%---------------------------------------------------------------------------% % vim: ts=4 sw=4 et ft=mercury %---------------------------------------------------------------------------% % Copyright (C) 2017-2022 The Mercury team. % This file is distributed under the terms specified in COPYING.LIB. %---------------------------------------------------------------------------% % % File: uint16.m % Main author: juliensf % Stability: low. % % Predicates and functions for dealing with unsigned 16-bit integer numbers. % %---------------------------------------------------------------------------% :- module uint16. :- interface. :- import_module pretty_printer. %---------------------------------------------------------------------------% % % Conversion from int. % % from_int(I, U16): % % Convert an int into a uint16. % Fails if I is not in [0, 2^16 - 1]. % :- pred from_int(int::in, uint16::out) is semidet. % det_from_int(I) = U16: % % Convert an int into a uint16. % Throws an exception if I is not in [0, 2^16 - 1]. % :- func det_from_int(int) = uint16. % cast_from_int(I) = U16: % % Convert an int to a uint16. % Always succeeds, but will yield a result that is mathematically equal % to I only if I is in [0, 2^16 - 1]. % :- func cast_from_int(int) = uint16. %---------------------------------------------------------------------------% % % Conversion from uint. % % from_uint(U, U16): % % Convert a uint into a uint16. % Fails if U is not in [0, 2^16 - 1]. % :- pred from_uint(uint::in, uint16::out) is semidet. % det_from_uint(U) = U16: % % Convert a uint into a uint16. % Throws an exception if U is not in [0, 2^16 - 1]. % :- func det_from_uint(uint) = uint16. % cast_from_uint(U) = U16: % % Convert a uint to a uint16. % Always succeeds, but will yield a result that is mathematically equal % to U only if U is in [0, 2^16 - 1]. % :- func cast_from_uint(uint) = uint16. %---------------------------------------------------------------------------% % % Conversion to int. % % to_int(U16) = I: % % Convert a uint16 to an int. % Always succeeds, and yields a result that is mathematically equal % to U16. % :- func to_int(uint16) = int. % cast_to_int(U16) = I: % % Convert a uint16 to an int. % Always succeeds, and yields a result that is mathematically equal % to U16. % :- func cast_to_int(uint16) = int. %---------------------------------------------------------------------------% % % Conversion to uint. % % cast_to_uint(U16) = U: % % Convert a uint16 to a uint. % Always succeeds, and yields a result that is mathematically equal % to U16. % :- func cast_to_uint(uint16) = uint. %---------------------------------------------------------------------------% % % Conversion to/from uint8 % % cast_to_uint8(U16) = U8: % % Convert a uint16 to a uint8. % Always succeeds, but will yield a result that is mathematically equal % to U16 only if U16 is in [0, 2^8 - 1]. % :- func cast_to_uint8(uint16) = uint8. % cast_from_uint8(U8) = U16: % % Convert a uint8 to a uint16. % Always succeeds, and yields a result that is mathematically equal % to U8. % :- func cast_from_uint8(uint8) = uint16. %---------------------------------------------------------------------------% % % Conversion to/from uint64. % % cast_to_uint64(U16) = U64: % % Convert a uint16 to a uint64. % Always succeeds, and yields a result that is mathematically equal % to U16. % :- func cast_to_uint64(uint16) = uint64. % cast_from_uint64(U64) = U16: % % Convert a uint64 to a uint16. % Always succeeds, but will yield a result that is mathematically equal % to U64 only if U64 is in [0, 2^16 - 1]. % :- func cast_from_uint64(uint64) = uint16. %---------------------------------------------------------------------------% % % Change of signedness. % % cast_from_int16(I16) = U16: % % Convert an int16 to a uint16. This will yield a result that is % mathematically equal to I16 only if I16 is in [0, 2^15 - 1]. % :- func cast_from_int16(int16) = uint16. %---------------------------------------------------------------------------% % % Conversion from byte sequence. % % from_bytes_le(LSB, MSB) = U16: % % U16 is the uint16 whose least and most significant bytes are given by the % uint8s LSB and MSB respectively. % :- func from_bytes_le(uint8, uint8) = uint16. % from_bytes_be(MSB, LSB) = U16: % % U16 is the uint16 whose least and most significant bytes are given by the % uint8s LSB and MSB respectively. % :- func from_bytes_be(uint8, uint8) = uint16. %---------------------------------------------------------------------------% % % Comparisons and related operations. % % Less than. % :- pred (uint16::in) < (uint16::in) is semidet. % Greater than. % :- pred (uint16::in) > (uint16::in) is semidet. % Less than or equal. % :- pred (uint16::in) =< (uint16::in) is semidet. % Greater than or equal. % :- pred (uint16::in) >= (uint16::in) is semidet. % Maximum. % :- func max(uint16, uint16) = uint16. % Minimum. % :- func min(uint16, uint16) = uint16. %---------------------------------------------------------------------------% % % Arithmetic operations. % % Addition. % :- func uint16 + uint16 = uint16. :- mode in + in = uo is det. :- mode uo + in = in is det. :- mode in + uo = in is det. :- func plus(uint16, uint16) = uint16. % Subtraction. % :- func uint16 - uint16 = uint16. :- mode in - in = uo is det. :- mode uo - in = in is det. :- mode in - uo = in is det. :- func minus(uint16, uint16) = uint16. % Multiplication. % :- func (uint16::in) * (uint16::in) = (uint16::uo) is det. :- func times(uint16, uint16) = uint16. % Truncating integer division. % % Throws a `domain_error' exception if the right operand is zero. % :- func (uint16::in) div (uint16::in) = (uint16::uo) is det. % Truncating integer division. % % Throws a `domain_error' exception if the right operand is zero. % :- func (uint16::in) // (uint16::in) = (uint16::uo) is det. % (/)/2 is a synonym for (//)/2. % :- func (uint16::in) / (uint16::in) = (uint16::uo) is det. % unchecked_quotient(X, Y) is the same as X // Y, but the behaviour % is undefined if the right operand is zero. % :- func unchecked_quotient(uint16::in, uint16::in) = (uint16::uo) is det. % Modulus. % X mod Y = X - (X div Y) * Y % % Throws a `domain_error' exception if the right operand is zero. % :- func (uint16::in) mod (uint16::in) = (uint16::uo) is det. % Remainder. % X rem Y = X - (X // Y) * Y. % % Throws a `domain_error/` exception if the right operand is zero. % :- func (uint16::in) rem (uint16::in) = (uint16::uo) is det. % unchecked_rem(X, Y) is the same as X rem Y, but the behaviour is % undefined if the right operand is zero. % :- func unchecked_rem(uint16::in, uint16::in) = (uint16::uo) is det. % even(X) is equivalent to (X mod 2 = 0). % :- pred even(uint16::in) is semidet. % odd(X) is equivalent to (not even(X)), i.e. (X mod 2 = 1). % :- pred odd(uint16::in) is semidet. %---------------------------------------------------------------------------% % % Shift operations. % % Left shift. % X << Y returns X "left shifted" by Y bits. % The bit positions vacated by the shift are filled by zeros. % Throws an exception if Y is not in [0, 16). % :- func (uint16::in) << (int::in) = (uint16::uo) is det. :- func (uint16::in) <> Y returns X "right shifted" by Y bits. % The bit positions vacated by the shift are filled by zeros. % Throws an exception if Y is not in [0, 16). % :- func (uint16::in) >> (int::in) = (uint16::uo) is det. :- func (uint16::in) >>u (uint::in) = (uint16::uo) is det. % unchecked_right_shift(X, Y) is the same as X >> Y except that the % behaviour is undefined if Y is not in [0, 16). % It will typically be implemented more efficiently than X >> Y. % :- func unchecked_right_shift(uint16::in, int::in) = (uint16::uo) is det. :- func unchecked_right_ushift(uint16::in, uint::in) = (uint16::uo) is det. %---------------------------------------------------------------------------% % % Logical operations. % % Bitwise and. % :- func (uint16::in) /\ (uint16::in) = (uint16::uo) is det. % Bitwise or. % :- func (uint16::in) \/ (uint16::in) = (uint16::uo) is det. % Bitwise exclusive or (xor). % :- func xor(uint16, uint16) = uint16. :- mode xor(in, in) = uo is det. :- mode xor(in, uo) = in is det. :- mode xor(uo, in) = in is det. % Bitwise complement. % :- func \ (uint16::in) = (uint16::uo) is det. %---------------------------------------------------------------------------% % % Operations on bits and bytes. % % num_zeros(U) = N: % % N is the number of zeros in the binary representation of U. % :- func num_zeros(uint16) = int. % num_ones(U) = N: % % N is the number of ones in the binary representation of U. % :- func num_ones(uint16) = int. % num_leading_zeros(U) = N: % % N is the number of leading zeros in the binary representation of U, % starting at the most significant bit position. % Note that num_leading_zeros(0u16) = 16. % :- func num_leading_zeros(uint16) = int. % num_trailing_zeros(U) = N: % % N is the number of trailing zeros in the binary representation of U, % starting at the least significant bit position. % Note that num_trailing_zeros(0u16) = 16. % :- func num_trailing_zeros(uint16) = int. % reverse_bytes(A) = B: % % B is the value that results from reversing the bytes in the binary % representation of A. % :- func reverse_bytes(uint16) = uint16. % reverse_bits(A) = B: % % B is the is value that results from reversing the bits in the binary % representation of A. % :- func reverse_bits(uint16) = uint16. % rotate_left(U, D) = N: % % N is the value obtained by rotating the binary representation of U % left by D bits. Throws an exception if D is not in the range [0, 15]. % :- func rotate_left(uint16, uint) = uint16. % unchecked_rotate_left(U, D) = N: % % N is the value obtained by rotating the binary representation of U % left by an amount given by the lowest 4 bits of D. % :- func unchecked_rotate_left(uint16, uint) = uint16. % rotate_right(U, D) = N: % % N is the value obtained by rotating the binary representation of U % right by D bits. Throws an exception if D is not in the range [0, 15]. % :- func rotate_right(uint16, uint) = uint16. % unchecked_rotate_left(U, D) = N: % % N is the value obtained by rotating the binary representation of U % right by an amount given by the lowest 4 bits of D. % :- func unchecked_rotate_right(uint16, uint) = uint16. % set_bit(U, I) = N: % N is the value obtained by setting the I'th bit (the bit worth 2^I) of U % to one. An exception is thrown if I is not in the range [0, 15]. % :- func set_bit(uint16, uint) = uint16. % unchecked_set_bit(U, I) = N: % As above, but the behaviour is undefined if I is not in the range % [0, 15]. % :- func unchecked_set_bit(uint16, uint) = uint16. % clear_bit(U, I) = N: % N is the value obtained by setting the I'th bit (the bit worth 2^I) of U % to zero. An exception is thrown if I is not in the range [0, 15]. % :- func clear_bit(uint16, uint) = uint16. % unchecked_clear_bit(U, I) = N: % As above, but the behaviour is undefined if I is not in the range % [0, 15]. % :- func unchecked_clear_bit(uint16, uint) = uint16. % flip_bit(U, I) = N: % N is the value obtained by flipping the I'th bit (the bit worth 2^I) of % U. An exception is thrown if I is not in the range [0, 15]. % :- func flip_bit(uint16, uint) = uint16. % unchecked_flip_bit(U, I) = N: % As above, but the behaviour is undefined if I is not in the range % [0, 15]. % :- func unchecked_flip_bit(uint16, uint) = uint16. % bit_is_set(U, I): % True iff the I'th bit (the bit worth 2^I) of U is one. % An exception is thrown if I is not in the range [0, 15]. % :- pred bit_is_set(uint16::in, uint::in) is semidet. % unchecked_bit_is_set(U, I): % As above, but the behaviour is undefined if I is not in the range % [0, 15]. % :- pred unchecked_bit_is_set(uint16::in, uint::in) is semidet. % bit_is_clear(U, I): % True iff the I'th bit (the bit worth 2^I) of U is zero. % An exception is thrown if I is not in the range [0, 15]. % :- pred bit_is_clear(uint16::in, uint::in) is semidet. % unchecked_bit_is_clear(U, I): % As above, but the behaviour is undefined if I is not in the range % [0, 15]. % :- pred unchecked_bit_is_clear(uint16::in, uint::in) is semidet. %---------------------------------------------------------------------------% % % Limits. % :- func max_uint16 = uint16. %---------------------------------------------------------------------------% % % Prettyprinting. % % Convert a uint16 to a pretty_printer.doc for formatting. % :- func uint16_to_doc(uint16) = pretty_printer.doc. :- pragma obsolete(func(uint16_to_doc/1), [pretty_printer.uint16_to_doc/1]). %---------------------------------------------------------------------------% %---------------------------------------------------------------------------% :- implementation. :- import_module exception. :- import_module int. :- import_module require. :- import_module uint. %---------------------------------------------------------------------------% from_int(I, U8) :- I >= 0, I =< 65_535, U8 = cast_from_int(I). det_from_int(I) = U16 :- ( if from_int(I, U16Prime) then U16 = U16Prime else error($pred, "cannot convert int to uint16") ). :- pragma foreign_proc("C", cast_from_int(I::in) = (U16::out), [will_not_call_mercury, promise_pure, thread_safe, will_not_modify_trail, does_not_affect_liveness], " U16 = (uint16_t) I; "). :- pragma foreign_proc("C#", cast_from_int(I::in) = (U16::out), [will_not_call_mercury, promise_pure, thread_safe], " U16 = (ushort) I; "). :- pragma foreign_proc("Java", cast_from_int(I::in) = (U16::out), [will_not_call_mercury, promise_pure, thread_safe], " U16 = (short) I; "). %---------------------------------------------------------------------------% from_uint(U, U16) :- U =< 65_535u, U16 = cast_from_uint(U). det_from_uint(U) = U16 :- ( if from_uint(U, U16Prime) then U16 = U16Prime else error($pred, "cannot convert uint to uint16") ). :- pragma foreign_proc("C", cast_from_uint(U::in) = (U16::out), [will_not_call_mercury, promise_pure, thread_safe, will_not_modify_trail, does_not_affect_liveness], " U16 = (uint16_t) U; "). :- pragma foreign_proc("C#", cast_from_uint(U::in) = (U16::out), [will_not_call_mercury, promise_pure, thread_safe], " U16 = (ushort) U; "). :- pragma foreign_proc("Java", cast_from_uint(U::in) = (U16::out), [will_not_call_mercury, promise_pure, thread_safe], " U16 = (short) U; "). %---------------------------------------------------------------------------% :- pragma foreign_proc("C", to_int(U16::in) = (I::out), [will_not_call_mercury, promise_pure, thread_safe, will_not_modify_trail, does_not_affect_liveness], " I = U16; "). :- pragma foreign_proc("C#", to_int(U16::in) = (I::out), [will_not_call_mercury, promise_pure, thread_safe], " I = U16; "). :- pragma foreign_proc("Java", to_int(U16::in) = (I::out), [will_not_call_mercury, promise_pure, thread_safe], " I = U16 & 0xffff; "). :- pragma foreign_proc("C", cast_to_int(U16::in) = (I::out), [will_not_call_mercury, promise_pure, thread_safe, will_not_modify_trail, does_not_affect_liveness], " I = U16; "). :- pragma foreign_proc("C#", cast_to_int(U16::in) = (I::out), [will_not_call_mercury, promise_pure, thread_safe], " I = U16; "). :- pragma foreign_proc("Java", cast_to_int(U16::in) = (I::out), [will_not_call_mercury, promise_pure, thread_safe], " I = U16 & 0xffff; "). %---------------------------------------------------------------------------% :- pragma foreign_proc("C", cast_to_uint(U16::in) = (U::out), [will_not_call_mercury, promise_pure, thread_safe, will_not_modify_trail, does_not_affect_liveness], " U = (MR_Unsigned) U16; "). :- pragma foreign_proc("C#", cast_to_uint(U16::in) = (U::out), [will_not_call_mercury, promise_pure, thread_safe], " U = (uint) U16; "). :- pragma foreign_proc("Java", cast_to_uint(U16::in) = (U::out), [will_not_call_mercury, promise_pure, thread_safe], " U = U16 & 0xffff; "). %---------------------------------------------------------------------------% :- pragma foreign_proc("C", cast_to_uint8(U16::in) = (U8::out), [will_not_call_mercury, promise_pure, thread_safe, will_not_modify_trail, does_not_affect_liveness], " U8 = (uint8_t) U16; "). :- pragma foreign_proc("C#", cast_to_uint8(U16::in) = (U8::out), [will_not_call_mercury, promise_pure, thread_safe], " U8 = (byte) U16; "). :- pragma foreign_proc("Java", cast_to_uint8(U16::in) = (U8::out), [will_not_call_mercury, promise_pure, thread_safe], " U8 = (byte) U16; "). %---------------------------------------------------------------------------% :- pragma foreign_proc("C", cast_from_uint8(U8::in) = (U16::out), [will_not_call_mercury, promise_pure, thread_safe, will_not_modify_trail, does_not_affect_liveness], " U16 = (uint16_t) U8; "). :- pragma foreign_proc("C#", cast_from_uint8(U8::in) = (U16::out), [will_not_call_mercury, promise_pure, thread_safe], " U16 = (ushort) U8; "). :- pragma foreign_proc("Java", cast_from_uint8(U8::in) = (U16::out), [will_not_call_mercury, promise_pure, thread_safe], " U16 = (short) (U8 & 0xff); "). %---------------------------------------------------------------------------% :- pragma foreign_proc("C", cast_to_uint64(U16::in) = (U64::out), [will_not_call_mercury, promise_pure, thread_safe, will_not_modify_trail, does_not_affect_liveness], " U64 = (uint64_t) U16; "). :- pragma foreign_proc("C#", cast_to_uint64(U16::in) = (U64::out), [will_not_call_mercury, promise_pure, thread_safe], " U64 = (ulong) U16; "). :- pragma foreign_proc("Java", cast_to_uint64(U16::in) = (U64::out), [will_not_call_mercury, promise_pure, thread_safe], " U64 = (long) U16 & 0xffffL; "). %---------------------------------------------------------------------------% :- pragma foreign_proc("C", cast_from_uint64(U64::in) = (U16::out), [will_not_call_mercury, promise_pure, thread_safe, will_not_modify_trail, does_not_affect_liveness], " U16 = (uint16_t) U64; "). :- pragma foreign_proc("C#", cast_from_uint64(U64::in) = (U16::out), [will_not_call_mercury, promise_pure, thread_safe], " U16 = (ushort) U64; "). :- pragma foreign_proc("Java", cast_from_uint64(U64::in) = (U16::out), [will_not_call_mercury, promise_pure, thread_safe], " U16 = (short) U64; "). %---------------------------------------------------------------------------% :- pragma foreign_proc("C", cast_from_int16(I16::in) = (U16::out), [will_not_call_mercury, promise_pure, thread_safe, will_not_modify_trail, does_not_affect_liveness], " U16 = (uint16_t) I16; "). :- pragma foreign_proc("C#", cast_from_int16(I16::in) = (U16::out), [will_not_call_mercury, promise_pure, thread_safe], " U16 = (ushort) I16; "). :- pragma foreign_proc("Java", cast_from_int16(I16::in) = (U16::out), [will_not_call_mercury, promise_pure, thread_safe], " U16 = I16; "). %---------------------------------------------------------------------------% :- pragma foreign_proc("C", from_bytes_le(LSB::in, MSB::in) = (U16::out), [will_not_call_mercury, promise_pure, thread_safe, will_not_modify_trail], " unsigned char *uint16_bytes = (unsigned char *) &U16; #if defined(MR_BIG_ENDIAN) uint16_bytes[0] = MSB; uint16_bytes[1] = LSB; #else uint16_bytes[0] = LSB; uint16_bytes[1] = MSB; #endif "). :- pragma foreign_proc("Java", from_bytes_le(LSB::in, MSB::in) = (U16::out), [will_not_call_mercury, promise_pure, thread_safe], " U16 = (short) (MSB << java.lang.Byte.SIZE | (LSB & 0x00ff)); "). :- pragma foreign_proc("C#", from_bytes_le(LSB::in, MSB::in) = (U16::out), [will_not_call_mercury, promise_pure, thread_safe], " U16 = (ushort) (MSB << 8 | (LSB & 0x00ff)); "). from_bytes_be(MSB, LSB) = from_bytes_le(LSB, MSB). %---------------------------------------------------------------------------% % The comparison operations <, >, =< and >= are builtins. max(X, Y) = ( if X > Y then X else Y ). min(X, Y) = ( if X < Y then X else Y ). %---------------------------------------------------------------------------% % The operations +, -, plus, minus, *, and times are builtins. X div Y = X // Y. :- pragma inline(func('//'/2)). X // Y = Div :- ( if Y = 0u16 then throw(domain_error("uint16.'//': division by zero")) else Div = unchecked_quotient(X, Y) ). :- pragma inline(func('/'/2)). X / Y = X // Y. X mod Y = X rem Y. :- pragma inline(func(rem/2)). X rem Y = Rem :- ( if Y = 0u16 then throw(domain_error("uint16.rem: division by zero")) else Rem = unchecked_rem(X, Y) ). :- pragma inline(pred(even/1)). even(X) :- (X /\ 1u16) = 0u16. :- pragma inline(pred(odd/1)). odd(X) :- (X /\ 1u16) \= 0u16. %---------------------------------------------------------------------------% % The unchecked shift operations are builtins. X << Y = Result :- ( if cast_from_int(Y) < 16u then Result = unchecked_left_shift(X, Y) else Msg = "uint16.(<<): second operand is out of range", throw(domain_error(Msg)) ). X <> Y = Result :- ( if cast_from_int(Y) < 16u then Result = unchecked_right_shift(X, Y) else Msg = "uint16.(>>): second operand is out of range", throw(domain_error(Msg)) ). X >>u Y = Result :- ( if Y < 16u then Result = unchecked_right_ushift(X, Y) else Msg = "uint16.(>>u): second operand is out of range", throw(domain_error(Msg)) ). %---------------------------------------------------------------------------% % The algorithms in this section are adapted from chapter 5 of % ``Hacker's Delight'' by Henry S. Warren, Jr. num_zeros(U) = 16 - num_ones(U). :- pragma foreign_proc("C", num_ones(U::in) = (N::out), [will_not_call_mercury, promise_pure, thread_safe, will_not_modify_trail], " U = (U & 0x5555) + ((U >> 1) & 0x5555); U = (U & 0x3333) + ((U >> 2) & 0x3333); U = (U & 0x0f0f) + ((U >> 4) & 0x0f0f); U = (U & 0x00ff) + ((U >> 8) & 0x00ff); N = U; "). :- pragma foreign_proc("C#", num_ones(U::in) = (N::out), [will_not_call_mercury, promise_pure, thread_safe], " U = (ushort) ((U & 0x5555) + ((U >> 1) & 0x5555)); U = (ushort) ((U & 0x3333) + ((U >> 2) & 0x3333)); U = (ushort) ((U & 0x0f0f) + ((U >> 4) & 0x0f0f)); U = (ushort) ((U & 0x00ff) + ((U >> 8) & 0x00ff)); N = (int) U; "). :- pragma foreign_proc("Java", num_ones(U::in) = (N::out), [will_not_call_mercury, promise_pure, thread_safe], " N = java.lang.Integer.bitCount(U << 16); "). %---------------------% :- pragma foreign_proc("C", num_leading_zeros(U::in) = (N::out), [will_not_call_mercury, promise_pure, thread_safe, will_not_modify_trail], " if (U == 0) { N = 16; } else { int n = 1; if ((U >> 8) == 0) { n = n + 8; U = U << 8; } if ((U >> 12) == 0) { n = n + 4; U = U << 4; } if ((U >> 14) == 0) { n = n + 2; U = U << 2; } if ((U >> 15) == 0) { n = n + 1; U = U << 1; } N = n - (int) (U >> 15); } "). :- pragma foreign_proc("C#", num_leading_zeros(U::in) = (N::out), [will_not_call_mercury, promise_pure, thread_safe], " if (U == 0) { N = 16; } else { int n = 1; if ((U >> 8) == 0) { n = n + 8; U = (ushort) (U << 8); } if ((U >> 12) == 0) { n = n + 4; U = (ushort) (U << 4); } if ((U >> 14) == 0) { n = n + 2; U = (ushort) (U << 2); } if ((U >> 15) == 0) { n = n + 1; U = (ushort) (U << 1); } N = n - (int) (U >> 15); } "). :- pragma foreign_proc("Java", num_leading_zeros(I::in) = (N::out), [will_not_call_mercury, promise_pure, thread_safe], " if (I == 0) { N = 16; } else { N = java.lang.Integer.numberOfLeadingZeros(I << 16); } "). %---------------------% num_trailing_zeros(U) = 16 - num_leading_zeros(\ U /\ (U - 1u16)). %---------------------% :- pragma foreign_proc("C", reverse_bytes(A::in) = (B::out), [will_not_call_mercury, promise_pure, thread_safe, will_not_modify_trail], " B = MR_uint16_reverse_bytes(A); "). :- pragma foreign_proc("Java", reverse_bytes(A::in) = (B::out), [will_not_call_mercury, promise_pure, thread_safe], " B = java.lang.Short.reverseBytes(A); "). reverse_bytes(A) = B :- B = (A >> 8) \/ (A << 8). %---------------------% :- pragma foreign_proc("Java", reverse_bits(A::in) = (B::out), [will_not_call_mercury, promise_pure, thread_safe], " B = (short) (java.lang.Integer.reverse(A << 16) & 0xffff); "). reverse_bits(!.A) = B :- !:A = (((\ 0x5555u16) /\ !.A) >> 1) \/ ((0x5555u16 /\ !.A) << 1), !:A = (((\ 0x3333u16) /\ !.A) >> 2) \/ ((0x3333u16 /\ !.A) << 2), !:A = (((\ 0x0f0fu16) /\ !.A) >> 4) \/ ((0x0f0fu16 /\ !.A) << 4), !:A = (((\ 0x00ffu16) /\ !.A) >> 8) \/ ((0x00ffu16 /\ !.A) << 8), B = !.A. %---------------------------------------------------------------------------% rotate_left(X, N) = ( if N < 16u then unchecked_rotate_left(X, N) else func_error($pred, "rotate amount exceeds 15 bits") ). :- pragma foreign_proc("C", unchecked_rotate_left(X::in, N::in) = (Result::out), [will_not_call_mercury, promise_pure, thread_safe], " N &= 15; // XXX clang has intrinsics for rotation -- we should use those instead. Result = (X << N) | (X >> (-N & 15)); "). :- pragma foreign_proc("C#", unchecked_rotate_left(X::in, N::in) = (Result::out), [will_not_call_mercury, promise_pure, thread_safe], " N &= 15; Result = (ushort) ((X << (int) N) | (X >> (int) (-N & 15))); "). :- pragma foreign_proc("Java", unchecked_rotate_left(X::in, N::in) = (Result::out), [will_not_call_mercury, promise_pure, thread_safe], " N &= 15; Result = (short) ((X << (int) N) | (X >>> (int) (-N & 15))); "). %---------------------------------------------------------------------------% rotate_right(X, N) = ( if N < 16u then unchecked_rotate_right(X, N) else func_error($pred, "rotate amount exceeds 15 bits") ). :- pragma foreign_proc("C", unchecked_rotate_right(X::in, N::in) = (Result::out), [will_not_call_mercury, promise_pure, thread_safe], " N &= 15; Result = (X >> N) | (X << (-N & 15)); "). :- pragma foreign_proc("C#", unchecked_rotate_right(X::in, N::in) = (Result::out), [will_not_call_mercury, promise_pure, thread_safe], " N &= 15; Result = (ushort) ((X >> (int) N) | (X << (int) (-N & 15))); "). :- pragma foreign_proc("Java", unchecked_rotate_right(X::in, N::in) = (Result::out), [will_not_call_mercury, promise_pure, thread_safe], " N &= 15; Result = (short) ((X >>> (int) N) | (X << (int) (-N & 15))); "). %---------------------------------------------------------------------------% set_bit(U, I) = ( if I < 16u then unchecked_set_bit(U, I) else func_error($pred, "bit index exceeds 15 bits") ). unchecked_set_bit(U, I) = U \/ (1u16 `unchecked_left_shift` cast_to_int(I)). clear_bit(U, I) = ( if I < 16u then unchecked_clear_bit(U, I) else func_error($pred, "bit index exceeds 15 bits") ). unchecked_clear_bit(U, I) = U /\ (\ (1u16 `unchecked_left_shift` cast_to_int(I))). flip_bit(U, I) = ( if I < 16u then unchecked_flip_bit(U, I) else func_error($pred, "bit index exceeds 15 bits") ). unchecked_flip_bit(U, I) = U `xor` (1u16 `unchecked_left_shift` cast_to_int(I)). bit_is_set(U, I) :- ( if I < 16u then unchecked_bit_is_set(U, I) else error($pred, "bit index exceeds 15 bits") ). unchecked_bit_is_set(U, I) :- U /\ (1u16 `unchecked_left_shift` cast_to_int(I)) \= 0u16. bit_is_clear(U, I) :- ( if I < 16u then unchecked_bit_is_clear(U, I) else error($pred, "bit index exceeds 15 bits") ). unchecked_bit_is_clear(U, I) :- U /\ (1u16 `unchecked_left_shift` cast_to_int(I)) = 0u16. %---------------------------------------------------------------------------% max_uint16 = 65_535_u16. %---------------------------------------------------------------------------% uint16_to_doc(U) = pretty_printer.uint16_to_doc(U). %---------------------------------------------------------------------------% :- end_module uint16. %---------------------------------------------------------------------------%