It is a convenience directive for defining least significant byte first two byte words, as the Z80 uses them. Multiple expressions, separated by commas, may be. ZASM is a compiler/assembler and monitor (including disassembler and debugger) for the Z80 CPU. It runs under Linux (probably also. Uses. The easiest way to put data directly into your program. Note that since the z80 processor is little-endian, loading into a bit register from.

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Awsembleur allows definition of one or more literal bytes, as well as strings of bytes. All definitions should be separated by commas.

Strings of bytes should be between double quotes.

Z80 Assembler Syntax

It is a convenience directive for defining least significant byte first two byte words, as the Z80 uses them.

Multiple expressions, separated by commas, may be specified. It takes one or two arguments, num and val. It reserves num bytes of space and initializes them to val. If val is omitted, it defaults to 0.

At the end of the program, it is allowed to use the “end” directive. There is no need to do this. Everything after this directive is ignored.


Assembler directives

This can be used to put some comments at the end. This sets the assembler’s idea of the current address. It takes aswembleur argument, which must evaluate to a value in the first pass it may not use labels which are defined later.

At the start, the current address is set to 0. Normally, the first directive in a program is org, to set the starting address. Using this directive more than once can be useful to create code which is to be executed at the same address, for example when the memory is mapped. At the start of each page, the code can set the starting address assembleyr the mapping address. The previously defined pages are not overwritten.

Note that no code is generated by this directive, so if padding bytes are required, they must be assembleu using defs. Org only changes the assembler’s idea of “where” it is. In the following example, the output contains 4 bytes: People have requested to be able to overwrite the assembleeur output. This is what seek is for. It will seek in the output file and start overwriting previous output.

This is mostly useful in combination with incbin. It allows the included binary to be “patched”.

If the argument of seek is greater than the current output size, the file is extended with zeros. As in C but without thethis includes an other source file.


Almost any name is possible without escape characters, because of the quote rules. The first non-whitespace character after the include directive is considered the starting quote.

The filename is then read, until the assdmbleur quote, which is the same as the starting quote. Incbin stands for “include binary”. It allows any binary data to be included verbatim into the output.

The argument is given in the same way as for include. Parts of the code can aasembleur omitted using these conditional statements. Code which is not assembled is checked for a correct command. Otherwise it is not touched, which means that if you use these directives, a successfull assembler execution does not imply that all the code is correct. With these directives it is possible to define new commands, which will output defined code.

After this definition, it is possible to use the macro, like this: