From: krishna.myneni@ccreweb.org   
      
   On 3/27/24 08:57, dxf wrote:   
   > On 27/03/2024 10:26 pm, Ruvim wrote:   
   >> On 2024-03-27 04:57, Krishna Myneni wrote:   
   >> [...]   
   >>> We shouldn't have an ambiguous condition here because of some   
   idiosyncratic behavior of the SHL instruction!   
   >>>   
   >>> u 64 LSHIFT should be zero on all systems with cell sizes up to 64 bits.   
   >>   
   >> Ideally — yes.   
   >>   
   >> My rationale (see [1]) is that for any `x` and `u`, the result of a single   
   shift of `x` by `u` bits should always be equivalent to `u` sequential shifts   
   by 1 bit.   
   >>   
   >> But neither the standard nor implementations follow this idea.   
   >   
   > The same occurred with 2/ and 2 / .  Those who saw Forth as a language wanted   
   > consistent results; whereas those who saw Forth as a toolkit said give us   
   what   
   > the hardware provides.   
   >   
      
   If one needs the machine shift instructions, they should be using the   
   Forth assembler to write the word in which it is needed. The language   
   specification has no justification (that I can see) for undefined   
   behavior for the LSHIFT and RSHIFT instructions.   
      
   --   
   Krishna   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)