maxmgv documentation 

John Strawn

9/11/87

Suppose that register a contains the maximum of the vector so 
far.  x0 contains the current vector element.  There is a CMPM 
instruction that should at least be considered.  Here is one 
solution:

          move x:(r1),a
          abs  a    x:(r1)+n1,b
		
          do x1,foo2
          cmpm b,a
          jge  foo1
          abs  b
          tfr  b,a
foo1      move      x:(r1)+n1,b
foo2      nop		

This cannot be contracted.  Remember that the Tcc instruction 
does not allow a parallel move.  An inner loop like this takes 7 
instructions without a jump, 5 instructions with a jump.   This 
solution suffers from the jump.

A quicker solution is to ignore the cmpm instruction and to 
calculate the absolute value by hand:
		
          move x:(r1),a
          abs  a    x:(r1)+n1,b

          do x1,foo3
          abs  b
          move      b,x0
          cmp  b,a  x:(r1)+n1,b
foo3      tlt  x0,a      

This solution takes only 4 instructions per pass through the loop.