3ce38df8d1
Classical function call recursion wastes a lot of stack space. Each recursion level requires a full stack frame comprising all local variables and additional space as dictated by the processor calling convention. This implementation instead stores the variables that are unique for each recursion level in a parameter stack array, and uses iteration to emulate recursion. Function call recursion is not used until the array is full. To ensure the stack consumption isn't worsened by this design, the size of the parameter stack array is chosen to be similar to the stack frame excluding the array. Each function call recursion level can handle 8 iterative recursion levels. Stack consumption will worsen when sorting tiny arrays that do not need recursion (of 6 elements or less). It will be about equal for up to 15 elements, and be an improvement for larger arrays. The best case improvement is a stack size reduction down to about one quarter of the stack consumption before the change. A design where the parameter stack array is large enough for the worst case recursion level was rejected because it would worsen the stack consumption when sorting arrays smaller than about 1500 elements. The worst case is 31 levels on a 32-bit system. A design with a dynamic parameter array size was rejected because of limitations in some compilers.
README for GNU development tools This directory contains various GNU compilers, assemblers, linkers, debuggers, etc., plus their support routines, definitions, and documentation. If you are receiving this as part of a GDB release, see the file gdb/README. If with a binutils release, see binutils/README; if with a libg++ release, see libg++/README, etc. That'll give you info about this package -- supported targets, how to use it, how to report bugs, etc. It is now possible to automatically configure and build a variety of tools with one command. To build all of the tools contained herein, run the ``configure'' script here, e.g.: ./configure make To install them (by default in /usr/local/bin, /usr/local/lib, etc), then do: make install (If the configure script can't determine your type of computer, give it the name as an argument, for instance ``./configure sun4''. You can use the script ``config.sub'' to test whether a name is recognized; if it is, config.sub translates it to a triplet specifying CPU, vendor, and OS.) If you have more than one compiler on your system, it is often best to explicitly set CC in the environment before running configure, and to also set CC when running make. For example (assuming sh/bash/ksh): CC=gcc ./configure make A similar example using csh: setenv CC gcc ./configure make Much of the code and documentation enclosed is copyright by the Free Software Foundation, Inc. See the file COPYING or COPYING.LIB in the various directories, for a description of the GNU General Public License terms under which you can copy the files. REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info on where and how to report problems.