Re: Pascal Compiler

From: Greg King (
Date: 2004-12-13 18:54:23

From: Patrycjusz R. Łogiewa; on Date: December 13, 2004 05:57 AM -0500
> AFAIR, all the others mentioned here weren't really compiling BASIC into
> machine code, but rather into so-called "speedcodes". That (AFAIR, again)
> was something like calling BASIC routines for the given keywords rather
> than having the interpreter to read and interpret the tokens.
> Corrections to the above, anyone?

The speed-code output of the compilers is appended to a rather large
run-time module that interprets them, in the same way that the BASIC ROM
interprets BASIC tokens.  Those compiled programs run faster because
integer variables are combined directly by real integer operations, and
data is predigested:  during the compilation, PETSCII numbers are converted
into binary, the lengths of string-literals are measured, and the variables
tables are pre-built -- varible-names are replaced by offsets into those
tables.  The compiled program doesn't need to spend time creating and
looking for its data.

By the way, those compilers are recursively-built.  They are BASIC programs
which compiled themselves.

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