regression from v6 to v7 (current micro:bit release)

[tballmsft]

The release last year regressed the tool pxt-jacdac/tools/microbit-jukebox. In v6 it works fine; in v7 we get error 022 (alloc too large). Repro steps.

1. clone https://github.com/microsoft/pxt-jacdac
2. cd to pxt-jacdac/tools/microbit-jukebox
3. mkc init
4. mkc -d // deploy to attached microbit (v2)
5. see 022 error code
6. edit mkc.json and change targetWebSite to https://makecode.microbit.org/v6
7. repeat mkc -d and see happy micro:bit (smiley face, no error code

[tballmsft]

error is raised in gc.cpp

void *gcAllocate(int numbytes) {
    size_t numwords = BYTES_TO_WORDS(ALIGN_TO_WORD(numbytes));
    // VVLOG("alloc %d bytes %d words", numbytes, numwords);

    if (numbytes > GC_MAX_ALLOC_SIZE)
        soft_panic(PANIC_GC_TOO_BIG_ALLOCATION);

[tballmsft]

On Jan 2024, bumped UP alloc for v2: 403c417 .

So

• v6 has GC_MAX_ALLOC_SIZE = 9000 for both microbit v1 and v2

Whereas

• v7 has GC_MAX_ALLOC_SIZE = 9000 for mbit v1 and GC_MAX_ALLOC_SIZE = 11000 for mbit v2

[tballmsft]

in the end, this is a code overflow due to use of "settings" by pxt-jacdac, which explains the difference in v6 and v7 (which fixed settings location due to conflict)