--------------------------------------------------------------ASM6f (v1.6; modifications v03)A 6502 assembler by loopy (loopy at mm.st)With modifications by freem, nicklausw, Sour, controllerhead, dttdndn, and morskoyzmey--------------------------------------------------------------ASM6f is a fork of ASM6, primarily targeted at NES/Famicom development.--------------------------------------------------------------Features compared to stock ASM6--------------------------------------------------------------* Support for some illegal/undocumented opcodes.  (Note: Support for unstable opcodes requires use of directives.)* Code from sonder's fork of ASM6 to allow output of FCEUX-compatible .nl files.* Output of Lua-compatible symbol files.* New directives "IGNORENL" and "ENDINL".  These two are used for ignoring certain defines when using the -n option.* Support for iNES original and 2.0 header insertion.* Output of .cdl files, for use with FCEUX/Mesen.* Output of Mesen-compatible symbol files (both old and new formats).* Generic +/- labels do not break @local scope.* Support for a: prefix to force absolute addressing for zero-page addresses.* Absolute addressing support for zero page addresses.--------------------------------------------------------------Command line--------------------------------------------------------------Usage:        asm6f [-options] sourcefile [outputfile] [listfile]Options:        -?         Show some help        -l         Create listing        -L         Create verbose listing (expand REPT, MACRO)        -d<name>:  Define a symbol and make it equal to 1        -q         Quiet mode (suppress all output unless there's an error)        -n         export FCEUX-compatible .nl files        -f         export Lua symbol file        -c         export .cdl for use with FCEUX/Mesen        -m         export new format Mesen label file (.mlb)        -M         export old format Mesen label file (.mlb)        Default output is <sourcefile>.bin        Default listing is <sourcefile>.lstRight now, everything else is the same as the original ASM6, so check outreadme-original.txt for more information.--------------------------------------------------------------Supported Undocumented Opcodes--------------------------------------------------------------asm6f supports the use of a number of undocumented/"illegal" opcodes.Unstable opcodes require the use of the "UNSTABLE" and/or "HUNSTABLE"directives, or an error will be thrown.Information about these opcodes was sourced from Graham's 6502 Opcode document:http://www.oxyron.de/html/opcodes02.html[Normal]These opcodes appear to be "safe" to use.The alternate $EB opcode for sbc #{immediate} is not supported.slo (Shift Left, Or)        slo {addrmode} = asl {addrmode} + ora {addrmode}        Known as "aso" in other undocumented opcode sources.rla (Rol Left, And)        rla {addrmode} = rol {addrmode} + and {addrmode}sre (Shift Right, Exclusive or)        sre {addrmode} = lsr {addrmode} + eor {addrmode}        Known as "lse" in other undocumented opcode sources.rra (Ror Right, Add with carry)        rra {addrmode} = ror {addrmode} + adc {addrmode}sax (Store A&X)        sax {addrmode} = store A&X into {addrmode}        "The A&X operation is a result of A and X put onto the bus        at the same time."lax (Load A&X)        lax {addrmode} = lda {addrmode} + ldx {addrmode}dcp (Decrement, ComPare)        dcp {addrmode} = dec {addrmode} + cmp {addrmode}isc (Increment, Subtract with Carry)        isc {addrmode} = inc {addrmode} + sbc {addrmode}        Known as "isb" in other undocumented opcode sources.anc        anc #{immediate} = and #{immediate} + (asl)        "this command performs an AND operation only, but bit 7 is put into        the carry, as if the ASL/ROL would have been executed."alr (And Left Rotate)        alr #{immediate} = and #{immediate} + (rol)        Known as "asr" in other undocumented opcode sources.arr        arr #{immediate} = and #{immediate} + lsr        "Part of this command are some ADC mechanisms. Following effects appear        after AND but before ROR: the V-Flag is set according to (A and #{imm})+#{imm},        bit 0 does NOT go into carry, but bit 7 is exchanged with the carry."axs (A&X, Subtract immediate)        axs #{immediate} = A&X minus #{immediate} into X        Known as "sbx" in other undocumented opcode sources. (Groepaz's doc)        "Performs CMP and DEX at the same time, so that the MINUS sets the flag        like CMP, not SBC."las        las {addrmode} = Stores {addrmode}&S into A,X,S.        Known as "lar" in other undocumented opcode sources.        One source (which?) calls las "probably unreliable".[Unstable]"unstable in certain matters"; requires UNSTABLE directive.ahx (A&H&X)        ahx {addrmode} = stores A&X&H into {addrmode}        "Sometimes the &H drops off. Page boundary crossing will not work as        expected; the bank where the value is stored may not be equal to the        value stored."shy (Store H&Y)        shy {addrmode} = stores Y&H into {addrmode}        "Sometimes the &H drops off. Page boundary crossing will not work as        expected; the bank where the value is stored may not be equal to the        value stored."shx (Store H&X)        shx {addrmode} = stores X&H into {addrmode}        "Sometimes the &H drops off. Page boundary crossing will not work as        expected; the bank where the value is stored may not be equal to the        value stored."tas        tas {addrmode} = Stores A&X into S, A&X&H into {addrmode}[Highly Unstable]"DO NOT USE!!!", "results are not predictable on some machines".YOU HAVE BEEN WARNED.requires HUNSTABLE directive.xaa (X And A) HIGHLY UNSTABLE!!!        xaa #{immediate} = X&#{immediate}        Known as "ane" in other undocumented opcode sources. (Groepaz's doc)lax is currently not supported.--------------------------------------------------------------Assembler directive clarifications--------------------------------------------------------------INCLUDE/INCSRCINCBIN/BIN        Filenames can be double-quoted, permitting names that contain        spaces, ex.:                INCLUDE "some file.bin"                INCBIN "some file.bin"                INCBIN "some file.bin", $400                INCBIN "some file.bin", $200, $2000--------------------------------------------------------------Additional assembler directives--------------------------------------------------------------IGNORENL/ENDINL        Suppresses output of any labels when exporting FCEUX .nl files.        Useful for defining labels that may conflict with zero page addresses.                ; don't show these button masks in the .nl file                IGNORENL                PAD_A      = %10000000                PAD_B      = %01000000                PAD_SELECT = %00100000                PAD_START  = %00010000                PAD_UP     = %00001000                PAD_DOWN   = %00000100                PAD_LEFT   = %00000010                PAD_RIGHT  = %00000001                ENDINLUNSTABLE        Enables use of somewhat unstable 6502 opcodes.                ; use some unstable undocumented instructions                ldy #0                ldx #1                ahx example,y                shy example,x                shx example,y                tas example,yHUNSTABLE        Enables use of highly unstable 6502 opcodes.                ; throw caution to the wind and use xaa                HUNSTABLE                xaa #7--------------------------------------------------------------iNES directives--------------------------------------------------------------Note that using an iNES header is optional; it's only insertedif at least one of these following directives is used.INESPRG x        Number of PRG ROM banks in a NES ROM.INESCHR x        Number of CHR ROM banks in a NES ROM.INESMAP x        Mapper number of NES ROM.INESMIR x        Mirroring mode of a NES ROM.NES2CHRRAM x        Amount of CHR RAM used by a NES ROM.NES2PRGRAM x        Amount of PRG RAM used by a NES ROM.NES2SUB x        Submapper number of NES ROM.NES2TV x        TV mode of NES ROM: NTSC, PAL, or both (0, 1 or 2) ('N', 'P' or 'B')NES2VS        Sets ROM to use the Vs. Unisystem.NES2BRAM x        Amount of battery-packed PRG RAM in NES ROM.NES2CHRBRAM x        Amount of battery-packed CHR RAM in NES ROM.--------------------------------------------------------------loopy's original To-Do List--------------------------------------------------------------//todo - do NOT open source files in update mode, since we do not want to modify them in any way//todo - don't open text files in binary mode//todo - thoroughly verify operation on big-endian machine//todo - avoid putting special values into pointers, like (char*)1//todo - don't depend on platform supporting unaligned objects//todo - make everything static//todo - redundant parsing code is all over the place, try clean it up / consolidate--------------------------------------------------------------freem's To-Do List--------------------------------------------------------------* add .undef? (could react badly on other passes)* Allow -d option to set the symbols to a specific value instead of 1?* Ignore defines from command line when using -n* add ca65 debug format for NintendulatorDX--------------------------------------------------------------<EOF>