6 Apr
2018
6 Apr
'18
3:56 p.m.
On Wed, Apr 4, 2018 at 7:40 AM, Ivan Gorinov ivan.gorinov@intel.com wrote:
On Wed, Apr 04, 2018 at 12:15:24PM +0800, Bin Meng wrote:
Doesn't readX/writeX imply a single I/O operation? It may be misleading to define it as two.
Assuming MMX or SSE2 to be supported by all x86 processors, 64-bit I/O registers can be accessed as a single operation even in 32-bit code:
Adding such requirement (MMX or SSE2) to U-Boot is not good. Why do we require MMX or SSE2 for readq? Can we use general purpose registers?
In 32-bit code, we can't make a 64-bit memory read operation using only general purpose registers.
Exactly, that's why you have to use non-atomic variants.
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With Best Regards,
Andy Shevchenko