Hello, I met a problem when changing my GCC from v3.4.3 to v4.1.0. Some assembly code which is fine with gcc-3.4.3 cannot work properly any more with gcc-4.1.0. After some investigation, it is because the assembly code uses r12 which is conflict with linker. Below are some excerption from ARM EABI spec (aapcs v2.04), "Both the ARM- and Thumb-state BL instructions are unable to address the full 32-bit address space, so it may be necessary for the linker to insert a veneer between the calling routine and the called subroutine. Veneers may also be needed to support ARM-Thumb inter-working or dynamic linking. Any veneer inserted must preserve the contents of all registers except IP (r12) and the condition code flags; a conforming program must assume that a veneer that alters IP may be inserted at any branch instruction that is exposed to a relocation that supports inter-working or long branches. " I wonder why gcc-4.1.0 has to occupy r12 while gcc-3.4.3 not? -- best regards, -Bridge
