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binary_number/2 is more efficient if you strip off 0's first.

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Simon Forman 2019-04-28 08:16:38 -07:00
parent 67112de952
commit d488db6abd
1 changed files with 5 additions and 5 deletions
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10
thun/compiler.pl
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@ -442,6 +442,8 @@ asm(N, vs_offset(Label)) --> instruction_format_F3b(0, vs, Label, N).
asm(_, vs_link(C)) --> instruction_format_F3a(1, vs, C).
asm(N, vs_link_offset(Label)) --> instruction_format_F3b(1, vs, Label, N).
% This is the core of the assembler where the instruction formats are specified.
instruction_format_F0(U, A, B, Op, C ) --> [0, 0, U, 0], reg(A), reg(B), operation(Op), skip(12), reg(C).
instruction_format_F1(U, V, A, B, Op, Im) --> [0, 1, U, V], reg(A), reg(B), operation(Op), immediate(Im).
instruction_format_F2(U, V, A, B, Offset) --> [1, 0, U, V], reg(A), reg(B), offset(Offset).
@ -455,7 +457,7 @@ skip(N) --> collect(N, Zeros), {Zeros ins 0..0}.
encode_jump_offset(To, Here) --> {Offset is ((To - Here) >> 2) - 1}, encode_int(24, Offset).
encode_int(Width, I) --> {I >= 0}, !, collect(Width, Bits), {binary_number(Bits, I)}, !.
encode_int(Width, I) --> {I >= 0}, !, collect(Width, Bits), { binary_number(Bits, I) }, !.
encode_int(Width, I) --> {I < 0}, !, collect(Width, Bits), {twos_compliment(Bits, I, Width)}, !.
collect(N, []) --> {N =< 0}.
@ -553,10 +555,8 @@ canonical_binary_number([1|Bits], Number):-
canonical_binary_number(Bits1, Number1),
Number is Number1 + 2 ^ Pow.
binary_number(Bits, Number):-
canonical_binary_number(Bits, Number).
binary_number([0|Bits], Number):-
binary_number(Bits, Number).
binary_number([0|Bits], Number) :- binary_number(Bits, Number).
binary_number( Bits , Number) :- canonical_binary_number(Bits, Number).
% Helper code to write the list of bits as a binary file.