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X16?

Posted: Thu Jan 28, 2021 7:26 am
by BruceMcF

Ah, the difference between history and marketing. Yes, the 65816 (either name or extended 16 bit operations on the eight bit bus ... and in reality mostly 8bit registers, as 16 bit operations on the A, X, and Y operations typically function a byte per cycle) is the historical origin of the name.

 

"Named in honor of the 16bit address bus over which your Command Extends" is marketing.

 


X16?

Posted: Thu Jan 28, 2021 11:43 am
by TomXP411


4 hours ago, BruceMcF said:




Ah, the difference between history and marketing. Yes, the 65816 (either name or extended 16 bit operations on the eight bit bus ... and in reality mostly 8bit registers, as 16 bit operations on the A, X, and Y operations typically function a byte per cycle) is the historical origin of the name.

 



"Named in honor of the 16bit address bus over which your Command Extends" is marketing.



 



Personally, I'm just happy you can do a 16 bit add with one operation. That alone really makes things easier.

On the other hand, you have to remember what mode the CPU is in: emulation, 8 bit, or 16 bit, or subroutines end up doing things very wrong.

 


X16?

Posted: Fri Jan 29, 2021 5:00 am
by Cyber


21 hours ago, BruceMcF said:




Named in honor of the 16bit address bus . . .



. . . to carry on his spirit? )


X16?

Posted: Fri Jan 29, 2021 1:09 pm
by BruceMcF

Naming in honor is not required to be posthumous.


X16?

Posted: Fri Jan 29, 2021 9:20 pm
by Lorin Millsap
Here's my contribution to the made-up reasons.
The computer is named X16 because it has two separate 8 bit busses. The 65C02 lives on the system bus, and VERA has its own 8 bit bus with 128K of independent video memory. 


Technically the VERA is 32 bit. It fetches 32 bits at a time from VRAM and fills its line buffer. This defines the layer and sprite limitations. But it does present to the system bus as an 8 bit address space.


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