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doc: document the %num() function

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Add documentation for the %num() preprocessor function.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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H. Peter Anvin 2022-11-15 17:12:25 -08:00
parent 1d1ba9c7d7
commit e7dd0e8e3f
1 changed files with 31 additions and 4 deletions
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@ -2255,6 +2255,17 @@ and \i{detokenization} are performed for the arguments of the
directives.
\S{pcdirect} \i{Directives} processing
Remaining preprocessor \i{directives} are processed. It is specific
to each directive to what extend the above expansions or the ones
specified in \k{pcfinal} are performed on their arguments.
It is specific to each directive to what extent \i{inline expansions}
and \i{detokenization} are performed for the arguments of the
directives.
\S{pcsmacro} \i{Inline expansions} and other \I{preprocessor directives}directives
In this step, the following expansions are performed on each line:
@ -2276,10 +2287,6 @@ below), the parameters to that macro are expanded at this time. See
\b \i{Macro-local labels} are converted into unique strings, see
\k{maclocal}.
\b Remaining preprocessor \i{directives} are processed. It is specific
to each directive to what extend the above expansions or the ones
specified in \k{pcfinal} are performed on their arguments.
\S{pcmmacro} \i{Multi-Line Macro Expansion}
@ -2923,6 +2930,26 @@ argument to the conditional using \c{\{\}}:
\c %endif
\S{f_num} \i\c{%num()} Function
The \c{%num()} function evaluates its arguments as expressions, and
then produces a quoted string encoding the first argument as an
\e{unsigned} integer. The second argument is the encoding base (from 2
to 64, default 10) and the third argument is the desired number of
digits (max 253, default -1).
Only the first argument is required.
If the number of digits is negative, NASM will add additional digits
if needed, if positive the string is truncated to the number of digits
specified. 0 is treated as -1, except that the input number 0
generates an empty string (thus, the first digit will never be zero.)
The full 64-symbol set used is, in order:
\c 0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ@_
\S{f_sel} \i\c{%sel()} Function
The \c{%sel()} function evaluates its first argument as an