WLAN from SDIO to SPI: battle plan
andy at openmoko.com
Thu Aug 28 20:28:00 CEST 2008
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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?
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