A rewriting of Core.exe for Event Assembler.

Event Assembler Language is a language for describing the writing of binary or formatted payloads with relative addressing. A script is a series of statements; each statement is either a directive, a command, a label, or a raw.

If no offset changing commands are given, then the assembler continues writing data sequentially to the current offset.

A few of the common directives are #include, #define, #ifdef (and #ifndef, #else, #endif), #incbin, #incext, and #incextevent.

#include and #ifdef function as they would in C. #include inserts the contents of another file at that location. #ifdef is for conditional parsing.

We may #define definitions or macros. Definitions are substituted as-is on a token level. They may only refer to previous definitions (as parsing is one-pass). Macros are akin to definitions, but take several parameters. Substitution is done at the token level. This is akin to how C does it.

#incbin writes the binary contents of the file provided at the current offset.

#incext calls the provided tool (in the ./Tools folder) with the given parameters along with --to-stdout. It then writes the binary output from stdout to the current location.

#incextevent calls the provided tool with the given parameters along with --to-stdout, then treats the output from stdout as an event file, and effectively #includes it.

These commands affect the current location: ORG, ALIGN, PUSH, POP. ORG changes the current offset to the one given, ALIGN changes the current offset to the next multiple of the one given. PUSH stores the current offset for future use of POP, which returns the current offset to what was PUSHed.

These commands report assembler state to the appropriate category: MESSAGE, WARNING, ERROR. Any number of expressions can be given for evaluation, or a string may be provided (in quotes).

These commands ensure a certain state for the assembler: PROTECT, ASSERT. PROTECT start end will error on any future write to anywhere in the range of offsets provided, and provide where the write occurred for debugging. PROTECT offset only protects the single offset. ASSERT will error if the provided expression is negative.

Raws are defined in a separate language, and specification for all raws are (by default) in the ./Language Raws folder. Raws describe a pattern of binary data to be written, say for example, "the short 0x1234 followed by two one-byte coordinates". Raws may also be written with no assumption about the data (e.g. "a byte").

Having LabelName: brings in LabelName as an identifier which evaluates to what the current offset was when the label was defined.

currentOffset (case insensitive) always gets evaluated to the current offset of the assembler.

Assuming the raw WORD assembles the word(s) provided after it, the following script writes 0xDEADBEEF at 0x1000, and writes 0x08001000 at 0x2000

ORG 0x1000
MyLabel:
WORD 0xDEADBEEF

#define Pointer(Location) "WORD (Location | 0x08000000)"

ORG 0x2000
Pointer(MyLabel)

Snek-GBA, by Leonarth. A full, independently made GBA game. ColorzCore was used as the linker and build tool.

VBA: Blitz Tendency, by Crazycolorz5. An extensive, community mod of Fire Emblem: The Sacred Stones. Considering the large number of contributors, ColorzCore was used to make sequences of binary writes version controllable. It was also used as the build tool.

Output assembly source file and linker script for building with gcc tool chain rather than write to ROM directly.