diff --git a/src/inline-assembly.md b/src/inline-assembly.md index 26f1acedc..34a81e7f3 100644 --- a/src/inline-assembly.md +++ b/src/inline-assembly.md @@ -416,8 +416,10 @@ Currently the following options are defined: This allows the compiler to execute the `asm!` block fewer times than specified in the program (e.g. by hoisting it out of a loop) or even eliminate it entirely if the outputs are not used. - `nomem`: The `asm!` blocks does not read or write to any memory. This allows the compiler to cache the values of modified global variables in registers across the `asm!` block since it knows that they are not read or written to by the `asm!`. + The compiler also assumes that this `asm!` block does not perform any kind of synchronization with other threads, e.g. via fences. - `readonly`: The `asm!` block does not write to any memory. This allows the compiler to cache the values of unmodified global variables in registers across the `asm!` block since it knows that they are not written to by the `asm!`. + The compiler also assumes that this `asm!` block does not perform any kind of synchronization with other threads, e.g. via fences. - `preserves_flags`: The `asm!` block does not modify the flags register (defined in the rules below). This allows the compiler to avoid recomputing the condition flags after the `asm!` block. - `noreturn`: The `asm!` block never returns, and its return type is defined as `!` (never).