Here are a few examples to show what can be done with Disark.<\/p>\n\n\n\n
Original code:<\/p>\n\n\n\n
org #1000\n ld hl,Label1\n ld b,4\nLabel1\n djnz Label1\n ret<\/code><\/pre>\n\n\n\nOnce assembled with any assembler and disassembled with Disark:<\/p>\n\n\n\n
ld hl,4101 ;You can also ask for hex numbers!\n ld b,4\n djnz $\n ret <\/code><\/pre>\n\n\n\nNothing fancy here. Let’s continue, shall we…<\/p>\n\n\n\n
Generating labels<\/h4>\n\n\n\n org #1000\n ld hl,Label1\n ld b,4\nLabel1\n djnz Label1\n ret<\/code><\/pre>\n\n\n\n Once assembled and disassembled with Disark using the –genLabels<\/strong> and –src16bitValuesInHex<\/strong> (to have 16 bits number in hex) options: <\/p>\n\n\n\n ld hl,#1005\n ld b,4\nlab0005 djnz lab0005 ;This label is generated.\n ret <\/code><\/pre>\n\n\n\nThis is getting better…<\/p>\n\n\n\n
Using a symbol table<\/h3>\n\n\n\n
The real power of Disark is when the original source comes with a symbol table. Most formats can be understood, and you can indicate the “column” where to find the labels and address in the symbol table, via the –labelPositionInSymbolFile<\/strong> and –addressPositionInSymbolFile<\/strong>.<\/p>\n\n\n\nBy using a symbol table, you can recreate the original source code from the binary!<\/p>\n\n\n\n
org #1000 ;Original code.\nSTART ld bc,LABEL1\n ld hl,$\n ld de,LABEL1 + 3\nLABEL1 ld b,4\n djnz LABEL1\n jp START<\/code><\/pre>\n\n\n\nThe result is very close to the input! Check by yourself:<\/p>\n\n\n\n
org #1000 ;Generated via the \"--genOrg\" option.\nSTART ld bc,LABEL1\n ld hl,START+3 ;Disark choses the closest label.\n ld de,LABEL1+3\nLABEL1 ld b,4\n djnz LABEL1\n jp START<\/code><\/pre>\n\n\n\nThe command I used is:<\/p>\n\n\n\n
Disark <binary file to load> <z80 code to generate> --symbolFile <symbol file to load> --loadAddress 0x1000 --genOrg --src16bitValuesInHex<\/code><\/pre>\n\n\n\nBy using the loadAddress<\/strong> option, we define the entry point. This becomes necessary so that the symbol file matches the addresses of each instructions.<\/p>\n\n\n\nLabel semantics<\/h2>\n\n\n\n
So far the disassembled programs only consist in code. But what if you have bytes, word, even pointer areas? This is an example:<\/p>\n\n\n\n
org #1000\n\n ld ix,TABLE\n \nLABEL1 ld hl,0\nLABEL2 ld de,0\nLABEL3 ld bc,0\n \nTABLE\n dw LABEL1 ;Oops, how to reconstruct this??\n dw LABEL2\n dw LABEL3\n\nLEVELDATA\n db 1 ;Oops, how to reconstruct this??\n db 2\n db 3\n \nMUSICPERIODS\n dw 456 ;Oops, how to reconstruct this??\n dw 147\n dw 999<\/code><\/pre>\n\n\n\nDisark, just like any disassembler, has no idea that not everything is code. Without more information, Disark will produce this:<\/p>\n\n\n\n
org #1000\n ld ix,TABLE\nLABEL1 ld hl,#0\nLABEL2 ld de,#0\nLABEL3 ld bc,#0 ;So far, so good.\nTABLE inc b ;ARG! No! This was \"db 1\"!\n djnz MUSICPERIODS+1\n djnz MUSICPERIODS+6\nLEVELDATA equ $+1 ;ARG! Our LevelData area is compromised too!\n djnz LEVELDATA+2\n ld (bc),a\n inc bc\nMUSICPERIODS ret z ;ARG! This is not good!\n ld bc,#93\n rst 32\n inc bc\n<\/code><\/pre>\n\n\n\n Ok, this is bad. But do not worry, there is a solution. Disark manages all this via Label semantics<\/strong>! The original source<\/strong> can contain labels <\/strong>indicating how to reconstruct it faithfully. These labels must have a specific format so that Disark can locate them in the symbol table<\/em>. They can be added a prefix, and must be added a suffix. Some examples:<\/p>\n\n\n\nCode region:<\/h4>\n\n\n\n
These are default, so you shouldn’t need to declare them.<\/p>\n\n\n\n
DisarkCodeRegionStart a code region starts here.\nDisarkCodeRegionEnd a code region ends here.<\/code><\/pre>\n\n\n\nByte region:<\/h4>\n\n\n\nDisarkByteRegionStart a code region starts here.\nDisarkByteRegionEnd a code region ends here.<\/code><\/pre>\n\n\nExample of use:<\/p>\n\n\n
org #1000\n ld hl,#1234\n jr AFTER_STUFF\nMyDemo_DisarkByteRegionStart_Stuff ;Declares a byte area...\n db 1, 2, 3, 4, 5, 6, 7\n db 8, 9, 10, 11, #ff\nMyDemo_DisarkByteRegionEnd_Stuff ;...that ends here!\nAFTER_STUFF\n ld de,#4567\n ret<\/code><\/pre>\n\n\n\nAnd the result is:<\/p>\n\n\n\n
org #1000\n ld hl,#1234\n jr AFTER_STUFF\n db 1\n db 2\n db 3\n db 4\n db 5\n db 6\n db 7\n db 8\n db 9\n db 10\n db 11\n db 255\nAFTER_STUFF ld de,#4567\n ret <\/code><\/pre>\n\n\n\nYES! Now the code is perfectly regenerated! Note how the Disark marker labels have been removed from the disassembled source. They are not needed in the code anymore!<\/p>\n\n\n\n
Word region and Pointer region:<\/h4>\n\n\n\nDisarkWordRegionStart ;A word region starts here.\nDisarkWordRegionEnd ;A word region ends here.\nDisarkPointerRegionStart ;A pointer region starts here.\nDisarkPointerRegionEnd ;A pointer region ends here.<\/code><\/pre>\n\n\n\nBut what is the difference between Word and Pointer region? No reference will be inferred (i.e. “guessed”) from the Word region, but they will from the Pointer region. In the example above, music periods must stay “as-is” and not converted to a pointer, else relocating the code will also modify your music periods!<\/p>\n\n\n\n