1. What are your surname and student number? [1]
Pat Terry, 63T0844
2. What do you understand by the term "half bootstrap of a compiler"? [3]
A half-bootstrap uses a self-resident compiler hosted on and targetting one computer to produce an
equivalent self-resident compiler hosted on and targeting another computer by first producing a cross-
compiler.
3. Suppose you have available the source code (CtoP.C) and object code (CtoP.P) for self compiling C compiler that targets a Pentium (P) computer. Complete the T diagrams below to show the steps you might follow in producing a self-compiling C compiler for the newly announced Septico computer. [4]
.--------------------------. .--------------------------.
| CtoS.C | | CtoS.P |
| C --------> S-code| | C ---------> S-code|
| | | |
`-------. .--------------------------. .-------'
| | CtoP.P | |
| C | C -------> Pentium | Pentium |
| | | |
`------------------. .------------------'
| | | |
Rewrite the back | | Pentium | | We get a cross
end of the CtoP | | | | compiler
compiler to | `----------' |
generate S-code | | Use this to
(do the coding of | | compile the
this in C). | | CtoS source
| .-----------------' again
v |
.--------------------------. | .--------------------------.
| CtoS.C | | | CtoS.S |
| C --------> S-code | | | C ---------> S-code|
| | v | |
`-------. .--------------------------. .-------'
| | CtoS.P | |
| C | C -------> S-code| S-Code |
| | | |
`------------------. .------------------'
| |
| Pentium | This is the final
| | executable required
`----------'
4. Self-compiling compilers have to be able to pass a self-consistency test. Depict this test by annotating the T diagram below as it would apply to your Septico C compiler. [2]
.--------------------------. .--------------------------.
| CtoS.C | | CtoS.S |
| C --------> S-Code | | C ---------> S-code |
| | | |
`-------. .--------------------------. .-------'
| | CtoS.S | |
| C | C -------> S-code | S-code |
| | | |
`------------------. .------------------'
| | ^
| S-code | | should be
| |<-----------' identical
`----------'
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