The main difference between bass and most other assemblers is, that it does not target to an single architecture or system. Thanks to its table driven approach it's possible (and yet necessary) to choose the target architecture.
It is possible (but not recommended) to switch back and forth between multiple architectures at any time.
Syntax:
architecture <name><name>- Switch to this target architecture by looking for the filearchitectures/<name>.arch. First it will look in~/bass/, then relative to the location of itself.
Note:
archis deprecated and might be removed soon.
Syntax:
base <offset>This command creates a signed displacement against the origin value, which is used when computing the pc (program counter) value for labels. This command allows mapping file address space into a virtual memory address space. It could be used for subsystems or bank switching.
Inserts binary data directly into the target file.
Syntax:
db ("<string>" | <variable> | <const>) [, ...]Sizes:
| command | size |
|---|---|
db |
1 Byte |
dw |
2 Byte |
dl |
3 Byte |
dd |
4 Byte |
dq |
8 Byte |
Note:
Like "integer" in other languages, the byte-length of these commands depends on the architecture. Besidesdb, all sizes may change as you switch between architectures.
Syntax:
delete "<filename>"This command deletes a file from disk. Useful for removing temporary work files needed by a project being assembled.
Syntax:
ds <offset>Seeks forward or backward from the current output file write address. The value can be positive (to seek forward) or negative (to seek backward.) This is useful for skipping bytes when in file modification mode.
Syntax:
endian <lsb | msb>This command controls whether multi-byte values (eg from dw and dd) are output in little-endian (lsb) or big-endian (msb) format. Default is lsb.
Note:
Most architectures (should) call this command when they get activated. This may lead to confusion, so keep it in mind.
Syntax:
copy <source_address>, <target_address>, <length>This command copies a block from the currently open file to another location within the file. It does this by reading the entire block in first, and then writing said block out, so be careful with overlapping addresses.
Syntax:
fill <length> [, <with>]Inserts number of bytes into the target file. The default fill byte is 0x00, but can be specified via .
Syntax:
include "<filename>"Includes another source file in place of this command.
Note:
This command is parsed in the very first phase, and is only noted here for completeness. At the time whenincludeis applied, no other commands have been processed, so do not attempt conditional recursion on the same source file or you'll get an infinite loop which will eventually exhaust all memory.
Syntax:
insert [<name>, ] "<filename>" [, <offset>] [, <length>]This command inserts a binary file into the target file. You can optionally specify a name, offset and length. If you specify a name, it will create a label by the given name, which contains the address where the data begins, and it will also create name.size, which contains the size of the included data. If you specify an offset, it will seek that far into the referenced filename before copying the data. If you want to specify a length, you must specify an offset first, and the length will determine the maximum number of bytes to copy from the referenced filename.
Syntax:
map <char> [, <value>] [, <length>]Modifies the mappings for strings passed to db, dw, etc. This can be used to map strings to custom tilemaps that do not follow traditional ASCII values.
<char> is the first value to modify, <value> is the value to map said char to, and <length> can be used for contiguous entries.
For instance, if A-Z appear sequentially, give a value of 26 for the length, to avoid having to declare 26 separate assignments.
map 'a', 0x01, 26Each step of <length> increments both the char and value by exactly one, so the characters must be contiguous with both ASCII and your custom map for this to work.
If you wish to restore the table to its default ASCII values, use the following command:
map 0, 0, 256Syntax:
origin <offset>This command seeks the output file write cursor to the specified location.
Syntax:
output "<filename>" [, <create>]This command can be used in place of the -o filename [-create] command-line argument, or in addition to it, and can open multiple files sequentially for output (only one output file can be open at a time.) The <create> parameter, if specified, states to overwrite the target file if it already exists. Otherwise, the file is opened in modification mode.
Prints information to the terminal. Useful for debugging. Using error aborts assembly, all other functions will not.
print is the Swiss Army knife of all commands. It allows you to print multiple parameters to the screen. Strings, Characters, Numbers, Variables, Constants and Defines all work.
Syntax:
print <something> [, <something>]The print directive also supports formatting prefixes for variable or constant expressions. These are: binary, hex, and char.
Example:
print "%", binary:15 //prints %1111
print "$", hex:65536 //prints $10000
print "'", char:65, "'" //prints 'A'Note:
Defined parameters will be evaluated as single parameter, but will be pasted verbatim inside of a string.
Example:// v15-18 constant a = 2 define x = 1 + a print {x}, ", {x}\n" // prints "3, 1 + a\n"This may lead to wrong assumptions about the strings content if you debug using print commands.
The queue feature works like a small stack for certain system states <state> such as origin, base and pc. It works in a 'last in first out' manner.
Note:
Right now all values share one queue! In other words you should be very careful about the order if you 'store' and 'reload' many values at once.
We consider this as dangerous. The feature will redesigned in the near future.
Syntax:
dequeue <state>, ...Restores the given state(s) from the queue.
Syntax:
enqueue <state>, ...Puts the given state(s) into the queue.