WLAN from SDIO to SPI: battle plan
andy at openmoko.com
Thu Aug 28 20:40:55 CEST 2008
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Somebody in the thread at some point said:
| Am Do 28. August 2008 schrieb Andy Green:
|> Somebody in the thread at some point said:
|> | Am Do 28. August 2008 schrieb Andy Green:
|> |> The problem comes when the guys you need aligned are inside a struct
|> |> that does correctly position them at alignment boundary -- relative to
|> |> struct start. If the address of the start of the struct is not itself
|> |> aligned to the machine word size though, that doesn't help at all.
|> |> So a u32 at +8 from the struct start looks like it follows the rules
|> |> great, but if the struct pointer is pointing to 0x1, you are screwed
|> |> when you try to dereference that u32 in one 32-bit access at 0x9.
|> |> __packed__ is magic get out of jail card for that case.
|> | I'd prefer memmove'ing such missaligned structs to an auxiliary buffer
|> | aligned the way it needs to be. Maybe even with a half word padding on
|> | and tail.
|> Why are we interested in your "preferences" about this?
| We are very interested in your answer to your own question, as you are
| only one who can answer it, at least when it comes up to you.
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