net: SYS_POLLCON + larger console ring for link-injected input

Programs that own their main loop (the IRC client) need to poll for
typed input without blocking. pollin() only sees the on-screen keyboard;
bytes injected over the link (gbhub 'type', for scripted/hub-driven
sessions) land in the kernel console ring, previously only drained by the
blocking KGetc path. Add SYS_POLLCON: a non-blocking con_pop for
userland.

Also enlarge that console ring 16 -> 64. One net_pump drains an entire
serial burst into the ring at once, so a whole injected command line has
to fit or bytes are dropped and lines merge (a 20-char command came out
truncated and glued to the next). 64 covers a full line; mask stays a
power of two.

1 files changed, 10 insertions, 0 deletions

diff --git a/src/net.asm b/src/net.asm
index f2c4279..8309242 100644
--- a/src/net.asm
+++ b/src/net.asm
@@ -54,6 +54,16 @@ sys_srecv_nb::
     and a                       ; CF = 0 (got a byte)
     ret
 
+; sys_pollcon() -> A = a queued console-ring byte (link-injected input,
+; e.g. gbhub 'type'), or 0 if none. Non-blocking twin of KGetc's con_pop
+; path: programs that own their main loop (irc) poll this alongside the OSK.
+; The ring fills during net pumps, which such programs do constantly.
+sys_pollcon::
+    call con_pop
+    ret nc                      ; got a byte
+    xor a
+    ret
+
 ; sys_pollin() -> A = char typed on the OSK this poll, or 0 if none.
 sys_pollin::
     call pad_poll