[swift-dev] Question about size of Character type

Quinn "The Eskimo!" eskimo1 at apple.com
Mon Aug 22 04:03:33 CDT 2016

On 21 Aug 2016, at 02:25, Chris Lattner via swift-dev <swift-dev at swift.org> wrote:

> ARM64 even has a hardware feature for this, called “top byte ignored” (TBI) which means you don’t even have to do the masking.

Urgh, horrible flashbacks to the “32-bit clean” effort during the late 80s:

    Currently the Macintosh OS runs in a 24-bit world, where the hardware ignores 
    the high byte of all memory addresses (including pointers and handles). 
    -- Technote OV11 “The Joy Of Being 32-Bit Clean”



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Quinn "The Eskimo!"                    <http://www.apple.com/developer/>
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

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