CydandClaude Fable 5
f236d15d51
The VPX responder device now drives production BattleTech v4.10 through the full transputer/i860 boot, far past the Phase 1 wall: - iserver boot handshake solved: feeds 3 well-formed 'version' (tag 42) iserver requests, satisfying startup_handshake()'s 3 transactions. - i860 download solved: parses the outbound framed renderer messages (vr_860args/code/data/bss) and absorbs them, staying byte-aligned. - echo-action reply model validated against board source (VRENDER/VR_REMOT.C reply() echoes the received action); device tracks and echoes the last outbound action generally. Remaining sub-protocol identified and characterized: after i860 boot the host switches to a FIFO fast path (OUTSW.ASM: 0x40 tag + REP OUTSW 16-bit words to FIFO port 0x154/0x155, gated by ok_to_fifo at 0x160). The current build stops at velocirender_sync because the device only implements the slow byte path. PHASE2-PROGRESS.md documents the exact next steps (FIFO transport + render loop -> Phase 3 OpenGL backend). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
287 lines
12 KiB
C++
287 lines
12 KiB
C++
/* VPX link-adapter device (Tesla Rel 4.10 emulation)
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*
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* Impersonates the INMOS C012 transputer link adapter the Division VPX board
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* hung off the ISA bus (host source: sda4/DPL3/LINKIO.C, setLA):
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*
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* base+0 (0x150) inputData R byte board->host
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* base+1 (0x151) outputData W byte host->board
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* base+2 (0x152) inputStatus R bit0 = inbound byte available
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* base+3 (0x153) outputStatus R bit0 = ready to accept outbound byte
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* base+16 (0x160) resetRoot W board reset strobe
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* base+17 (0x161) analyseRoot W board analyse strobe
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*
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* Two modes, selected by environment variables (device inert unless VPXLOG set):
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*
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* VPXLOG=<path> Phase 1: log every access to <path>.
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* VPX_RESPOND=1 Phase 2: also answer as the transputer would, so the
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* game gets past boot_xputer()'s startup_handshake().
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* VPX_HANDSHAKES=N number of iserver transactions to feed (default 3;
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* Phil's note in VR_COMMS.C: the transputer C runtime
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* does 3 iserver transactions at startup).
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*
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* Protocol reference: sda4/DPL3/VR_COMMS.C.
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* - receive_protocol(): host reads a 4-byte little-endian length/route word
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* (bit31=iserver, bits16-23=sender, low16=payload length nb<=1040) then nb
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* payload bytes. startup_handshake() does N such reads; each is answered by
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* iserver_action() and only success is checked -- so feeding N well-formed
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* iserver "version" requests (tag 42, no request-content dependency)
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* satisfies the handshake.
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* - The monitor (VRENDMON.BTL) and i860 (VRNOSTEX.MNG) segment downloads are
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* pure host->board writes; the device just absorbs them.
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*/
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#include "dosbox.h"
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#include "inout.h"
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#include "logging.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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static const io_port_t VPX_BASE = 0x150;
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static FILE *vpx_fp = NULL; /* log file, or NULL */
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static bool vpx_respond = false;
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static int vpx_max_handshakes = 3;
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/* ---- board->host FIFO (what the emulated board sends the game) ---------- */
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static unsigned char in_fifo[64];
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static int in_len = 0, in_pos = 0;
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/* ---- boot state machine ------------------------------------------------- */
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enum Phase { P_INIT, P_HANDSHAKE, P_POSTBOOT };
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static Phase phase = P_INIT;
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static bool saw_write = false; /* game has written at least one byte */
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static int handshakes_fed = 0;
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/* ---- outbound frame parser (renderer messages, post-handshake) ---------- *
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* Wire format (VR_COMMS.C velocirender_transmit, little-endian PC path):
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* [length_word:4][action:4][data:(nb-4)] where nb = length_word & 0xffff.
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* iserver responses keep the same nb = length_word & 0xffff, so byte-count
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* alignment is preserved even when one slips through. We track the action of
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* the last complete message so the reply can echo it (the renderer echoes the
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* action it received: see velocirender_create/delete/sync in DPL_HOST.C). */
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static void flush_run(void); /* fwd decl (logging, defined below) */
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static bool parse_frames = false; /* true once handshake requests done */
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static int wf_need_len = 4; /* bytes still needed for length_word */
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static unsigned wf_lenbuf = 0, wf_lenshift = 0;
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static int wf_payload_left = -1; /* -1 => currently reading length_word */
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static int wf_action_pos = 0;
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static unsigned wf_action = 0;
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static int wf_last_nb = 0;
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static unsigned last_action = 0;
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static void parse_out_byte(unsigned char v) {
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if (wf_payload_left < 0) { /* accumulating length_word */
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wf_lenbuf |= ((unsigned)v) << wf_lenshift;
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wf_lenshift += 8;
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if (--wf_need_len == 0) {
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int nb = (int)(wf_lenbuf & 0xffff);
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wf_lenbuf = 0; wf_lenshift = 0; wf_need_len = 4;
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wf_payload_left = nb > 0 ? nb : 0;
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wf_last_nb = nb;
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wf_action_pos = 0; wf_action = 0;
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if (wf_payload_left == 0) wf_payload_left = -1; /* empty msg */
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}
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} else if (wf_payload_left > 0) { /* reading payload */
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if (wf_action_pos < 4) {
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wf_action |= ((unsigned)v) << (wf_action_pos * 8);
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wf_action_pos++;
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}
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if (--wf_payload_left == 0) {
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last_action = wf_action; /* message complete */
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/* diagnostic: log small control frames (skip 512B i860 chunks) */
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if (vpx_fp && wf_last_nb <= 64) {
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flush_run();
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fprintf(vpx_fp, "# FRAME action=%u nb=%d\n", wf_action, wf_last_nb);
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fflush(vpx_fp);
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}
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wf_payload_left = -1;
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}
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}
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}
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/* A well-formed iserver "version" request (VR_COMMS.C iserver_action case 42):
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* length_word = nb | (sender<<16) | 0x80000000, little-endian; payload = tag.
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* nb is padded even for iserver; use nb=2, payload {0x2a,0x00}. sender=0. */
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static const unsigned char VERSION_REQUEST[6] = {
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0x02, 0x00, 0x00, 0x80, /* length_word 0x80000002 LE */
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0x2a, 0x00 /* tag 42 (version) + pad */
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};
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static void queue_version_request(void) {
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memcpy(in_fifo, VERSION_REQUEST, sizeof VERSION_REQUEST);
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in_len = (int)sizeof VERSION_REQUEST;
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in_pos = 0;
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}
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/* A minimal non-iserver renderer reply for velocirender_receive() (VR_COMMS.C):
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* top bit of length_word clear (non-iserver), nb>=8, first int32 of payload =
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* action code. The post-boot vr_init reply is ignored by the caller
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* (DPL_HOST.C), so any action != vr_draw_scene_action satisfies it. */
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static int postboot_acks = 0;
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static int vpx_max_postboot_acks = 40; /* safety cap; tune via env */
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static void queue_render_ack(unsigned char action) {
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unsigned char m[12] = {
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0x08, 0x00, 0x00, 0x00, /* length_word 0x00000008 (nb=8) */
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action, 0x00, 0x00, 0x00, /* payload[0..3] = action (LE) */
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0x00, 0x00, 0x00, 0x00 /* payload[4..7] = node (unused) */
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};
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memcpy(in_fifo, m, sizeof m);
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in_len = (int)sizeof m;
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in_pos = 0;
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}
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/* ---- logging (run-length coalesced) ------------------------------------- */
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static unsigned long vpx_seq = 0;
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static io_port_t last_port = 0xFFFF; static unsigned last_val = ~0u;
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static bool last_write = false; static unsigned long last_run = 0;
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static char reg_name_buf[16];
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static const char *reg_name(io_port_t port) {
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switch (port - VPX_BASE) {
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case 0: return "inputData";
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case 1: return "outputData";
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case 2: return "inputStatus";
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case 3: return "outputStatus";
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case 16: return "resetRoot";
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case 17: return "analyseRoot";
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default:
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snprintf(reg_name_buf, sizeof reg_name_buf, "port_%03X", (unsigned)port);
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return reg_name_buf;
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}
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}
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static void flush_run(void) {
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if (last_run == 0 || vpx_fp == NULL) return;
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if (last_run == 1)
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fprintf(vpx_fp, "%8lu %s %-13s 0x%02X\n", vpx_seq++,
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last_write ? "W" : "R", reg_name(last_port), last_val & 0xFF);
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else
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fprintf(vpx_fp, "%8lu %s %-13s 0x%02X x%lu\n", vpx_seq++,
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last_write ? "W" : "R", reg_name(last_port), last_val & 0xFF, last_run);
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fflush(vpx_fp); last_run = 0;
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}
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static void record(io_port_t port, unsigned val, bool write) {
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if (vpx_fp == NULL) return;
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if (port == last_port && val == last_val && write == last_write) { last_run++; return; }
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flush_run();
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last_port = port; last_val = val; last_write = write; last_run = 1;
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io_port_t off = port - VPX_BASE;
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if (write && (off == 1 || off == 16 || off == 17)) flush_run();
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}
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static void note(const char *msg) {
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if (vpx_fp) { flush_run(); fprintf(vpx_fp, "# %s\n", msg); fflush(vpx_fp); }
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}
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/* ---- I/O handlers ------------------------------------------------------- */
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static Bitu vpx_read(Bitu port, Bitu /*iolen*/) {
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io_port_t off = (io_port_t)port - VPX_BASE;
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Bitu ret = 0xFF;
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switch (off) {
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case 3: /* outputStatus: always ready to accept a byte */
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ret = 0x01;
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break;
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case 2: /* inputStatus: bit0 = inbound byte available */
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ret = 0x00;
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if (vpx_respond) {
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if (in_pos < in_len) {
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ret = 0x01; /* still draining a queued message */
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} else {
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/* FIFO empty: decide whether to start a new transaction. */
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if (phase == P_INIT && saw_write) phase = P_HANDSHAKE;
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if (phase == P_HANDSHAKE) {
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if (handshakes_fed < vpx_max_handshakes) {
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queue_version_request();
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handshakes_fed++;
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note("feeding iserver version request");
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if (handshakes_fed >= vpx_max_handshakes)
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parse_frames = true; /* i860 dl + init now framed */
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ret = 0x01;
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} else {
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phase = P_POSTBOOT;
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note("handshake complete; entering post-boot");
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}
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}
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if (phase == P_POSTBOOT && in_pos >= in_len) {
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/* game is reading -> expects a renderer reply
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* (first is the vr_init ack after i860 boot). */
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if (postboot_acks < vpx_max_postboot_acks) {
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queue_render_ack((unsigned char)(last_action & 0xff));
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postboot_acks++;
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if (vpx_fp) { flush_run();
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fprintf(vpx_fp, "# post-boot: echo action %u\n",
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last_action); fflush(vpx_fp); }
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ret = 0x01;
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}
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}
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}
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}
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break;
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case 0: /* inputData: next byte from board->host FIFO */
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if (vpx_respond && in_pos < in_len) ret = in_fifo[in_pos++];
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else ret = 0xFF;
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break;
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default:
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ret = 0xFF;
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break;
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}
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record((io_port_t)port, (unsigned)ret, false);
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return ret;
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}
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static bool warned_iolen = false;
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static void vpx_write(Bitu port, Bitu val, Bitu iolen) {
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io_port_t off = (io_port_t)port - VPX_BASE;
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if (iolen != 1 && !warned_iolen && vpx_fp) {
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warned_iolen = true; flush_run();
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fprintf(vpx_fp, "# NOTE: non-byte write iolen=%u port=0x%03X val=0x%X\n",
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(unsigned)iolen, (unsigned)port, (unsigned)val);
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fflush(vpx_fp);
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}
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record((io_port_t)port, (unsigned)val, true);
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if (off == 16 && (val & 1)) {
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/* resetRoot asserted: board reset -> clear all state. */
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phase = P_INIT; saw_write = false; handshakes_fed = 0;
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postboot_acks = 0; in_len = in_pos = 0;
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parse_frames = false; wf_need_len = 4; wf_lenbuf = 0; wf_lenshift = 0;
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wf_payload_left = -1; wf_action_pos = 0; wf_action = 0; last_action = 0;
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note("board reset");
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} else if (off == 1) {
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saw_write = true; /* outputData: a download/response byte */
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if (parse_frames) parse_out_byte((unsigned char)val);
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}
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}
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void VPXLOG_Init(void) {
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const char *env = getenv("VPXLOG");
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if (env == NULL || env[0] == '\0') return;
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const char *path = (strchr(env, '/') || strchr(env, '\\') ||
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strchr(env, '.')) ? env : "vpxlog.txt";
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vpx_fp = fopen(path, "w");
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if (vpx_fp == NULL) { LOG_MSG("VPXLOG: cannot open '%s'", path); }
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const char *r = getenv("VPX_RESPOND");
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vpx_respond = (r && r[0] && r[0] != '0');
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const char *h = getenv("VPX_HANDSHAKES");
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if (h && atoi(h) > 0) vpx_max_handshakes = atoi(h);
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IO_RegisterReadHandler(VPX_BASE, vpx_read, IO_MB, 18);
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IO_RegisterWriteHandler(VPX_BASE, vpx_write, IO_MB, 18);
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if (vpx_fp) {
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fprintf(vpx_fp, "# VPX link adapter, base 0x%03X, respond=%d handshakes=%d\n",
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VPX_BASE, vpx_respond ? 1 : 0, vpx_max_handshakes);
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fprintf(vpx_fp, "# seq dir register value [run]\n");
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fflush(vpx_fp);
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}
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LOG_MSG("VPXLOG: base 0x%03X respond=%d handshakes=%d log='%s'",
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VPX_BASE, vpx_respond ? 1 : 0, vpx_max_handshakes, vpx_fp ? path : "(none)");
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}
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