RE: [PATCH v2] x86: modernize sync_bitops.h

[David Laight]

From: Jan Beulich
> Sent: 21 November 2018 10:11
> 
> Add missing insn suffixes and use rmwcc.h just like was (more or less)
> recently done for bitops.h as well.

Why? bts (etc) on memory don't really have an 'operand size'.
IIRC the suffix determines the width of the %cx register that selects the bit number.
I'd have to look up what the "Ir" constraint means.

IIRC the i386 book just said that the cpu might (aka will) read/write 4 bytes
surrounding the required byte.
More recent books say it does an aligned 4 byte read/write.

	David

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