9 Feb
2010
9 Feb
'10
2 p.m.
On 9 Feb 2010 at 13:14, geoffrey oltmans wrote:
I wonder how much programmers in the 50's and
60's argued about how
many CPU cycles this programming construct took vs. that. ;)
A lot--you also learned to spend your time where it mattered.
As a simple exercise, try writing a CDC 6600 loop to move a non-zero
number of word pairs (non-overlapped), such that you get one
instruction issue per cycle--and two words per loop traversal--and
keep the whole thing in the instruction "stack".
Similarly, a lot of time was spent figuring out bit-twiddling
shortcuts. Some were remarkably clever.
Heck, the code to save and restore all registers was pure cleverness.
It was a different world.
--Chuck