the worse x86 emitter ever seen

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pber

Joined: 23 Jul 2017
Posts: 24

pber 26 Jul 2017, 19:18

And it`s all mine!
Ladies and gentelemen, the source:

Code:

        c=1
        while c < 10000000 do
                c = c + 1
        end
        c

and its fasm translation (the funny part) :

Code:

        push ebx
        push ecx
        enter 4,0
        ;--------------- push const
        push dword 1
        ;--------------- setlocal c
        pop eax
        mov dword [ebp - 4], eax
        LOOP_START_1:
        ;--------------- mov_reg
        mov eax, [ebp - 4]
        
        ;--------------- mov_reg
        mov ecx, 10000000
        
        cmp eax, ecx
        jnl LOOP_END_1
        ;--------------- mov_reg
        mov eax, [ebp - 4]
        
        ;--------------- mov_reg
        mov ecx, 1
        
        ;--------------- addict
        add eax, ecx
        push eax
        ;--------------- setlocal c
        pop eax
        mov dword [ebp - 4], eax
        jmp LOOP_START_1
        LOOP_END_1:
        ;--------------- mov_reg
        mov eax, [ebp - 4]
        
        leave
        pop ecx
        pop ebx
        ret

Then, the output:

Code:

          00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
02BC7F38  53 51 C8 04 00 00 68 01 00 00 00 58 89 45 FC 8B
02BC7F48  45 FC B9 80 96 98 00 39 C8 7D 11 8B 45 FC B9 01
02BC7F58  00 00 00 01 C8 50 58 89 45 FC EB E3 8B 45 FC C9
02BC7F68  59 5B C3 -- -- -- -- -- -- -- -- -- -- -- -- --

10000000
----
time:   0.062

The timing includes:

+ loading of a modified (and super heavy) Lua 5.3
+ Lua`s loading of my AL (the asbtract language)
+ ...and the newest x86 emitter
+ obviously: the translation of the AST into fasm assembler
+ sending of the assembler source to FASM.DLL (linked into Lua)
+ the receiving of authentic and powerful machine code (...a myth!)
+ the minimal work WinXP had to do to make me happy!

I`m going to implement the JIT compiler
for an OO lang. It must allow me to recompile
methods and classes without stopping the whole system,
as happen in Smalltalk.

Hi all,
and hi Tomasz: thanks for your great work!

cheers
Paolo

26 Jul 2017, 19:18

guignol

Joined: 06 Dec 2008
Posts: 763

guignol 27 Jul 2017, 07:35

It's like at some point in life you actually start hatin' Roman languages

27 Jul 2017, 07:35

pber

Joined: 23 Jul 2017
Posts: 24

pber 27 Jul 2017, 08:27

I studied Roman: its similar to CommonLisp.

27 Jul 2017, 08:27

pber

Joined: 23 Jul 2017
Posts: 24

pber 28 Jul 2017, 20:49

...the second try does not use FASM.DLL but OLLY.DLL.

Now I can control each single opcode and re-implement my mini-assembler in Lua.
This version includes also some peep-hole optimizations.

The source:

Code:

        
                fmt = "<< %s %d >>\n"
                a = 0
                b = 3
                c = 1
                
                a = 123 * b
                s = "Hello world"
                while c<=4 do
                        printf(fmt, s, c)
                        c=c+1
                end

The dump:

Code:

01 [2AD1860].    53             push ebx        ; 
02 [2AD1861].    51             push ecx        ; 
03 [2AD1862].    C8 28 00 00            enter 28, 0     ; 
04 [2AD1866].    C7 C0 00 00 00 00              mov eax, 00h    ; 
05 [2AD186C].    C7 45 FC 98 18 AD 02           mov dword [ebp - 04h], 02AD1898h        ; !glob.str #1
06 [2AD1873].    C7 45 F8 A4 18 AD 02           mov dword [ebp - 08h], 02AD18A4h        ; !glob.str #2
07 [2AD187A].    C7 C0 7B 00 00 00              mov eax, 07Bh   ; 
08 [2AD1880].    89 45 F4               mov [ebp - 0Ch], eax    ; >a
09 [2AD1883].    50             push eax        ; 
10 [2AD1884].    8B 45 F8               mov eax, [ebp - 08h]    ; s>
11 [2AD1887].    50             push eax        ; 
12 [2AD1888].    8B 45 FC               mov eax, [ebp - 04h]    ; fmt>
13 [2AD188B].    50             push eax        ; 
14 [2AD188C].    E8 D9 FF 16 75         call 077C4186Ah ; call: printf
15 [2AD1891].    58             pop eax ; 
16 [2AD1892].    58             pop eax ; 
17 [2AD1893].    58             pop eax ; 
18 [2AD1894].    C9             leave   ; 
19 [2AD1895].    59             pop ecx ; 
20 [2AD1896].    5B             pop ebx ; 
21 [2AD1897].    C3             ret     ; 
23 [2AD1898]. global_001:        3C 3C 20 25 73 20 25 64 20 3E 3E 00            db '<< %s %d >>'        ; 
25 [2AD18A4]. global_002:        48 65 6C 6C 6F 20 77 6F 72 6C 64 00            db 'Hello world'        ;

The happiness:

Code:

<< Hello world 1 >>\n<< Hello world 2 >>\n<< Hello world 3 >>\n<< Hello world 4 >>\n>> 5

Ah ah...if it was C a back-slash plus one "n" could had been made a LF

bye bye
paolo

28 Jul 2017, 20:49

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