Memory Layout

Endianness

WebAssembly is, in general, a little-endian system.

Memory Map

WASM-4 uses a fixed memory layout of 64 KB.

Address	Size (Bytes)	Description
$0000	4	Unused
$0004	16	PALETTE
$0014	2	DRAW_COLORS
$0016	4	GAMEPADS
$001a	2	MOUSE_X
$001c	2	MOUSE_Y
$001e	1	MOUSE_BUTTONS
$001f	1	SYSTEM_FLAGS
$0020	1	NETPLAY
$0021	127	Reserved for future use
$00a0	6400	FRAMEBUFFER
$19a0	58976	Available program memory

PALETTE

An array of 4 colors, each represented by a 32 bit integer. Each color is laid out in memory like this:

Bits	Description
0 - 7	Blue channel
8 - 15	Green channel
16 - 23	Red channel
24 - 31	Unused

Example:

PALETTE[0] = 0xff0000; // Set the first palette color to red,PALETTE[1] = 0x00ff00; // the second to green,PALETTE[2] = 0x0000ff; // the third to blue,PALETTE[3] = 0xffffff; // and the fourth to white.

DRAW_COLORS

Indexes into the color palette used by all drawing functions.

Bits	Description
0 - 3	Draw color 1
4 - 7	Draw color 2
8 - 11	Draw color 3
12 - 15	Draw color 4

Each draw color can be a value between 1 and 4 representing a palette color, or 0 to signify transparency.

Example:

// Set the first draw color to palette color #2, the second to// transparent, and the third to palette color #4.*DRAW_COLORS = 0x402;

GAMEPADS

4 gamepads, with each gamepad represented by a single byte.

Bit	Name	Description
0	BUTTON_1	X button
1	BUTTON_2	Z button
2		Unused
3		Unused
4	BUTTON_LEFT	D-pad left
5	BUTTON_RIGHT	D-pad right
6	BUTTON_UP	D-pad up
7	BUTTON_DOWN	D-pad down

MOUSE_X

Signed 16 bit integer containing the X position of the mouse. Can contain positions outside of the game window.

MOUSE_Y

Signed 16 bit integer containing the Y position of the mouse. Can contain positions outside of the game window.

MOUSE_BUTTONS

Byte containing the mouse buttons state.

Bit	Name	Description
0	MOUSE_LEFT	Left mouse button
1	MOUSE_RIGHT	Right mouse button
2	MOUSE_MIDDLE	Middle mouse button

SYSTEM_FLAGS

Byte containing flags that modify WASM-4's operation. By default all flags are off.

Bit	Name	Description
0	SYSTEM_PRESERVE_FRAMEBUFFER	Prevent clearing the framebuffer between frames.
1	SYSTEM_HIDE_GAMEPAD_OVERLAY	Hide the gamepad UI overlay on mobile.

NETPLAY

Byte containing netplay multiplayer state.

Bits	Description
0 - 1	Local player index (0 to 3).
2	Set if netplay is currently active.

FRAMEBUFFER

Array of 160x160 pixels, with each pixel packed into 2 bits (colors 0 to 3).

This region can be freely modified for direct pixel manipulation.