https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93727
Bug ID: 93727
Summary: Fortran 2018: EX edit descriptor
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: libfortran
Assignee: unassigned at gcc dot gnu.org
Reporter: thenlich at gcc dot gnu.org
Target Milestone: ---
13.7.2.3.6 EX editing
1 The EX edit descriptor produces an output field in the form of a
hexadecimal-significand number.
2 The EXw.d and EXw.dEe edit descriptors indicate that the external field
occupies w positions, except when w is zero in which case the processor selects
the field width. The fractional part of the field contains d hexadecimal
digits, except when d is zero in which case the processor selects the number of
hexadecimal digits to be the minimum required so that the output field is equal
to the internal value; d shall not be zero if the radix of the internal value
is not a power of two. The hexadecimal point, represented by a decimal symbol,
appears after the first hexadecimal digit. For the form EXw.d, and for EXw.dE0,
the exponent part contains the minimum number of digits needed to represent the
exponent; otherwise the exponent contains e digits. The e has no effect on
input. The scale factor has no effect on output.
3 The form and interpretation of the input field is the same as for Fw.d
editing (13.7.2.3.2).
4 For an internal value that is an IEEE infinity or NaN, the form of the output
field is the same as for Fw.d.
5 For an internal value that is neither an IEEE infinity nor a NaN, the form of
the output field is
[ ± ] 0X x0 . x1x2 . . . exp
where:
• ± signifies a plus sign or a minus sign;
• . signifies a decimal symbol (13.6);
• x0x1x2 . . . are the most significant hexadecimal digits of the internal
value, after rounding if d is not zero (13.7.2.3.8);
• exp is a binary exponent expressed as a decimal integer; for EXw.d and
EXw.dE0, the form is P ±z1 . . . zn20 , where n is the minimum number of digits
needed to represent exp, and for EXw.dEe with e greater than zero the form is P
±z1 . . . ze22 . The choice of binary exponent is processor dependent. If the
most significant binary digits of the internal value are b0b1b2 . . ., the
binary exponent might make the value of x0 be that of b0, b0b1, b0b1b2, or
b0b1b2b3. A plus sign is produced if the exponent value is zero.
Examples:
Internal value Edit descriptor Possible output with SS in effect
1.375 EX0.1 0X1.6P+0
−15.625 EX14.4E3 -0X1.F400P+003
1048580.0 EX0.0 0X1.00004P+20
2.375 EX0.1 0X2.6P+0
