64tass(1)

✨ 64tass(1) ✨

Bestie, this is the manual page for 64tass 🎀 The manual name is 64tass, and this guide covers version 1.60 💖

✨ NAME ✨

okay so 64tass is a multi pass optimizing macro assembler for the 65xx series of processors 🧚 literally the cutest little assembler 💅

🎀 SYNOPSIS 🎀

here's how you call it 💜

64tass [OPTION]... [SOURCES]...

🌸 DESCRIPTION 🌸

64tass is a cross assembler that targets the 65xx series of micro processors 🔥 this page is only going over the command line options 🙈 all the many features are in the HTML manual, so go check that out if you want the full tea ☕

👑 OPTIONS 👑

🦋 Output options 🦋

• -o filename, --output filename — Puts the output into filename 💖 The default output filename is 'a.out', and this option changes it. You can use it more than once. The format sticks around, but the section and memory map file go back to global after each file.
• --output-append filename — Appends to the output file instead of overwriting it 🫶
• --no-output — Same as the output option, but no file will be written 🙈
• --map filename — Places the memory map into filename instead of displaying it 🗺️
• --map-append filename — Appends the memory map to a file instead of displaying it ✨
• --no-map — The memory map won't be displayed or recorded 💀
• --output-section sectionname — Outputs this section instead of everything 🍓
• --output-exec expression — Sets the execution address for output formats that support this 👑
• -X, --long-address — Uses 3 byte address/length for CBM and nonlinear output instead of 2 bytes 💅 It also bumps the size of raw output up to 16 MiB.
• --cbm-prg — Generates CBM format binaries, and this is the default 🌈 The first 2 bytes are the little endian address of the first valid byte (start address). Overlapping blocks get flattened, and uninitialized memory is filled up with zeros. Uninitialized memory before the first and after the last valid bytes is not saved. Up to 64 KiB, or 16 MiB with long address.
• -b, --nostart — Outputs raw data only, with no start address 🧃 Overlapping blocks get flattened, and uninitialized memory is filled up with zeros. Uninitialized memory before the first and after the last valid bytes is not saved. Up to 64 KiB, or 16 MiB with long address.
• -f, --flat — Flat address space output mode 🦋 Overlapping blocks get flattened, and uninitialized memory is filled up with zeros. Uninitialized memory after the last valid byte is not saved. Up to 4 GiB.
• -n, --nonlinear — Generates a nonlinear output file 🌸 Overlapping blocks get flattened. Blocks are saved in sorted order, and uninitialized memory is skipped. Up to 64 KiB, or 16 MiB with long address.
• --atari-xex — Generates an Atari XEX output file 🕹️ Overlapping blocks are kept, and continuing blocks are concatenated. Saving happens in the definition order without sorting, and uninitialized memory is skipped in the output. Up to 64 KiB.
• --apple-ii — Generates an Apple II output file (DOS 3.3) 🍎 Overlapping blocks get flattened, and uninitialized memory is filled up with zeros. Uninitialized memory before the first and after the last valid bytes is not saved. Up to 64 KiB.
• --c256-pgx — Generates a C256 Foenix PGX output file 💜 Overlapping blocks get flattened, and uninitialized memory is filled up with zeros. Uninitialized memory before the first and after the last valid bytes is not saved. Up to 16 MiB.
• --c256-pgz — Generates a C256 Foenix PGZ output file 🌷 Overlapping blocks get flattened. Blocks are saved in sorted order, and uninitialized memory is skipped. Up to 16 MiB.
• --cody-bin — Generates a Cody binary output file 🧁 Overlapping blocks get flattened, and uninitialized memory is filled up with zeros. Uninitialized memory before the first and after the last valid bytes is not saved. Up to 64 KiB.
• --wdc-bin — Generates a WDC binary output file, also known as zardoz binary 🌀 Overlapping blocks get flattened. Blocks are saved in sorted order, and uninitialized memory is skipped. Up to 16 MiB.
• --intel-hex — Uses the Intel HEX output file format 🔌 Overlapping blocks are kept, data is stored in the definition order, and uninitialized areas are skipped. I8HEX goes up to 64 KiB, and I32HEX goes up to 4 GiB.
• --s-record — Uses the Motorola S-record output file format 💫 Overlapping blocks are kept, data is stored in the definition order, and uninitialized memory areas are skipped. S19 goes up to 64 KiB, S28 up to 16 MiB, and S37 up to 4 GiB.

💅 Operation options 💅

• -a, --ascii — Uses ASCII/Unicode text encoding instead of raw 8-bit 📝 Normally no conversion takes place. This is for backwards compatibility with a DOS based Turbo Assembler editor, which could create PETSCII files for 6502tass. (control characters included, of course) Using this option changes the default 'none' and 'screen' encodings so they map 'a'-'z' and 'A'-'Z' into the correct PETSCII range of $41-$5A and $C1-$DA, which is way more suitable for an ASCII editor. It also adds predefined petcat style PETSCII literals to the default encodings, and enables Unicode letters in symbol names. For writing sources in UTF-8/UTF-16 encodings this option is required! 😭
• -B, --long-branch — Automatic BXX *+5 JMP xxx 🔁 "Branch too long" messages can be so annoying, and they usually need rewriting to BXX *+5 JMP xxx. 64tass can do this for you if you use this option. But BRA is not converted.
• -C, --case-sensitive — Makes all symbols (variables, opcodes, directives, operators, etc.) case sensitive 🧐 Otherwise everything is case insensitive by default.
• -D label=value — Defines a label to a value 🎯 Same syntax is allowed as in source files. Be careful with string quoting, the shell might eat some of the characters!
• -q, --quiet — Suppresses messages 🤫 Disables the header and summary messages.
• -T, --tasm-compatible — Enables TASM compatible operators and precedence 🕰️ This switches the expression evaluator into compatibility mode. It enables the '.', ':' and '!' operators, and disables 64tass specific extensions, disables precedence handling, and forces 16 bit unsigned evaluation (see 'differences to original Turbo Assembler' below).
• -I path — Specifies the include search path 🗂️ If an included source or binary file can't be found in the directory of the source file, this path gets tried. You can specify more than one directory by repeating this option. If multiple matches exist, the first one is used.
• -M file, --dependencies file — Specifies the make rule output file 🧩 Writes a dependency rule suitable for 'make' from the list of files used during compilation.
• --dependencies-append file — Appends to the dependencies file instead of overwriting it ➕
• --make-phony — Enables phony target generation for dependencies 👻

🧚 Diagnostic options 🧚

• -E file, --error file — Specifies the error output file 🚨 Normally compilation errors are written to the standard error output. You can redirect them to a file, or to the standard output, by using '-' as the file name.
• --error-append file — Appends to the error file instead of overwriting it 📎
• --no-error — Doesn't output any errors, just counts them 🔢
• -w, --no-warn — Suppresses warnings 🔕 Disables warnings during compile. Finer grained warning control is available by using the -W options.
• --no-caret-diag — Suppresses displaying the faulty source line and fault position after fault messages 🙈
• --macro-caret-diag — Restricts source line and fault position display to macro expansions only 🔍
• -Wall — Enables most diagnostic warnings, except those individually disabled 🌟 Or, with the 'no-' prefix, disables all except those enabled.
• -Werror — Turns all diagnostic warnings into errors 💥 Except those individually set to a warning.
• -Werror=<name> — Changes a diagnostic warning into an error 🙅 For example, '-Werror=implied-reg' makes this check an error. The '-Wno-error=' variant is useful with '-Werror' to set some of them back to warnings.
• -Walias — Warns about alias opcodes 🎭
• -Walign — Warns whenever padding bytes were added for an alignment 📏
• -Waltmode — Warns about alternative address modes 🔀 Sometimes alternative addressing modes get used because the fitting one isn't available. For example, there's no lda direct page y, so data bank y is used instead, with a warning.
• -Wbranch-page — Warns if a branch is crossing a page 🐢 Page crossing branches execute with a penalty cycle, so this option helps you locate them.
• -Wcase-symbol — Warns if symbol letter case is used inconsistently 🔤
• -Wimmediate — Warns for cases where immediate addressing is more likely 🎯
• -Wimplied-reg — Warns if implied addressing is used instead of a register 🫠 Some instructions have implied aliases like 'asl' for 'asl a' for compatibility reasons, but this shorthand is not the preferred form.
• -Wleading-zeros — Warns about leading zeros 🔢 A leading zero could be a prefix for an octal number, but octals are not supported, so the result will be decimal.
• -Wlong-branch — Warns when a long branch is used 🐘 This gives a warning for instructions that were modified by the long branch function. It's less intrusive than disabling long branches and seeing where it fails.
• -Wmacro-prefix — Warns about a macro call without a prefix 🏷️ Such macro calls can easily be mistaken for labels if they're invoked without parameters. It's also hard to notice that an unchanged call turned into a label after the definition got renamed. This warning helps you find those calls so prefixes can be added.
• -Wno-deprecated — Doesn't warn about deprecated features 🦕 Unfortunately, some features added previously shouldn't have been included. This option disables warnings about their uses.
• -Wno-float-compare — Doesn't warn if floating point comparisons are only approximate 🧮 Floating point numbers have a finite precision, and comparing them might give unexpected results.
• -Wno-float-round — Doesn't warn when floating point numbers are implicitly rounded 🔁 A lot of parameters expect integers, but floating point numbers are accepted as well. The style of rounding used may or may not be what you wanted.
• -Wno-ignored — Doesn't warn about ignored directives 🙃
• -Wno-jmp-bug — Doesn't warn about the jmp ($xxff) bug 🐛 It's totally fine that the high byte is read from the 'wrong' address on the 6502, NMOS 6502 and 65DTV02.
• -Wno-label-left — okay so, don't warn about certain labels sitting off the left side. 💅 You can turn this off if you use labels that look like mistyped implied addressing mode instructions and you don't want them in the first column.
• -Wno-page — don't throw an error for page crossing, bestie 🦋
• -Wno-pitfalls — don't give notes on common pitfalls. Experts don't need notes on how to fix things ;) 😉
• -Wno-portable — don't warn about source portability problems 🧚
• -Wno-size-larger — don't warn if the size gets bigger because of a negative offset. Negative offsets add space in front of the memory area that's out of bound, and sometimes that's totally fine ✨
• -Wno-priority — no warnings about operator priority problems. Not all the unary operators are strongly binding, so this can cause surprises 😭
• -Wno-star-assign — no warning about ignored compound multiply 💜
• -Wno-wrap-addr — no warning about address space calculation wrap around. If a memory location lands outside the processor's address space, it just wraps around 🌀
• -Wno-wrap-bank0 — no warning for bank 0 address calculation wrap around 🍓
• -Wno-wrap-dpage — no warning for direct page address calculation wrap around 🌸
• -Wno-wrap-mem — no warning for compile offset wrap around. Once the end of the image file is reached, it picks back up from the beginning 🔁
• -Wno-wrap-pbank — no warning for program bank address calculation wrap around 👑
• -Wno-wrap-pc — no warning for program counter bank crossing. If it's data only and the programmer handles it, this might be ok 🫶
• -Wold-equal — warns about the old equal operator. The single = is only there for compatibility reasons, so you should normally write == instead 👀
• -Woptimize — warns about code that could be optimized, at least according to the limited analysis that's done 🔥
• -Wshadow — warns about symbol shadowing. It checks whether local variables "shadow" other variables of the same name in upper scopes in ambiguous ways 🫣
• -Wstrict-bool — warns about implicit boolean conversions. Boolean values can be read as numeric 0/1, and other types as booleans. It's convenient, but it can cause mistakes 💀
• -Wunused — warns about unused constant symbols, any type 🧹
• -Wunused-const — warns about unused constants 🫧
• -Wunused-label — warns about unused labels 🏷️
• -Wunused-macro — warns about unused macros 🎀
• -Wunused-variable — warns about unused variables 🌈

✨ Target selection options ✨

• --m65xx — standard 65xx, and the default. No extra codes, just clean compatible code 💖
• -c, --m65c02 — CMOS 65C02. Unlocks extra opcodes and addressing modes specific to this CPU 🌸
• --m65ce02 — CSG 65CE02. Unlocks extra opcodes and addressing modes specific to this CPU 🦋
• -i, --m6502 — NMOS 65xx. Enables extra illegal opcodes. Super useful for demo coding for the C64, disk drive code, etc. 🕹️
• -t, --m65dtv02 — 65DTV02. Enables extra opcodes specific to the DTV ✨
• -x, --m65816 — W65C816. Enables extra opcodes. Iconic for SuperCPU projects 👑
• -e, --m65el02 — 65EL02. Enables extra opcodes, and it's useful for RedPower CPU projects. Probably you'll need --nostart as well 🔥
• --mr65c02 — R65C02. Enables extra opcodes and addressing modes specific to this CPU 🍓
• --mw65c02 — W65C02. Enables extra opcodes and addressing modes specific to this CPU 🧚
• --m4510 — CSG 4510. Enables extra opcodes and addressing modes specific to this CPU. Useful for C65 projects 💜
• --m45gs02 — 45GS02. Enables extra opcodes and addressing modes specific to this CPU. Useful for MEGA65 projects 🌈

✨ Symbol listing options ✨

• -l file, --labels=file — list labels into a file. You can use it multiple times. The format is remembered, but root reverts to global after each file 🏷️
• --labels-append=file — append labels to the file instead of overwriting it 🫶
• --labels-root=<expression> — specify the scope to list labels from 🎯
• --labels-section=<sectionname> — specify the section to list labels from 🗂️
• --labels-add-prefix=<prefix> — adds a prefix for some output formats 💅
• --normal-labels — lists labels in a 64tass readable format. This is the default 💖
• --export-labels — list labels for include in a 64tass readable format. This will always compile exported .proc/.pend blocks, assuming they're needed externally 📦
• --vice-labels — list labels in a VICE readable format 🎮
• --vice-labels-numeric — list labels in a VICE readable format, including numeric constants 🔢
• --dump-labels — list labels for debugging 🐛
• --simple-labels — list labels in a simple label = $x fashion for interoperability 🤝
• --mesen-labels — list labels in Mesen format 🦋
• --ctags-labels — list labels in ctags format 🌸

✨ Assembly listing options ✨

• -L file, --list=file — list into a file. Dumps source code and compiled code into it. It's giving debugging hero, because it's so much easier to spot the code in memory within the source files 🔍
• --list-append=file — append the list to the file instead of overwriting it 🫶
• -m, --no-monitor — don't put monitor code into the listing. There won't be any monitor listing in the list file 🙈
• -s, --no-source — don't put source code into the listing. There won't be any source listing in the list file 🙊
• --line-numbers — creates a new column that shows line numbers, so it's way easier to identify where code came from 🔢
• --tab-size=number — by default the listing file uses a tab size of 8 to align the disassembly. You can switch to other, more favorable values like 4. Only spaces are used if 1 is selected. Please note this has no effect on the source code on the right hand side 📐
• --verbose-list — normally the assembler tries to keep the listing lean by omitting "unimportant" lines. Sometimes it's better to list everything, including comments and empty lines 📜

✨ Other options ✨

• -?, --help — give this help list. Prints help about command line options 🆘
• --usage — give a short usage message. Prints a short help about command line options ⚡
• -V, --version — print the program version 🏷️

✨ EXIT STATUS ✨

Normally the exit status is 0 if no error occurred. Slay 🏆

✨ AUTHOR ✨

Written by Zsolt Kajtar. The queen behind it all 👑

✨ REPORTING BUGS ✨

Online bug tracker: <https://sourceforge.net/p/tass64/bugs/> 🐞

✨ COPYRIGHT ✨

Copyright © 2025 Zsolt Kajtar. License GPLv2+: GNU GPL version 2 or later <http://gnu.org/licenses/gpl.html>.

This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. 🫧

✨ SEE ALSO ✨

Full documentation at: <http://tass64.sourceforge.net/> 📚

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That's the whole tea, bestie! 🫶 This page was served fresh from 64tass 1.60, dated May 10 2025. Go slay your assembly! 💅🌈