🚀 go-pugleaf

In article <1991Jun13.234834.22970@neon.Stanford.EDU> andy@DEC-Lite.Stanford.EDU (Andy Freeman) writes:
:In article <396@validgh.com> dgh@validgh.com (David G. Hough on validgh) writes:
:>      do 30 i = 2,n
:>         if(abs(dx(i)).le.dmax) go to 30
:>         isamax = i
:>         dmax = abs(dx(i))
:>   30 continue
:
:One instruction that can eliminate the conditional branch is
     ^^^^^^^^^^^^
:conditional assignment.  (It is unclear whether it should be a 3 in 1
:	do 30 i = 2, n
:	    absdx = abs(dx(i))
:	    ibig  = absdx .le. dmax
	    ^^^^^^^^^^^^^^^^^^^^^^^^

I would be very interested in seeing the assembler code that gets
emitted for this line of Fortran. How can this statement get executed
WITHOUT a branch??
 
I also have never seen a machine that has conditional assignment
implemented as an instruction! (As indicated above). What machine is
this? Could you show us the assembler syntax??

I ** believe ** that the above conditional assignment will get compiled
into a test and branch. I don't know of any machine that provides
instructions to do otherwise. It doesn't appear to the Fortan programmer
to be a branch because the branch is 'hidden'.

Of course, I could be wrong.
--
Bob Silverman
#include <std.disclaimer>
Mitre Corporation, Bedford, MA 01730
"You can lead a horse's ass to knowledge, but you can't make him think"