Assembler Optimizer

Hello santiontanon,

I don't know if your optimizer uses this (time and size) optimization:

ld a,r  ;  5
neg     ; 10

transformed into:

xor a   ; 5
sub a,r ; 5

Just a suggestion, if it's not already taken into account.

It had been a while since I made a new release, so, I just released version 2.5 in GitHub: https://github.com/santiontanon/mdlz80optimizer/releases/tag...

The new version contains many many small improvements and fixes here and there (things that I needed), but the two main new additions are:
- support for the WLA-DX assembler (common in the console development world)
- a new "code execution" functionality which is useful to optimize code without having to get it into an emulator/system to measure its execution.

I find this last functionality very useful, and I have been using it a lot in a project I am working on that is not for MSX, and hence all the fancy features of openMSX are not available. For example, imagine you have this simple code:

    org #4000

start:
    ld hl,table
    ld de,#c000
    ld bc,4
    ldir
end:

table:
    db 0,1,2,3

You can call mdl like this (telling MDL to start executing at "start", and stop once the PC reaches "end"):

java -jar mdl.jar test.asm -e:u start end

And you will get this as output:

INFO: Execution result:
INFO:   f: 32 (#20)
INFO:   d: 192 (#c0)
INFO:   e: 4 (#04)
INFO:   h: 64 (#40)
INFO:   l: 15 (#0f)
INFO:   r: 4 (#04)
INFO:   (#c000) = 0 (#00)
INFO:   (#c001) = 1 (#01)
INFO:   (#c002) = 2 (#02)
INFO:   (#c003) = 3 (#03)
INFO:   4 instructions executed.
INFO:   execution time: 120 t-states

As you can see if shows everything that changed (registers and memory). Perhaps, I should also add which flags changed?

Naturally, you can change the z80 type. By default it uses an MSX-configured z80, but if you use "-cpu z80", then executio only takes 109 t-states (e.g., on a Spectrum), and if you say "-cpu z80cpc", you get "32 nops" (As time in the Amstrad CMC is measured in "nops").

Anyway, I find it very useful to check small routines :)

but, "END" is an assembler command that tells it to shove it. I would expect "label table not found" error or something.

A few days ago I was optimizng some code and possibly found a new pattern for the Assembler Optimizer.

The code looked like that:

	LD	(IX+00h),20h			; 
	LD	(IX+01h),20h
	LD	(IX+18h),20h
	LD	(IX+19h),20h

	LD	BC,00h - 18h * 18h
	ADD	IX,BC

	LD	(IX+00h),20h			; 
	LD	(IX+01h),20h
	LD	(IX+18h),20h
	LD	(IX+19h),20h

Obviously, it was a bad code.

So optimization would be something like that:

LD A,20h, and replace all LD (IX+??),20h to LD (IX+??),A

But it should save register A if after working with IX register A is not refined and not save it if registerA has been changed without usage.

Mmm, can this optimise the code generated by the msx ascii C compiler?