On 12/16/2013 11:20 PM, dw wrote: > > On 12/16/2013 3:29 AM, Luchezar Belev wrote: >> Hello, >> Sometimes one needs to pass an immediate operand to asm statement that >> should not be prefixed with dollar sign (e.g. for doing custom things >> with assembly directives). >> >> After much search in the internet i managed to find the way to do it: >> when the operand is used in the assembly string, it must have the 'a' >> modifier. (e.g. ".equ name, %a0" instead of ".equ name, %0". >> >> My question is: why is this feature not mentioned anywhere in the GCC >> documentation and is so extremely hard to find info about? Does this >> mean that it is planned for removal or deprecation? Can one rely on >> it's presence in future GCC versions? >> (I think it is extremely useful for some specific tasks, please don't >> remove it!) >> > I also found the gcc docs for asm to be very limited, so I have been > re-writing them. > > For example, I have documented a number of the modifiers (see > www.LimeGreenSocks.com/gcc/Extended-Asm.html#i386Operandmodifiers). > Because of concerns expressed in some of gcc's bug reports re asm, I > have tried to limit the number of modifiers I doc to those I believe are > essential, and commonly useful. I haven't doc'ed %a. Perhaps %c will > do what you need? > > I haven't had much (actually any) response from the gcc doc people about > this effort. I responded. I reviewed part of it, and there were significant technical inaccuracies that had to be addressed before the changes were considered for inclusion. > But perhaps someday these updates can be rolled back into the docs. Perhaps. What is your copyright assignment status? Andrew.
