Discourage assumptions that simply don't hold for all Linux ABIs. Exceptions to the natural alignment rule for scalar types include long long on i386 and sh. --- Documentation/core-api/unaligned-memory-access.rst | 7 ------- 1 file changed, 7 deletions(-) diff --git a/Documentation/core-api/unaligned-memory-access.rst b/Documentation/core-api/unaligned-memory-access.rst index 5ceeb80eb539..1390ce2b7291 100644 --- a/Documentation/core-api/unaligned-memory-access.rst +++ b/Documentation/core-api/unaligned-memory-access.rst @@ -40,9 +40,6 @@ The rule mentioned above forms what we refer to as natural alignment: When accessing N bytes of memory, the base memory address must be evenly divisible by N, i.e. addr % N == 0. -When writing code, assume the target architecture has natural alignment -requirements. - In reality, only a few architectures require natural alignment on all sizes of memory access. However, we must consider ALL supported architectures; writing code that satisfies natural alignment requirements is the easiest way @@ -103,10 +100,6 @@ Therefore, for standard structure types you can always rely on the compiler to pad structures so that accesses to fields are suitably aligned (assuming you do not cast the field to a type of different length). -Similarly, you can also rely on the compiler to align variables and function -parameters to a naturally aligned scheme, based on the size of the type of -the variable. - At this point, it should be clear that accessing a single byte (u8 or char) will never cause an unaligned access, because all memory addresses are evenly divisible by one. -- 2.49.1
