Thursday 23 June 2011

BASIC Assembler Update

Work continues on the BASIC assembler enhancements.   After spending some time learning how to use ObjAsm and the ROOL build tools effectively, the past week I've been suffering with a virus (of the human kind) which has slowed development to a crawl.

So far I've created a new optimised and assembler friendly version of all the pattern and lookup tables via ObjAsm macros in an automated fashion from the BASIC code.  This makes it easy to update them as I simply re-run the BASIC application.  The pains with the existing Acorn BASIC source code persist, so the plan is to add a branch from the existing code when a potential instruction begins with a "V" and branch back if no valid instruction is found.   All the new code is in several new source files to avoid creating problems in the existing code.  What remains then is to copy some code for storing the instruction into the correct location, and to figure out expression parsing to support the assembler syntax / notation discussed in the ROOL forums recently.

Unfortunately life is taking over for a while and it's going to slow down development.  It make take a little more time than expected get this one finished but it remains the highest priority task we are working on.