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Diffstat (limited to 'gcc/doc/extend.texi')
| -rw-r--r-- | gcc/doc/extend.texi | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index 76cc546fac6..0a1cdeb2abf 100644 --- a/gcc/doc/extend.texi +++ b/gcc/doc/extend.texi @@ -33,6 +33,7 @@ extensions, accepted by GCC in C89 mode and in C++. * Conditionals:: Omitting the middle operand of a @samp{?:} expression. * Long Long:: Double-word integers---@code{long long int}. * Complex:: Data types for complex numbers. +* Floating Types:: Additional Floating Types. * Decimal Float:: Decimal Floating Types. * Hex Floats:: Hexadecimal floating-point constants. * Zero Length:: Zero-length arrays. @@ -816,6 +817,37 @@ If the variable's actual name is @code{foo}, the two fictitious variables are named @code{foo$real} and @code{foo$imag}. You can examine and set these two fictitious variables with your debugger. +@node Floating Types +@section Additional Floating Types +@cindex additional floating types +@cindex @code{__float80} data type +@cindex @code{__float128} data type +@cindex @code{w} floating point suffix +@cindex @code{q} floating point suffix +@cindex @code{W} floating point suffix +@cindex @code{Q} floating point suffix + +As an extension, the GNU C compiler supports additional floating +types, @code{__float80} and @code{__float128} to support 80bit +(@code{XFmode}) and 128 bit (@code{TFmode}) floating types. +Support for additional types includes the arithmetic operators: +add, subtract, multiply, divide; unary arithmetic operators; +relational operators; equality operators; and conversions to and from +integer and other floating types. Use a suffix @samp{w} or @samp{W} +in a literal constant of type @code{__float80} and @samp{q} or @samp{Q} +for @code{_float128}. You can declare complex types using the +corresponding internal complex type, @code{XCmode} for @code{__float80} +type and @code{TCmode} for @code{__float128} type: + +@smallexample +typedef _Complex float __attribute__((mode(TC))) _Complex128; +typedef _Complex float __attribute__((mode(XC))) _Complex80; +@end smallexample + +Not all targets support additional floating point types. @code{__float80} +is supported on i386, x86_64 and ia64 targets and target @code{__float128} +is supported on x86_64 and ia64 targets. + @node Decimal Float @section Decimal Floating Types @cindex decimal floating types |