Another World draw_sprite_shape customasm rule

; Draw Shape Opcode:
;
;   Bits 7 & 6 - 00: Unknown
;                01: Draw sprite shape
;                1X: Draw background shape
;
;   When drawing a background shape:
;   Bits 6 - 0 - High 7 bits of the shape address
;
;   When drawing a sprite shape:
;   Bits 5 & 4 - 00: X coordinate is 16-bits immediate (BE)
;                01: Read X coordinate from memory indicated by 8-bit immediate
;                10: X coordinate is 8-bit immediate
;                11: X coordinate is 8-bit immediate + 256
;
;   Bits 3 & 2 - 00: Y coordinate is 16-bits immediate (BE)
;                01: Read Y coordinate from memory indicated by 8-bit immediate
;                10: Y coordinate is 8-bit immediate
;                11: Unknown
;
;   Bits 1 & 0 - 00: Zoom is 64
;                01: Read Zoom from memory indicated by 8-bit immediate
;                10: Zoom is 8-bit immediate
;                11: Shape to draw is from shared shapes. Zoom is 64
;
;   Operand bytes:
;       - u16 (offset >> 1)
;       - u8 or u16 (x)
;       - u8 or u16 (y)
;       - u8 zoom (optional)
;
;   Instruction Format:
;       draw_sprite_shape from_shared (0 | 1), offset (u16), x (u8 | [u8] | u16 | u16 < 512), y (u8 | [u8] | u16), zoom (u8 | [u8] | 64)
;
;   Examples:
;       draw_sprite_shape 1, 0x0cba, [0x01], [0x02], 64
;       draw_sprite_shape 0, 0xde5c, 0x104, [0x34], [0x04]


draw_sprite_shape {from_shared}, {offset: u16}, [{x: u8}], [{y: u8}], {z: u8} => {
    assert(from_shared == 0)
    assert(z == 64)
    0b01 @ 0b01 @ 0b01 @ 0b00 @ (offset >> 1)`16 @ x`8 @ y`8
}
draw_sprite_shape {from_shared}, {offset: u16}, [{x: u8}], [{y: u8}], [{z: u8}] => {
    assert(from_shared == 0)
    0b01 @ 0b01 @ 0b01 @ 0b01 @ (offset >> 1)`16 @ x`8 @ y`8 @ z`8
}
draw_sprite_shape {from_shared}, {offset: u16}, [{x: u8}], [{y: u8}], {z: u8} => {
    assert(from_shared == 1)
    assert(z == 64)
    0b01 @ 0b01 @ 0b01 @ 0b11 @ (offset >> 1)`16 @ x`8 @ y`8
}
draw_sprite_shape {from_shared}, {offset: u16}, [{x: u8}], {y: u8}, {z: u8} => {
    assert(from_shared == 0)
    assert(z == 64)
    0b01 @ 0b01 @ 0b10 @ 0b00 @ (offset >> 1)`16 @ x`8 @ y`8
}
draw_sprite_shape {from_shared}, {offset: u16}, [{x: u8}], {y: u8}, [{z: u8}] => {
    assert(from_shared == 0)
    0b01 @ 0b01 @ 0b10 @ 0b01 @ (offset >> 1)`16 @ x`8 @ y`8 @ z`8
}

etc....