Symbol Names
============

   Symbol names begin with a letter or with one of `_.' (On most
machines, you can also use `$' in symbol names; exceptions are noted in
See Machine Dependent.) That character may be followed by any
string of digits, letters, dollar signs (unless otherwise noted in
See Machine Dependent), and underscores.  Case of letters is
significant: `foo' is a different symbol name than `Foo'.

   For the AMD 29K family, `?' is also allowed in the body of a symbol
name, though not at its beginning.

   Each symbol has exactly one name. Each name in an assembly language
program refers to exactly one symbol. You may use that symbol name any
number of times in a program.

Local Symbol Names
------------------

   Local symbols help compilers and programmers use names temporarily.
There are ten local symbol names, which are re-used throughout the
program.  You may refer to them using the names `0' `1' ... `9'.  To
define a local symbol, write a label of the form `N:' (where N
represents any digit).  To refer to the most recent previous definition
of that symbol write `Nb', using the same digit as when you defined the
label.  To refer to the next definition of a local label, write
`Nf'--where N gives you a choice of 10 forward references.  The `b'
stands for "backwards" and the `f' stands for "forwards".

   Local symbols are not emitted by the current GNU C compiler.

   There is no restriction on how you can use these labels, but
remember that at any point in the assembly you can refer to at most 10
prior local labels and to at most 10 forward local labels.

   Local symbol names are only a notation device.  They are immediately
transformed into more conventional symbol names before the assembler
uses them.  The symbol names stored in the symbol table, appearing in
error messages and optionally emitted to the object file have these
parts:

`L'
     All local labels begin with `L'. Normally both `as' and `ld'
     forget symbols that start with `L'. These labels are used for
     symbols you are never intended to see.  If you give the `-L'
     option then `as' will retain these symbols in the object file. If
     you also instruct `ld' to retain these symbols, you may use them
     in debugging.

`DIGIT'
     If the label is written `0:' then the digit is `0'.  If the label
     is written `1:' then the digit is `1'.  And so on up through `9:'.

`C-A'
     This unusual character is included so you don't accidentally invent
     a symbol of the same name.  The character has ASCII value `\001'.

`*ordinal number*'
     This is a serial number to keep the labels distinct.  The first
     `0:' gets the number `1'; The 15th `0:' gets the number `15';
     *etc.*.  Likewise for the other labels `1:' through `9:'.

   For instance, the first `1:' is named `L1C-A1', the 44th `3:' is
named `L3C-A44'.