Drives the unmodified httpd.c and uip.c through a handshake and a GET
from a client that moves its receive window, and compares the bytes that
reach the wire with the file they are meant to carry. The served file
holds a position-dependent pattern, so a repeat or a gap is reported at
its offset rather than as content that differs somewhere.
The first scenario holds the window still and must pass: it is the check
that the bench itself is sound, before the two moving-window scenarios
are believed.
The switch is reached through four register functions and the SFR_DATA
registers, so a flat register file behind them is enough to run the table
code on the host. A few addresses are live: writing TBL_CTRL with EXECUTE
performs the VLAN or L2 operation at once and clears the bit, STAT_GET
fetches a counter, L2_TBL_FLUSH_CTRL drops entries. Nothing ever reports
busy, so a polling loop runs once and the tests say nothing about what
happens when hardware stalls; that question was settled elsewhere.
The header states the VLAN and L2 entry layouts on its own, so a test can
hold what rtl837x_port.c writes against a second reading of the same bits
rather than against itself. The first suite does that for the VLAN entry,
the PVID register two ports share, the static multicast and management
entries, the per-port flush and the trunk registers. Two stub headers stand
in for the ones a firmware build generates, so the harness needs no SDCC
build first.