I have a data-conversion function in our ARM9 code which uses varargs. I've been using an arm-elf yagarto distribution from a couple of years ago, with no problems. Recently, we upgraded to the arm-eabi-none yagarto package from the yagarto site, and I'm finding that we now have problems with floating point values. What I eventually discovered is that doubles are being forced to 8-byte boundaries, and the existing varargs floating-point handler didn't expect to find gaps in the args. I can manually check the pointer and force it up to an eight-byte boundary (in fact, I did that, and that fixed the issue entirely), but I'd like to know why this has suddenly started happening. Is there a compiler switch that specifies data alignment on the stack, or in function calls, or something like that?? And why would it be defaulting to 8-byte boundaries on a 32-bit (4-byte) architecture?? I would appreciate any advice or insights that anyone could provide on these issues.