that modify condition codes (the carry bit, in this case). Without
"__volatile", the compiler might add the inline assembler instructions
between unrelated code which also uses condition codes, modifying the
latter.
This prevents the TCP pseudo header checksum calculation done in
tcp_output() from having effects on other conditions when compiled
with GCC 4.2.1 at "-O2" and "options INET6" left out. [1]
Reported & tested by: Boris Kochergin [1]
MFC after: 3 days
operands are consumed so use the appropriate constraint modifier.
Before this change GCC used one register for both an input and an
unrelated output operand of in_addword(), causing the input to be
overwritten before it was consumed and thus breaking in_addword().
For in_cksum_hdr() and in_pseudo() this change is more or less
cosmetic.
- Fix a misspelling in a nearby comment.
Reported & tested by: yongari
MFC after: 1 week
