     dc:    ebfffffe     bl    0 <_ZN12PciXScaleDevC2Ej>
     e0:    e289a09c     add    sl, r9, #156    ; 0x9c
     e4:    e583a21c     str    sl, [r3, #540]

Same problem different register.


2.96    (GNUPRO xscale-010827)
    I could not find any instance of r0,r1,r2,r3,ip being used with 
assumed value after a bl call.


   Ryan.




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