uci-m3 stage 2: READ 1472 B over a Data More continuation (measured: no gain; draft)

CLAUDE.md

@@ -119,7 +119,9 @@ Variables:
     `$(error)`s, not in `PACKAGE_VARIANTS`. `HTTPS_PIN_SPKI_SHA256` = trust
     PIN, `M3_ALLOW_TLS12=1` offers hardened 1.2. UCI reads are unfenced
     (writes keep `uci_fence`); `M3_READ_FENCE=1` restores the old client
-    byte for byte, `M3_TRACE=1` = per-READ timing records (measurement only;
+    byte for byte; READs ask 1472 B over one Data More continuation,
+    `M3_READ_ONE_BLOCK=1` = 893 B one-block READs (the previous default);
+    `M3_TRACE=1` = per-READ timing records (measurement only;
     `rig_https_m3.py timed`). Model + mutants:
     `tools/check_m3_client.py`, `tools/mutate_m3_client.py` (standalone,
     need an m3 build); hardware: `rig_https_banner.py`, `rig_https_m3.py`.

Makefile

@@ -50,10 +50,12 @@ $(error M3_ALLOW_TLS12 must be 1 (offer TLS 1.3 and hardened 1.2) or 0/unset (TL
 endif
 # M3_READ_FENCE=1: a uci_fence after every UCI register READ too, as before
 # (src/net/uci-m3/m3.inc, "Read pacing"): the A/B arm and the fallback.
+# M3_READ_ONE_BLOCK=1: READs of one block (893 B), no Data More continuation
+# (m3.inc, "READ size"): the stage-1 client, an A/B arm.
 # M3_TRACE=1: per-net_poll timing records, a measurement build only.
-$(foreach k,M3_READ_FENCE M3_TRACE,$(if $(filter-out 0 1,$($(k))),$(error $(k) must be 1 or 0/unset)))
+$(foreach k,M3_READ_FENCE M3_READ_ONE_BLOCK M3_TRACE,$(if $(filter-out 0 1,$($(k))),$(error $(k) must be 1 or 0/unset)))
 else
-$(foreach k,M3_READ_FENCE M3_TRACE,$(if $(filter-out 0,$($(k))),$(error $(k)=$($(k)) applies only to BACKEND=uci-m3)))
+$(foreach k,M3_READ_FENCE M3_READ_ONE_BLOCK M3_TRACE,$(if $(filter-out 0,$($(k))),$(error $(k)=$($(k)) applies only to BACKEND=uci-m3)))
 endif
 
 # X25519 is always the libs/x25519 sibling (issue #245 retired the in-tree
@@ -125,6 +127,9 @@ endif
 ifeq ($(M3_READ_FENCE),1)
 CA65FLAGS += -D M3_READ_FENCE=1
 endif
+ifeq ($(M3_READ_ONE_BLOCK),1)
+CA65FLAGS += -D M3_READ_ONE_BLOCK=1
+endif
 ifeq ($(M3_TRACE),1)
 CA65FLAGS += -D M3_TRACE=1
 endif

src/net/uci-m3/m3.inc

@@ -35,6 +35,8 @@ M3_FLAG_TLS13_ONLY  = $01       ; REQUIRE_TLS13; bits 1-7 must be 0 (82)
 M3_HOST_MAX         = 253       ; host 1..253 bytes, no $00 (S 1.1 tail grammar)
 M3_WRITE_MAX        = 892       ; WRITE_SOCKET plaintext per command
 M3_READ_MAX         = 893       ; one response block: 2-byte header + 893
+M3_READ_MORE        = 895       ; a continuation block: payload only
+M3_READ_TOTAL       = 1472      ; one READ, over Data More (S:2012-2013)
 M3_STATUS_MAX       = 40        ; every M3 status line is <= 40 B (ER-8)
 M3_SWEEP_HANDLES    = 16        ; this firmware's handle range 0..15 (ER-9)
 
@@ -81,6 +83,22 @@ M3_B_HTTP_IDLE      = 6000      ; http_recv_body: 60 s with no byte arrived
 ;   +8  bytes put into the ring (16-bit)
 ;   +10 m3_poll_result
 ;   +11 $DF1C read right after that READ's PUSH and its fence
+; --- READ size (M3_READ_ONE_BLOCK) ----------------------------------------
+; A READ asks for up to M3_READ_TOTAL: the first block holds the header and
+; 893 bytes, the rest comes in ONE continuation block over Data More, which
+; the client data-accepts after reading the first block to its end (S:2013,
+; errata ER-1 N-1 and ER-5; firmware network_target.cc start_read_reply /
+; get_more_data). A continuation is taken only after a FULL block and only
+; while the header still owes bytes; anything else stays a hole (ER-5).
+; `M3_READ_ONE_BLOCK=1` (and M3_READ_FENCE=1, the pre-change client) asks
+; for at most one block and takes every Data More as a hole, as before.
+.if .defined(M3_READ_FENCE) .or .defined(M3_READ_ONE_BLOCK)
+M3_READ_REQ         = M3_READ_MAX
+.else
+M3_READ_REQ         = M3_READ_TOTAL
+M3_MULTI_BLOCK      = 1
+.endif
+
 M3_TR_BASE          = $6000
 M3_TR_REC           = 12
 M3_TR_CAP           = ($A000 - M3_TR_BASE) / M3_TR_REC

src/net/uci-m3/m3_cmd.s

@@ -54,6 +54,9 @@
 .export m3_code
 .export m3_wedged
 .export m3_dl
+.ifdef M3_MULTI_BLOCK
+.export m3_next_block
+.endif
 .ifdef M3_TRACE
 .export m3_tr_sample
 .export m3_tr_delta
@@ -465,6 +468,35 @@ m3_accept:
         sta UCI_CONTROL
         jmp m3_settle
 
+.ifdef M3_MULTI_BLOCK
+; =============================================================================
+; m3_next_block — data-accept a Data More block (read to its end) and wait for
+; the next one, up to 12 s from the accept (errata ER-1, N-1: the Nios serves
+; it from its buffer). The accept drops the interface to state "01" until
+; the next block is validated (command_protocol.vhd).
+; Out: C=0 the next block is staged. C=1 ABORTed at the bound (net_last_error
+;      $89, m3_wedged if bit 2 never cleared): its bytes are lost.
+; Clobbers: A, X, Y
+; =============================================================================
+m3_next_block:
+        jsr m3_accept
+        lda #<M3_B_TLS
+        ldx #>M3_B_TLS
+        ldy #M3_DL_CMD
+        jsr m3_dl_arm               ; the accept + 12 s
+        lda #UCI_STAT_REPLY_VALID
+        jsr m3_wait_set
+        bcs :+
+        rts                         ; C=0
+:       lda #UCI_ERR_WAIT_TIMEOUT
+        sta net_last_error
+        lda #<M3_B_POST_ABORT
+        ldx #>M3_B_POST_ABORT
+        jsr m3_abort_wait
+        sec
+        rts
+.endif
+
 ; m3_finish — drop the rest of the block, read the status line, accept.
 ; The status is read BEFORE the accept, which empties both queues.
 m3_finish:

src/net/uci-m3/net.s

@@ -82,6 +82,9 @@
 .import m3_status_seen
 .import m3_code
 .import m3_wedged
+.ifdef M3_MULTI_BLOCK
+.import m3_next_block
+.endif
 .ifdef M3_TRACE
 .import m3_tr_sample
 .import m3_tr_delta
@@ -708,14 +711,19 @@ m3_status_number:
 ; =============================================================================
 ; net_poll — one READ into the rx ring.
 ;
-; Request min(ring free - 1, 893): one response block, no Data More (S 1.5).
+; Request min(ring free - 1, M3_READ_REQ): 1472 over a first block and one
+; Data More continuation, or 893 and one block under M3_READ_ONE_BLOCK /
+; M3_READ_FENCE (m3.inc, "READ size"; S 1.5, S:2013).
 ; Then, by header and status (S 1.6, Appendix A, ER-5/7/12):
 ;   no header (bit 7 clear)  an empty reply (81/82): a READ of ours that
 ;                            the firmware refused. ERROR, still owned.
 ;   n > 0                    data into the ring. A block that is not read
-;                            to its end (short, over-long, Data More)
-;                            leaves a hole in the stream: ERROR, owned,
-;                            so the CLOSE that follows is sent (ER-5).
+;                            to its end, a short one, an over-long one, or
+;                            a Data More the header does not owe, leaves a
+;                            hole in the stream: ERROR, owned, so the CLOSE
+;                            that follows is sent (ER-5). A continuation
+;                            that does not come within 12 s of its accept
+;                            is ABORTed: $89, ERROR, owned.
 ;   $FFFF + 02,..: 11        nothing yet (M3_POLL_IDLE).
 ;   $FFFF + anything else    the number is not ours ("02,NO DATA: 9", ER-7):
 ;                            stop, and do NOT CLOSE it. ERROR, not owned.
@@ -773,13 +781,13 @@ net_poll:
         rts
 :
         lda m3_req
-        cmp #<M3_READ_MAX
+        cmp #<M3_READ_REQ
         lda m3_req+1
-        sbc #>M3_READ_MAX           ; C=1 iff req >= MAX
+        sbc #>M3_READ_REQ           ; C=1 iff req >= MAX
         bcc :+
-        lda #<M3_READ_MAX
+        lda #<M3_READ_REQ
         sta m3_req
-        lda #>M3_READ_MAX
+        lda #>M3_READ_REQ
         sta m3_req+1
 :
         lda #M3_POLL_END
@@ -908,6 +916,16 @@ net_poll:
         lda tcp_recv_tail+1
         adc #>tcp_recv_buf
         sta @p_store+2
+.ifdef M3_MULTI_BLOCK
+        lda tcp_recv_tail+0         ; where this READ's bytes start
+        sta m3_cp0
+        lda tcp_recv_tail+1
+        sta m3_cp0+1
+        lda #<M3_READ_MAX           ; the first block ends after 893
+        sta m3_blk_end
+        lda #>M3_READ_MAX
+        sta m3_blk_end+1
+.endif
 @p_copy:
         lda UCI_STATUS              ; ER-12: DATA_AV before EVERY byte, or a
         bpl @p_short                ;  short block reads as $00s (bit 7)
@@ -929,6 +947,38 @@ net_poll:
         bne @p_copy
         beq @p_tail                 ; always
 @p_short:
+.ifdef M3_MULTI_BLOCK
+        ; A = $DF1C, bit 7 clear: this block is read to its end and the
+        ; header still owes bytes. Take the continuation only on Data More
+        ; ("11") after a FULL block; anything else is a hole (ER-5).
+        and #UCI_STAT_STATE
+        cmp #UCI_STAT_STATE
+        bne @p_hole
+        stx m3_left
+        sty m3_left+1
+        lda @p_store+1              ; bytes so far = store - start, mod ring
+        sec
+        sbc m3_cp0
+        sta m3_got
+        lda @p_store+2              ; (>tcp_recv_buf is 0 under the mask)
+        sbc m3_cp0+1
+        and #>TCP_RECV_MASK
+        cmp m3_blk_end+1
+        bne @p_hole
+        lda m3_got
+        cmp m3_blk_end
+        bne @p_hole
+        jsr m3_next_block           ; data-accept, <= 12 s from it (ER-1)
+        bcc :+
+        jmp @p_dead_owned           ; ABORTed: $89, the bytes are lost
+:       ldx m3_left                 ; m3_blk_end stays 893: a second
+        ldy m3_left+1               ;  Data More never matches it (ER-5)
+        jmp @p_copy
+@p_hole:
+.assert (>tcp_recv_buf & >TCP_RECV_MASK) = 0, error, "@p_short drops >tcp_recv_buf by masking"
+.assert M3_READ_TOTAL <= M3_READ_MAX + M3_READ_MORE, error, "a READ is at most two blocks"
+.assert M3_READ_TOTAL <= TCP_RECV_MASK, error, "bytes so far are counted mod the ring"
+.endif
         lda #UCI_ERR_SHORT_READ     ; short of its header: a hole (ER-5)
         sta m3_bad
 @p_tail:
@@ -1364,6 +1414,12 @@ m3_rem:             .res 2
 m3_piece:           .res 2
 m3_cnt:             .res 2
 m3_wresp:           .res 2
+.ifdef M3_MULTI_BLOCK
+m3_cp0:             .res 2      ; ring tail where this READ's bytes start
+m3_blk_end:         .res 2      ; bytes in the READ when block 1 is full
+m3_left:            .res 2      ; the copy's X/Y over a continuation
+m3_got:             .res 1
+.endif
 .ifdef M3_TRACE
 m3_tr_zero:                     ; net_init zeroes these
 m3_tr_count:        .res 2      ; CONNECTED net_poll calls since net_init