If you are using separate assembly files, gas has a directive to support Intel syntax: .intel_syntax noprefix # not recommended for inline asm which uses Intel syntax and doesn’t need the % prefix before register names. (You can also run as with -msyntax=intel -mnaked-reg to have that as the default instead of att, in case … Read more
The interactions with optimisations are explained about halfway down the “Assembler Instructions with C Expression Operands” page in the documentation. GCC doesn’t try to understand any of the actual assembly inside the asm; the only thing it knows about the content is what you (optionally) tell it in the output and input operand specification and … Read more
Using GCC __asm__(“movl %edx, %eax\n\t” “addl $2, %eax\n\t”); Using VC++ __asm { mov eax, edx add eax, 2 }
See the “Extended Asm” page in the GCC documentation. You can prevent an asm instruction from being deleted by writing the keyword volatile after the asm. […] The volatile keyword indicates that the instruction has important side-effects. GCC will not delete a volatile asm if it is reachable. and An asm instruction without any output … Read more