On Mon, Jan 29, 2018 at 05:57:47PM +0100, Georg-Johann Lay wrote: > YMMV, I am not even sure if it is correct or even makes complete sense. > > The "m>"(*src) operand doesn't even express that src is changing, and > the constraint allows to use post-increment, but does not force it. src does not change. If the compiler chooses to use a post-increment then this asm will increment the register used. Which is equal to src on input to this asm, but not on output in that case. src is a C variable. The compiler translates C to assembler code that implements the same stuff. Inline assembler integrates with C and the internal GCC representation, not directly with the generated assembler code. Extended asm is not like basic asm (which essentially just drops a block of assembler code in the middle of the compiler's output, no questions asked). > And my experience with inline asm is this: if one doesn't express all > side effects (which is the case for "m>"(src)), then the asm will bite > you sooner or later; even it it appeared to work fine in the past. Certainly. But "m>" describes everything as it should. Segher
