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.

6 files changed, 30 insertions, 5 deletions

diff --git a/c/gbos.h b/c/gbos.h
index 390fe3a..2350665 100644
--- a/c/gbos.h
+++ b/c/gbos.h
@@ -17,6 +17,8 @@ void          ssend(unsigned char b);   /* link-port: transmit one byte */
 unsigned char srecv(void);              /* link-port: receive one byte (blocks) */
 int           srecv_nb(void);           /* link-port: receive, or -1 if none */
 unsigned char pollin(void);             /* poll OSK for a typed char, or 0 */
+unsigned char pollcon(void);            /* poll console ring (link-injected
+                                           input, filled by net pumps), or 0 */
 unsigned char sys_net(void *req);       /* socket layer trap (see sock.h)  */
 void          gsleep(unsigned char units); /* delay units*(1/64)s (raw trap)  */
 void          msleep(unsigned int ms);     /* delay ~ms milliseconds          */
diff --git a/c/libc.s b/c/libc.s
index b413f3b..5b176d9 100644
--- a/c/libc.s
+++ b/c/libc.s
@@ -1,6 +1,6 @@
 	.module libc
 	.globl _writes, _putc, _puts, _nl, _strlen, _readc, _sexit, _getpid, _getargs
-	.globl _open, _close, _fgetc, _fputc, _flist, _fremove, _pipe, _ssend, _srecv, _srecv_nb, _pollin
+	.globl _open, _close, _fgetc, _fputc, _flist, _fremove, _pipe, _ssend, _srecv, _srecv_nb, _pollin, _pollcon
 	.globl _sys_net, _gsleep
 	;; SDCC sm83 sdcccall(1): 1st arg -> A (byte) or DE (pointer); ret A / BC.
 	;; rst $30 (the trap) clobbers BC/DE/HL; SDCC treats them caller-saved, so
@@ -136,6 +136,12 @@ _pollin:
 	rst	#0x30
 	ret
 
+	;; unsigned char pollcon(void) -> A  (queued console byte, or 0)
+_pollcon:
+	ld	c, #35			; SYS_POLLCON
+	rst	#0x30
+	ret
+
 	;; unsigned char open(const char *name /*DE*/, unsigned char mode /*A*/) -> A(fd)
 _open:
 	ld	b, a			; B = mode
diff --git a/include/gbos.inc b/include/gbos.inc
index e9f8d7d..55f0681 100644
--- a/include/gbos.inc
+++ b/include/gbos.inc
@@ -133,7 +133,8 @@ DEF SYS_SRECVNB EQU 31   ; link-port: receive, non-blocking (-> A=byte, CF=none)
 DEF SYS_POLLIN  EQU 32   ; poll OSK for a typed char       (-> A=char or 0)
 DEF SYS_NET     EQU 33   ; socket layer                    (DE=&netreq -> A=result)
 DEF SYS_SLEEP   EQU 34   ; cooperative delay               (B = 1/64-second units)
-DEF SYS_MAX     EQU 35
+DEF SYS_POLLCON EQU 35   ; poll console ring (link-injected -> A=byte or 0)
+DEF SYS_MAX     EQU 36
 
 ; ---- socket layer (SYS_NET) --------------------------------------------------
 ; netreq struct (in caller RAM; DE points to it):
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
diff --git a/src/socket.asm b/src/socket.asm
index 0720b0a..51179b4 100644
--- a/src/socket.asm
+++ b/src/socket.asm
@@ -64,7 +64,12 @@ wNetRxBuf::    DS 320      ; rx frame assembly / parse
 wNetRxLen::    DS 2        ; 16-bit: frames can exceed 255 bytes (DHCP/BOOTP)
 wNetRxEsc::    DS 1
 wNetInFrame:: DS 1        ; net_pump: currently inside a SLIP frame?
-wConRing::    DS 16       ; console-input ring: non-framed bytes from the link
+wConRing::    DS 64       ; console-input ring: non-framed bytes from the link
+                          ; (link-injected console input, e.g. gbhub 'type').
+                          ; One net_pump drains a whole serial burst into here
+                          ; at once, so it must hold a full injected command
+                          ; line - 16 was too small (dropped bytes, merged
+                          ; lines). Size MUST stay a power of two (mask below).
 wConHead::    DS 1
 wConTail::    DS 1
 wNetUdpPort::  DS 2      ; scratch: UDP dst port being demuxed
@@ -112,7 +117,7 @@ con_push::
     ld b, a
     ld a, [wConTail]
     inc a
-    and 15
+    and 63
     ld c, a
     ld a, [wConHead]
     cp c
@@ -145,7 +150,7 @@ con_pop::
     ld c, [hl]
     ld a, b
     inc a
-    and 15
+    and 63
     ld [wConHead], a
     ld a, c
     and a                       ; CF = 0
diff --git a/src/syscall.asm b/src/syscall.asm
index 2adf5bf..bd58cc2 100644
--- a/src/syscall.asm
+++ b/src/syscall.asm
@@ -69,6 +69,7 @@ SyscallTable:
     dw sys_pollin               ; 32 POLLIN
     dw sys_net                  ; 33 NET
     dw sys_sleep                ; 34 SLEEP
+    dw sys_pollcon              ; 35 POLLCON
 
 ; -----------------------------------------------------------------------------
 sys_nosys: