copt(1) 							z88 Development Kit							   copt(1)

NAME

       copt - peephole optimizer

SYSNOPIS

       copt file ...

DESCRIPTION

       copt  is a general-purpose peephole optimizer. It reads code from its standard input and writes an improved version to its standard output.
       copy reads the named files for its optimizations, which are encoded as follows:

		 <pattern for input line 1>
		 <pattern for input line 2>
		  ...
		 <pattern for input line n>
		 =
		 <pattern for output line 1>
		 <pattern for output line 2>
		  ...
		 <pattern for output line m>
		 <blank line>

       Pattern matching uses literal string comparison, with one exception: ``%%'' matches the ``%'' character, and  ``%''  followed  by  a  digit
       matches	everything  up to the next occurrence of the next pattern character, though all occurrences of %n must denote the same string. For
       example, the pattern ``%1=%1.'' matches exactly those strings that begin with a string X, followed by a ``='' (the first),  followed  by  a
       second occurrence of X, followed by a period. In this way, the input/output pattern

		 mov $%1,r%2
		 mov *r%2,r%2
		 =
		 mov %1,r%2

       commands copt to replace runs like

		 mov $_a,r3
		 mov *r3,r3

       with

		 mov _a,r3

       Note that a tab or newline can terminate a %n variable.

       copt  compares each run of input patterns with the current input instruction and its predecessors. If no match is found, it advances to the
       next input instruction and tries again. Otherwise, it replaces the input instructions with the corresponding output patterns, pattern vari-
       ables  instantiated,and	resumes  its search with the first instruction of the replacement. copt matches input patterns in reverse order to
       cascade optimizations without backing up.

BUGS

       Errors in optimization files are always possible.

SEE ALSO

       z88dk(1), z88dk-zcc(1), z88dk-z80asm(1), z88dk-appmake(1), z88dk-copt(1).

AUTHOR

       z88dk was written by Dominic Morris <dom@z88dk.org>, and others.

								 01 December 2009							   copt(1)