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David Schultz <david.schultz@earthlink.net> wrote:In the original 68000, a barrel shifter would have blown the areaOn 10/1/24 3:00 PM, Thomas Koenig wrote:>MitchAlsup1 <mitchalsup@aol.com> schrieb:>
>A 32-bit bus would have priced the 68K at 30%-50% higher simply>
due to the number of pins on available packages. This would have
eliminated any chance at competing for the broad markets at that
time.
Would have an external 16-bit bus and an internal 32-bit bus have
been advantageous, or would this have blown a likely transistor
budget for little gain?
Saving an extra pass through the 16 bit ALU for a 32 bit operation would
be faster. Assuming that you didn't have to wait for another bus cycle
to get the other half of an operand.
>
Making it faster for register to register operations and not much else.
A 16 bit barrel roller does not make sense, and Motorola had no idea
that shifts would be so important.
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