serial improvements

build/rom_serial_pseudocode.c

@@ -89,6 +89,111 @@ extern volatile u8 MEM8[0x10000];
 #define RX_INTERBYTE_TIMEOUT MEM8[0xF9C1u]
 #define RX_COMPLETE_TIMER MEM8[0xF9C5u]
 
+/* Candidate Protocol Semantics
+ * confidence: medium-high (0.9)
+ * caveat: Semantic names are candidates only. The analyzer reports byte roles, command values, dispatch targets, and response staging patterns observed in code; it does not prove source-level intent or protocol documentation.
+ * byte layout:
+ * - byte0: op_flags (medium-high) - low three bits select a command; upper bits are preserved or gated in some paths
+ * - byte1: addr_page_flags (medium) - candidate high/page byte for logical point/index; bit 7 is tested as a control flag
+ * - byte2: addr_offset (medium) - candidate low/offset byte for logical point/index
+ * - byte3: value_hi (medium) - candidate high byte of a word value
+ * - byte4: value_lo (medium) - candidate low byte of a word value
+ * - byte5: checksum (high) - 0x5A-seeded XOR of bytes 0..4
+ * dispatch: command_low3 = RX_FRAME(0) & 0x07; observed H'00, H'01, H'02, H'04, H'05, H'06, H'07
+ * dispatch evidence: H'BC08, H'BC0C, H'BC20, H'BC22, H'BC24, H'BC26, H'BC29, H'BC2B, H'BC2E, H'BC30, H'BC45, H'BC47, H'BC4A, H'BC4C, H'BC4F, H'BC51, H'BC54, H'BC56
+ * index decoder: RX[1:2] -> logical index via loc_622B (medium)
+ * command candidates:
+ * - H'00 set_value_acked: candidate write of RX[3:4] into primary/current tables, followed by a response; handler H'BC69; responses response_at_BCCD
+ * - H'01 read_value: candidate read from the primary table, followed by a response carrying the value; handler H'BCD7; responses response_at_BCFA
+ * - H'02 clear_or_abort: candidate clear/abort path with no immediate response builder; handler H'BD04; responses none
+ * - H'04 set_value_no_immediate_reply: candidate write/update path that stores a value without an immediate serial response; handler H'BD0E; responses none
+ * - H'05 ack_or_clear_pending: candidate pending/event acknowledgement path; handler H'BD80; responses none
+ * - H'06 set_secondary_value: candidate secondary-table value write path; handler H'BDDB; responses none
+ * - H'07 retransmit_or_error_reply: candidate retransmit/NAK-style path; error handling also builds command 0x07 responses; handler H'BE05; responses response_at_BE22
+ */
+
+static u8 sci1_rx_candidate_command(void)
+{
+    return (u8)(RX_FRAME(0) & 0x07u);
+}
+
+static u16 sci1_rx_candidate_value(void)
+{
+    return (u16)(((u16)RX_FRAME(3) << 8) | RX_FRAME(4));
+}
+
+static u16 sci1_rx_candidate_logical_index(void)
+{
+    u8 page = RX_FRAME(1);
+    u8 offset = RX_FRAME(2);
+
+    if (page == 0u && offset <= 0x7Fu) {
+        return offset;
+    }
+    if (page == 1u) {
+        return (u16)(0x0080u + offset);
+    }
+    if (page == 2u && offset <= 0x7Fu) {
+        return (u16)(0x0180u + offset);
+    }
+    return 0x01FFu;
+}
+
+void sci1_process_candidate_protocol_command(void)
+{
+    u8 command = sci1_rx_candidate_command();
+    u16 logical_index = sci1_rx_candidate_logical_index();
+    u16 value = sci1_rx_candidate_value();
+
+    switch (command) {
+    case 0x00u:
+        /* set_value_acked: candidate write of RX[3:4] into primary/current tables, followed by a response
+         * evidence: H'BC08, H'BC0C, H'BC20, H'BC22, H'BCB0, H'BCB9, H'BCC1, H'BCC9, H'BCB5, H'BCBD, H'BCC5, H'BCCD
+         */
+        candidate_set_value_acked(logical_index, value);
+        break;
+    case 0x01u:
+        /* read_value: candidate read from the primary table, followed by a response carrying the value
+         * evidence: H'BC08, H'BC0C, H'BC24, H'BC26, H'BCB0, H'BCB9, H'BCC1, H'BCC9, H'BCD7, H'BCE0, H'BCE8, H'BCF0, H'BCF6, H'BCB5, H'BCBD, H'BCC5, H'BCDC, H'BCE4, H'BCFA
+         */
+        candidate_read_value(logical_index, value);
+        break;
+    case 0x02u:
+        /* clear_or_abort: candidate clear/abort path with no immediate response builder
+         * evidence: H'BC08, H'BC0C, H'BC29, H'BC2B
+         */
+        candidate_clear_or_abort(logical_index, value);
+        break;
+    case 0x04u:
+        /* set_value_no_immediate_reply: candidate write/update path that stores a value without an immediate serial response
+         * evidence: H'BC08, H'BC0C, H'BC45, H'BC47
+         */
+        candidate_set_value_no_immediate_reply(logical_index, value);
+        break;
+    case 0x05u:
+        /* ack_or_clear_pending: candidate pending/event acknowledgement path
+         * evidence: H'BC08, H'BC0C, H'BC4A, H'BC4C
+         */
+        candidate_ack_or_clear_pending(logical_index, value);
+        break;
+    case 0x06u:
+        /* set_secondary_value: candidate secondary-table value write path
+         * evidence: H'BC08, H'BC0C, H'BC4F, H'BC51
+         */
+        candidate_set_secondary_value(logical_index, value);
+        break;
+    case 0x07u:
+        /* retransmit_or_error_reply: candidate retransmit/NAK-style path; error handling also builds command 0x07 responses
+         * evidence: H'BC08, H'BC0C, H'BC2E, H'BC30, H'BC54, H'BC56, H'BE09, H'BE11, H'BE19, H'BE22
+         */
+        candidate_retransmit_or_error_reply(logical_index, value);
+        break;
+    default:
+        candidate_unknown_command(command, logical_index, value);
+        break;
+    }
+}
+
 /*
  * TX reconstruction evidence
  * candidate/evidence-supported SCI1 6-byte TX frame hypothesis using buffer H'F858-H'F85D with checksum byte H'F85D seeded by H'005A