Migrate inline code to library call on demand

[spotlessmind1975]

Once put to work, the compiler proves to be inefficient from the point of view of the space occupied.

In fact, if we exclude the need to introduce portable mechanisms to differentiate the data memory banks from the code ones, the code itself is not very optimized in terms of size. It is therefore required to introduce an option (-e) to allow the use of embedded libraries instead of inline code.

Since this implies a deterioration in performance, every single function must be registered with a code, which must be indicated to suggest to the compiler to replace the inline code with a function call.

I.E.:

../ugbasic/ugbc/exe/ugbc.c64 -e cpumul8,cpufill -o main.prg main.bas

Where:

• cpumul8: use the embedded (library) version of cpu6502_fill instead of inline one
• cpufill: use the embedded (library) version of cpu6502_math_mul_8bit_to_16bit instead of inline one

[spotlessmind1975]

A first version was implemented for the CPU 6502, and the savings were about 10% compared to the size of the original executable. The scheme is to provide, for each function point, two versions of the same code: the first is the inline version (already coded) while the second is the embedded version.

By definition, the embedded have been activated for the following function points:

• embedded.cpu_fill_blocks
• embedded.cpu_fill
• cpu_math_div2_8bit
• cpu_math_mul_8bit_to_16bit
• cpu_math_div_8bit_to_8bit
• cpu_math_div2_const_8bit
• cpu_math_mul2_const_8bit
• cpu_math_mul_16bit_to_32bit
• cpu_math_div_16bit_to_16bit
• cpu_math_div_32bit_to_16bit
• cpu_random
• cpu_mem_move
• cpu_uppercase
• cpu_lowercase

The activity should be exentended to the remaining CPUs:

• [ ] Zilog Z80
• [ ] Motorola 6809