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At the lowest level, SubX without syntax sugar uses names without prepositions.
For example, 01 and 03 are both called 'add', irrespective of source and
destination operand. Horizontal space is at a premium, and we rely on the
comments at the end of each line to fully describe what is happening.
Above that, however, we standardize on a slightly different naming convention
across:
a) SubX with syntax sugar,
b) Mu, and
c) the SubX code that the Mu compiler emits.
Conventions, in brief:
- by default, the source is on the left and destination on the right.
e.g. add %eax, 1/r32/ecx ("add eax to ecx")
- prepositions reverse the direction.
e.g. add-to %eax, 1/r32/ecx ("add ecx to eax")
subtract-from %eax, 1/r32/ecx ("subtract ecx from eax")
- by default, comparisons are left to right while 'compare<-' reverses.
Before, I was sometimes swapping args to make the operation more obvious,
but that would complicate the code-generation of the Mu compiler, and it's
nice to be able to read the output of the compiler just like hand-written
code.
One place where SubX differs from Mu: copy opcodes are called '<-' and
'->'. Hopefully that fits with the spirit of Mu rather than the letter
of the 'copy' and 'copy-to' instructions.
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