At 9/3/2020 05:19 PM, Keven wrote:
Couple of things...
[snip]
I wonder, had they instead made XA a 32-bit
system would that mean that z/Architecture would
have to be limited to 63-bits in order to
provide compatibility between (what would have
been) 32-bit 390/ESA and 63-bit z/Architecture
in a manner analogous to how compatibility
between 24-bit S/370 and 31-bit 370/XA systems
was implemented? Â Would (24, 32, 63) have been
a better bit-size expansion sequence than was (24, 31, 64)?
Well, I'm not sure what you're trying to get at
here, Keven, but it does remind me of something
Bob Rogers once said to me... That the z/ARCH
design engineers wanted to implement 63-bit
addressing, but that was vetoed by Marketing...
"There's no way they wanted to have to defend
against Intel's addressing being twice as large as z/ARCH's!"
Dave Cole
ColeSoft Marketing
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Tools: z/XDC for Assembler debugging
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