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flat assembler > Projects and Ideas > the worse x86 emitter ever seen

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pber



Joined: 23 Jul 2017
Posts: 4

the worse x86 emitter ever seen

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 ecx10000000
        
        cmp eaxecx
        jnl LOOP_END_1
        ;--------------- mov_reg
        mov eax, [ebp - 4]
        
        ;--------------- mov_reg
        mov ecx1
        
        ;--------------- addict
        add eaxecx
        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
Post 26 Jul 2017, 19:18
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guignol



Joined: 06 Dec 2008
Posts: 267

It's like at some point in life you actually start hatin' Roman languages
Post 27 Jul 2017, 07:35
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pber



Joined: 23 Jul 2017
Posts: 4

I studied Roman: its similar to CommonLisp.
Post 27 Jul 2017, 08:27
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pber



Joined: 23 Jul 2017
Posts: 4

...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(fmtsc)
                        c=c+1
                end



The dump:

Code:

01 [2AD1860].    53             push ebx        
02 [2AD1861].    51             push ecx        
03 [2AD1862].    C8 28 00 00            enter 280     
04 [2AD1866].    C7 C0 00 00 00 00              mov eax00h    
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 eax07Bh   
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
Post 28 Jul 2017, 20:49
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