The data statement enables data to be included with code. Unfortunately it doesn't seem possible to access it without explicitly manipulating the program counter. Attempts to assign labels to registers produce an error. For example it would be good to be able to write something like this (to access an element from a data array):

d1 = const(12)
d2 = const(13)

@micropython.asm_thumb
def bar(r0):
    b(START)

    label(MYDATA)
    data(4, d1, d2)

    label(START)
    movwt(r1, MYDATA)
    add(r0, r0, r0) # Convert index to byte offset
    add(r0, r0, r0)
    add(r1, r1, r0) # add offset to data address
    ldr(r0, [r1, 0])

But this fails with "unsupported Thumb instruction 'movwt' with 2 arguments". The code can be made to work as follows, but it seems inelegant compared to using a label.

d0 = const(1234567)
d1 = const(987654)
d2 = const(3*d1)

@micropython.asm_thumb
def getdata(r0):
    push({pc})
    b(START)
    data(4, d0, d1, d2)
    label(START)
    pop({r2})
    add(r2, 2)          # skip the b() instruction
    add(r0, r0, r0)
    add(r0, r0, r0)     # Convert array offset to bytes
    add(r2, r2, r0)     # Add to adjusted address
    ldr(r0, [r2, 0])    # get the requested data