================ @@ -0,0 +1,116 @@ +<!--===- docs/Unsigned.md + + Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. + See https://llvm.org/LICENSE.txt for license information. + SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception + +--> + +# Fortran Extensions supported by Flang + +```{contents} +--- +local: +--- +``` + +For better compatibility with GNU Fortran and Sun Fortran, +this compiler supports an option (`-funsigned`) that enables +the `UNSIGNED` data type, constants, intrinsic functions, +its use with intrinsic operations and `SELECT CASE`, and C +language interoperability. + +## `UNSIGNED` type + +`UNSIGNED` is a numeric type with the same kinds as `INTEGER`. +It may appear as a type-spec in any context, including +a type declaration statement, a type-decl in an array +constructor or `ALLOCATE` statement, `IMPLICIT`, or a +function statement's prefix. + +`UNSIGNED` constants are nonempty strings of decimal digits +followed by the letter `U` and optionally a kind suffix with +an underscore. + +## `UNSIGNED` operations + +`UNSIGNED` operands are accepted for unary negation (`-`), +the basic four binary arithmetic intrinsic operations `+`, `-`, `*`, and `/`, +and for numeric relational operators. +The power operator `**` does not accept `UNSIGNED` operands. + +Mixed operations with other types are not allowed. +Mixed operations with one `UNSIGNED` operand and one BOZ literal +constant operand are allowed. +When the operands' kinds differ, the smaller operand is zero-extended +to the size of the larger. + +The arithmetic operations `u+v`, `-u`, `u-v`, and `u*v` are implemented +modulo `MAX(HUGE(u),HUGE(v))+1`; +informally speaking, they always truncate their results, or are +guaranteed to "wrap". + +## `UNSIGNED` intrinsic functions + +`UNSIGNED` operands are accepted as operands to, +or may be returned as results from, +several intrinsic procedures. + +Bitwise operations: +* `NOT` +* `IAND`, `IOR`, `IEOR`, `IBCLR`, `IBSET`, `IBITS`, `MERGE_BITS` +* `BTEST` +* `ISHFT`, `ISHFTC` +* `SHIFTA`, `SHIFTL`, `SHIFTR` +* `TRANSFER` +* `MVBITS` + +The existing unsigned comparisons `BLT`, `BLE`, `BGE`, and `BGT`. + +The inquiries `BIT_SIZE`, `DIGITS`, `HUGE`, and `RANGE`. + +Homogeneous `MAX` and `MIN`. ---------------- klausler wrote:
It means that `MAX` and `MIN` should support `UNSIGNED` arguments, but only when all of the arguments are `UNSIGNED`. Mixed arguments with `UNSIGNED` combined with `REAL` or other types should not work. https://github.com/llvm/llvm-project/pull/113504 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
