on 3/25/02 4:55 AM, Michael Schmitz at [EMAIL PROTECTED] wrote: >> When compiling the valid code below with -O4, the lines getting the >> va_arg with a float and char will generate this error. Why is this error >> happening under GCC on PPC only? I've seen some posts about this problem > > Because on PPC, doing bad things with va_lists means stack corruption, no > questions asked. > See va-ppc.h for the gory details. > >> /* and here too. */ >> foo_Int8(input, va_arg(args, Int8)); > > Use foo_Int8(input, (int8) va_arg(args, Int32)); > > Michael > >
I understand the corruption with chars (int8) and shorts (int16). However, I will investigate va-ppc.h further, because it seems that in the case when you are passing more than 8 floats, the svr4 abi doesn't promote a 32bit float to a 64bit double and this goes on the arg stack. So I wonder how va-ppc cops with this. You definitely need to pick a 32bit out of the arg stack, so I can't pass a type double when all arguments don't fit in register (and there is 8 byte alignment consideration to make matter worse.) Like I said, I'll dig into this a little bit more tonight. Thanks for the feedback. Cheers, LdS -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
