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Diffstat (limited to 'doc/nasmdoc.src')
| -rw-r--r-- | doc/nasmdoc.src | 62 |
1 files changed, 47 insertions, 15 deletions
diff --git a/doc/nasmdoc.src b/doc/nasmdoc.src index 7128b51..58db312 100644 --- a/doc/nasmdoc.src +++ b/doc/nasmdoc.src @@ -1445,10 +1445,12 @@ Some examples: \S{chrconst} \i{Character Constants} A character constant consists of up to four characters enclosed in -either single or double quotes. The type of quote makes no -difference to NASM, except of course that surrounding the constant -with single quotes allows double quotes to appear within it and vice -versa. +either single quotes (\c{'...'}), double quotes (\c{"..."}) or +backquotes (\c{`...`}). Single or double quotes are equivalent to +NASM (except of course that surrounding the constant with single +quotes allows double quotes to appear within it and vice versa); the +contents of those are represented verbatim. Strings enclosed in +backquotes support C-style \c{\\}-escapes for special characters. A character constant with more than one character will be arranged with \i{little-endian} order in mind: if you code @@ -1462,6 +1464,31 @@ the sense of character constants understood by the Pentium's \i\c{CPUID} instruction. \# (see \k{insCPUID}) +The following escape sequences are recognized by backquoted strings: + +\c \' single quote (') +\c \" double quote (") +\c \` backquote (`) +\c \\\ backslash (\) +\c \? question mark (?) +\c \a BEL (ASCII 7) +\c \b BS (ASCII 8) +\c \n LF (ASCII 10) +\c \v VT (ASCII 11) +\c \f FF (ASCII 12) +\c \r CR (ASCII 13) +\c \e ESC (ASCII 27) +\c \377 Up to 3 octal digits - ASCII literal +\c \xFF Up to 2 hexadecimal digits - ASCII literal +\c \u1234 4 hexadecimal digits - Unicode character +\c \U12345678 8 hexadecimal digits - Unicode character + +All other escape sequences are reserved. Note that \c{\\0}, meaning a +\c{NUL} character, is a special case of the octal escape sequence. + +Unicode characters specified with \c{\\u} or \c{\\U} are converted to +UTF-8. + \S{strconst} String Constants @@ -2165,17 +2192,22 @@ assigned the value of 9. Individual letters in strings can be extracted using \c{%substr}. An example of its use is probably more useful than the description: -\c %substr mychar 'xyz' 1 ; equivalent to %define mychar 'x' -\c %substr mychar 'xyz' 2 ; equivalent to %define mychar 'y' -\c %substr mychar 'xyz' 3 ; equivalent to %define mychar 'z' - -In this example, mychar gets the value of 'y'. As with \c{%strlen} -(see \k{strlen}), the first parameter is the single-line macro to -be created and the second is the string. The third parameter -specifies which character is to be selected. Note that the first -index is 1, not 0 and the last index is equal to the value that -\c{%strlen} would assign given the same string. Index values out -of range result in an empty string. +\c %substr mychar 'xyzw' 1 ; equivalent to %define mychar 'x' +\c %substr mychar 'xyzw' 2 ; equivalent to %define mychar 'y' +\c %substr mychar 'xyzw' 3 ; equivalent to %define mychar 'z' +\c %substr mychar 'xyzw' 2,2 ; equivalent to %define mychar 'yz' +\c %substr mychar 'xyzw' 2,-1 ; equivalent to %define mychar 'yzw' +\c %substr mychar 'xyzw' 2,-2 ; equivalent to %define mychar 'yz' + +As with \c{%strlen} (see \k{strlen}), the first parameter is the +single-line macro to be created and the second is the string. The +third parameter specifies the first character to be selected, and the +optional fourth parameter preceeded by comma) is the length. Note +that the first index is 1, not 0 and the last index is equal to the +value that \c{%strlen} would assign given the same string. Index +values out of range result in an empty string. A negative length +means "until N-1 characters before the end of string", i.e. \c{-1} +means until end of string, \c{-2} until one character before, etc. \H{mlmacro} \i{Multi-Line Macros}: \I\c{%imacro}\i\c{%macro} |