On Thu, 11 Apr 2024 at 18:22, alines #7777 via Gcc-help <gcc-help@xxxxxxxxxxx> wrote: > > Hello, I was wondering where I could find the source code for the inline assembly feature of the GCC compiler, There isn't just one bit of code for it. Search for RID_ASM for where it's handled by the parser, then you might be able to follow where it goes next. > I’ve been having trouble with an assembly instruction for “bswapl” on a i386 computer with GCC version 2.95. > The bswap instruction works fine with it, however bswapl doesn’t let my code compile, whether I use a long long int for its input as i assume or a 32-bit integer. The compiler says that I’m using invalid operands with the instruction, rather than that the instruction doesn’t exist, and I’m hoping to understand what kind of operands would be valid. Are you sure it's the compiler giving that error, and not the assembler, which is not part of GCC at all?