Messages in this thread | | | Date | Fri, 05 Oct 2007 16:10:26 -0500 | From | Timur Tabi <> | Subject | Re: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD |
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Anton Altaparmakov wrote:
>> ---LSB-- ---2SB-- ---3SB-- ---MSB-- [bytes] LITTLE_ENDIAN >> L234567M L234567M L234567M L234567M [bits] LITTLE_ENDIAN_BITFIELD > > No it is not. That makes no sense.
Why not? I honestly don't know what x86 does, but I would think that if I write a 32-bit value to a memory location, that when I examine that memory location, all 32 bits will be in order.
> The whole point of little endian is > that you store LSB, then 2SB, then 3SB, then MSB and then when the CPU
You're talking about byte endian. I'm talking about bit endian -- the order of bits within a byte. Software cannot know what the bit endian is, but external devices that have memory-mapped registers can know.
> reads this as a 32-bit word it rotates them all around so that in the > CPU register you have: > > MSB_3SB_2SB_LSB > M765432L_M765432L_M765432L_M765432L > > That is what little endian means and that is how shift operations can > work fine on the CPU.
The CPU shift operation, yes. I'm talking about shift operations on external memory-mapped devices.
-- Timur Tabi Linux Kernel Developer @ Freescale - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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