Ruling R14: the frame CRC now covers header bytes 0..11 only. A
payload-wide CRC cost the terminal ~139 instructions per payload byte
(the parser, not the wire or the blitter, was the frame-rate ceiling),
while every datagram already carries an Ethernet FCS the LANCE checks
and the length bound catches truncation. frame.py, fp_parse and the
harness's own frame signer follow the new rule; a corrupted payload
byte is now ACCEPTED and a corrupted header byte rejected, stated
explicitly in both test suites, and the C golden vectors were
regenerated from frame.py.
Measured after: RX_READY_A write -> first RX_OK read is 1 emulated
frame for a 20,480-byte frame (84 before), which is the frame hook's
resolution.
Ruling R15: draw mode deletes its dump files before the run (wrapper
and Lua) so a failed run cannot be judged on the previous screen; a
wait that hits its cap reports "timed out waiting for the frame" and
the checker reports it as a timeout, not as pixel mismatches; the
checker asserts the VRAM canary word is 0xA5C3, so a payload that
stopped arming it fails instead of passing quietly.
rx mode now corrupts a header byte in slot B, because a payload flip is
accepted by design under R14.
One PIXBLT B,XY per source row paints the whole screen: DYDX names
`stretch` rows and SPTCH = 0 makes each of them read the same packed
source row, so the vertical stretch costs no extra CPU work.
vram_b.asm carries the primitive (PSIZE=1, CONVSP/CONVDP=0x14,
PMASK=0, OFFSET=0x04000000, DPTCH=0x800, raster op 0) plus DINT/EINT
thunks; vidstream.c masks interrupts for the burst (spec 8.9), refuses
geometry the screen cannot hold, and counts an OS repaint through a
sentinel word in the unused right edge of the last screen row
(OS_TOUCH, 0x01810220).
MAME mode draw injects a 128-row frame (stretch 8 = 1024 screen rows,
ruling R3) and dumps the screen; vidstream_check.py compares all 1024
rows against the bytes actually delivered. RED: 0/1024 rows matched.
GREEN: 1024/1024, RX_OK=1, OS_TOUCH=0.
Fixes a latent harness bug found on the way: `bpclear <address>` takes
a breakpoint INDEX, so the idle-loop breakpoint was never cleared; once
a burst masked interrupts long enough, its stale action fired again and
re-entered main (a second malloc, counters back to 0).
opencode.energia.arti.ee