[TUHS] origins of void* -- Apology!

Don Hopkins don at DonHopkins.com
Thu Nov 9 17:14:28 AEST 2017


> On 9 Nov 2017, at 07:37, Lars Brinkhoff <lars at nocrew.org> wrote:
> 
> Bakul Shah wrote:
>> I agree that `char' shouldn't do double duty as the smallest
>> addressable unit and I was suggesing uint8_t does that job.
> 
> There are still machines around where 8-bit bytes isn't a natural fit.

1 bit bytes, the smallest addressable unit on the PDP-10, sounds kinda cool actually. Now would those be signed or unsigned?

The PowerPC was great at smashing and swizzling bit fields and emulating other CPU instruction sets with different memory layouts, because it could rotate and mask very quickly! You could do byte reversal in three instructions: "rotate left" 8 to position two of the bytes, then two “rotate left word immediate then mask insert” instructions. 

https://www.ibm.com/support/knowledgecenter/en/ssw_aix_71/com.ibm.aix.alangref/idalangref_32bit_rtate_shift.htm <https://www.ibm.com/support/knowledgecenter/en/ssw_aix_71/com.ibm.aix.alangref/idalangref_32bit_rtate_shift.htm>

http://sametwice.com/rlwinm <http://sametwice.com/rlwinm>

https://www.google.com/patents/US20140208067 <https://www.google.com/patents/US20140208067>

PowerPC AltiVec was a really beautiful instruction set.

https://en.wikipedia.org/wiki/AltiVec <https://en.wikipedia.org/wiki/AltiVec>

-Don

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