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## Risa and Asir

Risa is the name of whole libraries of a computer algebra system which is under development at FUJITSU LABORATORIES LIMITED. The structure of Risa is as follows.

- The basic algebraic engine
  This is the part which performs basic algebraic operations, such as arithmetic operations, to algebraic objects, e.g., numbers and polynomials, which are already converted into internal forms. It exists, like ``libc.a'` of UNIX, as a library of ordinary UNIX system. The algebraic engine is written mainly in C language and partly in assembler. It serves as the basic operation part of Asir, a standard language interface of Risa.
- Memory Manager
  Risa employs, as its memory management component (the memory manager), a free software distributed by Boehm (`gc-6.1alpha5`). It is proposed by `[Boehm,Weiser]`, and developed by Boehm and his colleagues. The memory manager has a memory allocator which automatically reclaims garbages, i.e., allocated but unused memories, and refreshes them for further use. The algebraic engine gets all its necessary memories through the memory manager.
- Asir
  Asir is a standard language interface of Risa's algebraic engine. It is one of the possible language interfaces, because one can develop one's own language interface easily on Risa system. Asir is an example of such language interfaces. Asir has very similar syntax and semantics as C language. Furthermore, it has a debugger that provide a subset of commands of `dbx`, a widely used debugger of C language.

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