Konrad Schwarz (no.spam@no.spam) on 7/7/10 wrote:
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> Well, all my RISC machines work exactly this way, and I'm sure the x86 people > would rather not have to deal with AH, AL, AX, EAX and RAX etc.

Dunno if you think that Power still qualifies for RISC, but at least there, though they use a common register format for floating point, there is a whole set of parallel ISA for double and single precision ops that round differently in the 64-bit register. See also AltiVec and SPE with specific ISA for each.

Likewise, on the integer side, due to the arithmetic miracles of 2's complement, special instructions for smaller integer types aren't required for addition, subtraction and low-half multiplication. Just ignore the upper bits. In cases where they matter, a cheap AND or sign extend are all that are required to make full multiplication and division work.

So, I'm not really sure that your assertion is true, in that what would be required to provide full support for native arithmetic in every data type is probably relatively minor.