From: quadibloc@invalid.invalid   
      
   On Sat, 04 Oct 2025 10:17:41 +0000, Anton Ertl wrote:   
      
   > If the calling convention guarantees that ints are zero-extended (sounds   
   > perverse, but RV64 has the guarantee that unsigned is passed in   
   > sign-extended form, which is equally perverse), then the compiler must   
   > use instructions that produce a zero-extended result (e.g., AMD64's   
   > addl).  If the calling convention only requires and guarantees the   
   > low-order 32 bits (I call this garbage-extended), then the compiler can   
   > use instructions that perform 64-bit adds; this is what we are seeing   
   > above.   
   >   
   > The other side of the medal is what is needed at the caller: If the   
   > caller needs to cconvert a sign-extended int into a long, it does not   
   > have to do anything.   
      
   I find this just a bit confusing.   
      
   Obviously, regular signed integer values should be sign extended.   
      
   But, equally, _unsigned_ integer values should be zero extended for   
   precisely the same reason, so that the longer value, as an unsigned   
   integer, has the same value without doing anything.   
      
   John Savard   
      
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