vm: change encoding of getv, setv and related.

In most compiler uses of bindv, getv and setv,
the operand which names the dynamic symbol is the data table:
a d0-dff register. The source or destination register of the
transfer could be anything. Therefore, the existing encoding
is suboptimal: the symbol is being put into the full sized
operand field of the instruction, and the source or
destination register into the small, ten-bit extra field
in the upper half. This breaks on cases like (set x y)
where x is a deeply nested lexical variable and y is
a dynamic variable. Let's reverse the encoding.

* share/txr/stdlib/asm.tl (op-getv, op-setv): Reverse the
operands. All derived opcodes follow this since they
reuse the code via inheritance.

* vm.c (vm_get_binding): Fetch the symbol from the small
operand field rather than the main operand field.
(vm_getsym, vm_getbind, vm_setsym, vm_bindv): Pull the
destination or source from the main operand of the instruction
rather than the small opreand.

0 files changed, 0 insertions, 0 deletions