ROADMAP P6b, FINDINGS 67. DLXP2: a 64-byte header and then groups -- one audio lump of A sectors, then F records -- so record i is at off_frm + i*rec + (i//F)*A*512 and lump k at off_aud + k*(F*rec + A*512). Still no index and still none needed, which is the packed branch's whole claim surviving the one change that could have ended it. The player carries the third term in six instructions once a frame and zero parsing, and 120 of 120 records are still pixel-exact off a real MB89352 volume with the interleave in, against a silent control that says no picture byte moved. The finding is what 65.3 called padding. A lump is 7,168 B of SPACE; eleven frames of audio is 7,161.4583... B, so the payload alternates 7,161 and 7,162 and the rest is zero. A player that fed the chip the whole lump -- which is what "14 sectors every 11 frames" invites -- runs 0.09% fast, and that is not waste, it is drift: 0.84 ms a group, 1.25 s of lip-sync over the game's 22.8 minutes. What a player carries is one accumulator, acc += 11*15625; n = acc//24; acc %= 24, which is clock.i's shape for clock.i's reason and the third time this tree has met the pattern. The four ADPCM axes ride in the header as fields rather than a version number, and the gate flips each one to prove they earn it: nibble order -31.99 dB, delta formula -24.86, clamp 0.00, accumulator -0.49. Nothing parses a packed container, so the gate partitions the whole file -- 131 spans, no overlap, no gap -- and asserts what a cadence-blind player would read: exactly records 11..119 wrong, and frames 0..10 identical either way, which is how an off-by-one like that survives a rig that checks frame 0. Wire 582.0 + 7.64 = 589.6 KB/s, 65.3's prediction to the tenth. Green light ALL GREEN before (tmp/check_s35_start.log) and after (tmp/check_s35_end.log), with the new stage in it. Claude-Session: https://claude.ai/code/session_01194oWYW8DQXK1SZ2DnChW6
350 lines
18 KiB
Lua
350 lines
18 KiB
Lua
-- Drive src/player/packed.s: THE DECODER-FREE PACKED PLAYER, END TO END,
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-- OFF A REAL VOLUME. ROADMAP K3.
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--
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-- WHAT THIS SCRIPT DOES NOT DO IS THE POINT OF IT. tools/bench/stream.lua
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-- pushes expanded codebooks and a packed palette into RAM, plays a transport at
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-- a modelled byte rate, and writes the frame tick. This one pushes 2,898 bytes
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-- of 68000 code and eleven mailbox words, and then READS. It moves no picture
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-- byte, models no rate, sets no CRTC register and writes no palette entry: the
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-- machine brings up its own display, builds its own chain, keeps its own clock
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-- off V-DISP and fetches every record itself with READ(10) off a CZ-6BS1.
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--
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-- SO THE GATE IS NOT THE ONE THE CODEC USES, AND IT HAD TO CHANGE.
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-- tools/bench/verify_decode.py checks ONE frame -- the last -- and that audits
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-- the whole run because the codec is temporally recursive: a SKIP block is a
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-- claim about the previous frame still being on screen, so the final frame is
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-- only right if all 120 were. A packed frame is a LITERAL. Frame 119 being
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-- pixel-exact says nothing whatever about frame 60. This script therefore
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-- snapshots EVERY frame and tools/bench/verify_packed.py compares all of them;
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-- the simplification that deleted the ring also deleted the gate's free lunch.
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--
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-- WHEN A SNAPSHOT IS TAKEN, and why not on the frame it changed. PG_SHOWN is
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-- bumped by the 68000 after it clears R20 bit 11, so a change means "a complete
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-- frame is now displayable". But MAME's screen bitmap for the host frame in
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-- progress was drawn partly before that instant, so snapshotting immediately
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-- would sample the write window -- which BLANKS the graphics layer -- for part
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-- of the picture. A 12 fps frame lasts 4 or 5 host refreshes at 56.69 Hz, so
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-- waiting SNAP_DELAY whole host frames is safely inside the slot and safely
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-- after the window closed.
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--
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-- Env:
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-- DLX_PK_HELD 1 = the channel HOLDS THE BUS (burst, max rate), 0 = it
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-- steals cycles. Not two speeds of one thing: 59.3 showed an
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-- auto-requested channel is charged by TIME, so held is the
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-- 68000 stopped for as long as the record takes to arrive.
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-- Default 1.
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-- DLX_PK_PACE 1 = the machine holds itself to the container's fps off
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-- V-DISP (default). 0 free-runs, which tests the CHAIN with
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-- the clock out of the way.
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-- DLX_PK_ITER passes over the scene (default 1). >1 exercises the seek,
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-- which for this container is arithmetic and nothing else.
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-- DLX_PK_NFR play only the first N frames (default: all of them)
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-- DLX_PK_FPS pace at this rate instead of the container's. NOT a
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-- cosmetic knob and not a way to make a number look better:
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-- under MAME the emulated transport takes about a whole 12 fps
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-- slot to deliver a 49,664 B record, and the write window has
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-- to be OPEN for all of it -- so at 12 fps there is no instant
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-- at which a complete frame is displayable and nothing can be
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-- snapshotted. Pacing slower opens a display interval without
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-- changing one byte of the transfer, which is what lets the
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-- PIXEL-EXACTNESS of all 120 frames be gated separately from
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-- the RATE the emulated transport happens to run at. The two
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-- are different questions and this is the knob that separates
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-- them.
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-- DLX_PK_CSV write the per-frame arrival series here
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M = manager.machine
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SP = M.devices[":maincpu"].spaces["program"]
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local function findfile(n)
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for _,p in ipairs{"../tools/bench/"..n, "tools/bench/"..n, n} do
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local f = io.open(p,"rb"); if f then f:close(); return p end
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end
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error(n.." not found")
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end
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local META = loadfile("packed_meta.lua")()
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-- src/player/packed.s. Inputs first, then outputs; the split is the file's.
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local PG_FLAG, PG_NFR, PG_FPS, PG_LBA0 = 0x18900, 0x18904, 0x18908, 0x1890C
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local PG_RECS, PG_PALL, PG_HELD = 0x18910, 0x18914, 0x18918
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local PG_PACEON, PG_ITER = 0x1891C, 0x18920
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local PG_CADF, PG_CADA = 0x18924, 0x18928
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local PG_SHOWN, PG_ERR, PG_ERRAT = 0x18930, 0x18934, 0x18938
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local PG_LATE, PG_LATE1, PG_LATEM = 0x1893C, 0x18940, 0x18944
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local PG_VDISP, PG_VD0, PG_TSPIN = 0x18948, 0x1894C, 0x18950
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local PG_GSPIN, PG_LOSTV, PG_ARRN = 0x18954, 0x18958, 0x1895C
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local PG_ARR = 0x1B000
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-- src/player/clock.i and src/player/scsi.i, read for diagnosis only.
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local CLK_PACE, CLK_VDISP, CLK_ERR = 0x18034, 0x18064, 0x1806C
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local SC_ERR = 0x18200
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local CRTC_R20 = 0xE80028
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local HELD = (os.getenv("DLX_PK_HELD") or "1") == "1"
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local PACED = (os.getenv("DLX_PK_PACE") or "1") == "1"
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local ITERS = tonumber(os.getenv("DLX_PK_ITER") or "") or 1
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local NFR = tonumber(os.getenv("DLX_PK_NFR") or "") or META.nframes
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local FPS = tonumber(os.getenv("DLX_PK_FPS") or "") or META.fps
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local CSV = os.getenv("DLX_PK_CSV")
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local SNAP_DELAY = 2
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local SCERRNAME = {[0]="OK", "SELECTION TIMEOUT -- no target answered",
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"UNEXPECTED PHASE", "POLL TIMEOUT -- a phase never arrived",
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"NON-ZERO SCSI STATUS",
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"WINDOWED READ REFUSED -- a channel cannot drop bytes"}
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local code do local f=assert(io.open("packed.bin","rb")); code=f:read("a"); f:close() end
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local function T() local t=M.time; return t.seconds + t.attoseconds/1e18 end
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local function P(s) print("[PK] "..s) end
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local function setup()
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for i = 1, #code do SP:write_u8(0x10000+i-1, string.byte(code,i)) end
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SP:write_u32(PG_FLAG, 0)
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SP:write_u32(PG_NFR, NFR)
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SP:write_u32(PG_FPS, FPS)
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SP:write_u32(PG_LBA0, META.lba0)
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SP:write_u32(PG_RECS, META.rec_sectors)
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SP:write_u32(PG_PALL, META.palette_last)
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SP:write_u32(PG_HELD, HELD and 1 or 0)
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SP:write_u32(PG_PACEON, PACED and 1 or 0)
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SP:write_u32(PG_ITER, ITERS)
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-- DLXP2's cadence. Zero for a silent container, and the 68000 branches on the
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-- zero: a player told the wrong cadence does not fail, it reads an audio lump
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-- as a record and paints it.
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SP:write_u32(PG_CADF, META.cad_f or 0)
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SP:write_u32(PG_CADA, META.cad_a or 0)
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SP:write_u32(PG_SHOWN, 0)
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P(string.format("packed.bin=%d B, %dx%d %d fps, %d of %d frames, %d passes",
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#code, META.W, META.H, META.fps, NFR, META.nframes, ITERS))
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local cad = ""
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if (META.cad_f or 0) > 0 then
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cad = string.format(" + (i//%d)*%d", META.cad_f, META.cad_a)
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end
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P(string.format("record %d B = %d sectors at LBA %d + i*%d%s, palette %s",
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META.rec_bytes, META.rec_sectors, META.lba0,
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META.rec_sectors, cad,
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META.palette_last == 1 and "LAST" or "FIRST"))
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if (META.cad_f or 0) > 0 then
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P(string.format("DLXP2: %d B of ADPCM at %d Hz rides in %d lumps of %d sectors, "
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.."one in front of every %d records -- the third term above is the "
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.."whole cost of it on the video path",
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META.aud_bytes, META.aud_hz, META.n_lumps, META.cad_a, META.cad_f))
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end
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P(string.format("channel: %s, %s",
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HELD and "BUS HELD (burst, max rate)" or "CYCLE STEALING",
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PACED and ("SELF-PACED at "..FPS.." fps off V-DISP"
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..(FPS ~= META.fps and (" -- NOT the container's "
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..META.fps..", see DLX_PK_FPS") or ""))
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or "FREE-RUNNING (tests the chain, not the clock)"))
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P("this script writes NO picture byte, NO palette entry and NO CRTC register: "
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.."the machine brings up its own display and fetches its own records.")
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end
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local function launch()
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local cpu = M.devices[":maincpu"]
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cpu.state["SR"].value = 0x2700 -- supervisor, all interrupts masked;
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cpu.state["SP"].value = 0x8000 -- clk_init lowers it to $2500 itself
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cpu.state["PC"].value = 0x10000
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end
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local st, t0 = "boot", nil
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local shown, pending, snaps = 0, nil, 0
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local arrive, hostfr, missed = {}, 0, 0
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-- WHICH FRAME EACH SNAPSHOT IS. MAME numbers snapshots 0000, 0001, ... in the
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-- order they were taken, and a frame that could not be sampled leaves no gap in
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-- that sequence -- so the file name is NOT the frame index and a verifier that
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-- assumed it was would compare frame 61 against record 60 and report a codec
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-- bug that is really a bookkeeping one. This is the map, written out for it.
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local snapfr = {}
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local r20seen = {}
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SUB = emu.add_machine_frame_notifier(function()
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local ok, err = pcall(function()
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local t = T()
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if st == "boot" then
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if t < 3.0 then return end
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setup(); launch(); t0 = t; st = "running"; return
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end
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if st ~= "running" then return end
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hostfr = hostfr + 1
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-- WHAT THE SCREEN MODE WAS, sampled every host frame. R20 bit 11 blanks
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-- the graphics layer, so this is the only way to see the shutter the player
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-- is running: the fraction of host frames that found the window OPEN is the
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-- fraction of the scene the display spent dark, and it is a MEASUREMENT of
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-- 47.4's cost under MAME rather than a restatement of the prior.
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local r20 = SP:read_u16(CRTC_R20)
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r20seen[#r20seen+1] = ((r20 >> 11) & 1)
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local s = SP:read_u32(PG_SHOWN)
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if s > shown then
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-- Only the LAST change matters if several landed in one host frame; that
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-- cannot happen at 12 fps on a 56.69 Hz raster, and if it ever does the
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-- gate below catches it as a missing snapshot rather than a wrong one.
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arrive[#arrive+1] = {n = s, t = t - t0}
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shown = s
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pending = SNAP_DELAY
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end
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if pending then
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pending = pending - 1
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if pending <= 0 then
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pending = nil
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if (SP:read_u16(CRTC_R20) >> 11) & 1 == 0 then
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M.video:snapshot(); snaps = snaps + 1
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snapfr[#snapfr+1] = shown - 1
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else
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-- The window was open again when the delay expired: the frame we
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-- meant to sample is being overwritten. COUNTED, NOT PRINTED -- when
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-- the transfer is longer than the slot EVERY frame misses, and 119
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-- identical lines bury the four numbers the run exists to report.
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-- The count is reported once at the end and the gate reads it there.
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missed = missed + 1
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end
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end
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end
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local flag = SP:read_u32(PG_FLAG)
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if flag ~= 1 and pending then
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-- THE LAST FRAME IS STILL PENDING. packed.s spins in pg_hold with the
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-- window CLOSED once the scene is over, so the delay can simply run out;
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-- returning here rather than reporting is what stops the final frame
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-- being the one frame the gate never sees.
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return
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end
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if flag ~= 1 then
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st = "done"
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local wall = t - t0
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P(string.format("FLAG=$%02X after %.3f s, %d frames shown, %d snapshots, "
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.."%d frames NOT SAMPLED (the write window had reopened "
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.."-- the transfer is longer than the display interval)",
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flag, wall, shown, snaps, missed))
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local err = SP:read_u32(PG_ERR)
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if err ~= 0 then
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P(string.format("TRANSPORT FAILED on frame %d: %s",
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SP:read_u32(PG_ERRAT), SCERRNAME[err] or ("code "..err)))
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end
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P(string.format("array: the 68000 built %d entries (the container wants "
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.."%d)", SP:read_u32(PG_ARRN), META.entries))
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-- The first entry, read back out of the machine's own RAM. It is the one
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-- place palette-first and palette-last are visible as a FACT rather than
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-- as a flag the rig passed in and the rig read back.
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P(string.format("chain[0] = MAR $%06X MTC %d ; chain[1] = MAR $%06X MTC %d",
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SP:read_u32(PG_ARR), SP:read_u16(PG_ARR+4),
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SP:read_u32(PG_ARR+6), SP:read_u16(PG_ARR+10)))
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if PACED then
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local vd = SP:read_u32(PG_VDISP) - SP:read_u32(PG_VD0)
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-- THE CLOCK, AGAINST THE RASTER THAT DROVE IT. CLK_VDISP counts the
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-- edges the 68000's ISR SAW. hostfr counts the frames MAME actually
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-- drew. A held channel halts the CPU, and the MFP's pending bit is one
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-- bit, so an edge that falls inside a transfer long enough to span two
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-- of them is an edge the machine can never count. Nothing in this
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-- project has ever run a transfer and a clock at once, so nothing could
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-- have seen this before.
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P(string.format("frame clock: PACE=%d ticks, V-DISP edges SEEN=%d, "
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.."host frames drawn=%d -> %d edges LOST (%.1f%%)",
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SP:read_u32(CLK_PACE), vd, hostfr, hostfr - vd,
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hostfr > 0 and (hostfr-vd)*100/hostfr or 0))
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local nlate = SP:read_u32(PG_LATE)
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P(string.format("late frames (tick already past at the gate): %d%s",
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nlate, nlate > 0 and string.format(", first %d, worst "
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.."%d ticks", SP:read_u32(PG_LATE1),
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SP:read_u32(PG_LATEM)) or ""))
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-- AND WHY `late = 0` IS NOT `on time`. The gate compares the frame
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-- index against PACE, and PACE is advanced by the ISR that the held
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-- channel stops the CPU from running. A clock that loses edges loses
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-- them from BOTH sides of the comparison, so a player whose own clock
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-- has halved still reports every frame early. The LOST figure above is
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-- the only thing in this run that can contradict it, and it comes from
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-- the host's raster count rather than from the machine.
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if hostfr - vd > 0 then
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P(string.format(" ...and %d of those ticks were never "
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.."issued, so `late=%d` is measured against a clock "
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.."running at %.1f%% of the raster. The player "
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.."believes it is at %d fps and the screen is at "
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.."%.2f.", hostfr - vd, nlate, vd*100/hostfr, FPS,
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FPS * vd / hostfr))
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end
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end
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P(string.format("CPU: %d trips round the TRANSFER wait in total, %d round "
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.."the PACE gate", SP:read_u32(PG_TSPIN),
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SP:read_u32(PG_GSPIN)))
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local open = 0
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for _,v in ipairs(r20seen) do open = open + v end
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P(string.format("WRITE WINDOW OPEN on %d of %d host frames (%.1f%%) -- "
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.."buffer mode blanks the graphics layer, so that is the "
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.."share of the scene the display spent DARK under MAME",
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open, #r20seen, #r20seen > 0 and open*100/#r20seen or 0))
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if #arrive >= 2 then
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local dts, first, last = {}, arrive[1].t, arrive[#arrive].t
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for i = 2, #arrive do dts[#dts+1] = arrive[i].t - arrive[i-1].t end
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table.sort(dts)
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-- CADENCE, AND THE GRANULARITY IT IS MEASURED AT. PG_SHOWN is sampled
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-- once per host frame, so a single inter-frame figure is quantised to
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-- 1/56.69 s = 17.6 ms and the min/median/max below are multiples of it.
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-- The MEAN over the whole run is not: the quantisation error is bounded
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-- by one host frame at each END, so over n-1 intervals it is 35 ms/(n-1)
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-- -- 0.30 ms a frame over 120. Read the mean; the spread is the
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-- sampler's, not the player's.
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local mean = (last-first)/(#arrive-1)
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P(string.format("cadence: %d frames in %.3f s = %.3f fps, mean "
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.."%.2f ms/frame (+/- %.2f ms, the sampler's); "
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.."inter-frame min %.1f median %.1f max %.1f ms",
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#arrive, last-first, (#arrive-1)/(last-first),
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mean*1000, 35.3/(#arrive-1),
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dts[1]*1000, dts[math.ceil(#dts/2)]*1000,
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dts[#dts]*1000))
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-- THE TRANSPORT'S TIME IS ONLY READABLE OFF A FREE-RUNNING RUN.
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-- Paced, the mean inter-frame IS THE PACE PERIOD: the player waits for
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-- its tick and the record's delivery hides inside the slot, so dividing
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-- the record by that mean reports the clock rather than the transport
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-- and reports it as a rate. The first cut of this script printed
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-- "297.4 KB/s" off a 6 fps gate run, which is the pace and not the
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-- disc. Free-running there is no gate and the loop is transfer-bound,
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-- so the mean is the transfer.
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if not PACED then
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P(string.format(" -> FREE-RUNNING, so the mean IS the "
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.."transport: a %d B record lands in %.2f ms, i.e. "
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.."%.1f KB/s and %.1f%% of a %d fps slot. MAME's "
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.."device models carry no transfer timing "
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.."(docs/BENCHMARK.md, 42.5), so this is a property "
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.."of the APPARATUS -- it is not W and it is not a "
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.."measurement of any medium.",
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META.rec_bytes, mean*1000,
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META.rec_bytes/mean/1024,
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mean*META.fps*100, META.fps))
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else
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-- What a paced run CAN say about the transfer, and it says it from
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-- the display rather than from the clock: the window is open for
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-- exactly as long as the record takes, so the open fraction times the
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-- slot is the transfer time, sampled at the host's frame rate.
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P(string.format(" -> PACED, so this mean is the PACE and "
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.."NOT the transport. What the run does bound is the "
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.."transfer: the window was open %.1f%% of a "
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.."%.2f ms slot = %.1f ms a record.",
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open*100/#r20seen, mean*1000,
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open/#r20seen*mean*1000))
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end
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end
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if CSV then
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local f = io.open(CSV, "w")
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f:write("frame,t_s\n")
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for _,a in ipairs(arrive) do f:write(string.format("%d,%.6f\n", a.n-1, a.t)) end
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f:close()
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P("arrivals -> "..CSV)
|
|
end
|
|
do
|
|
local f = assert(io.open("packed_snaps.csv", "w"))
|
|
f:write("snapshot,frame\n")
|
|
for i, fr in ipairs(snapfr) do
|
|
f:write(string.format("%04d,%d\n", i-1, fr))
|
|
end
|
|
f:close()
|
|
P(string.format("%d snapshots -> tmp/packed_snaps.csv", #snapfr))
|
|
end
|
|
P("done")
|
|
M:exit()
|
|
end
|
|
end)
|
|
if not ok then print("[PK] LUA ERROR: "..tostring(err)); M:exit() end
|
|
end)
|