-- Play one buffer of ADPCM nibbles on the emulated MSM6258V, from 68000 code
-- (ROADMAP P6a).  The Lua here does what Lua is allowed to do in this tree:
-- push bytes in, start the CPU, read the mailbox out.  It is NOT in the feed
-- path -- session 33's probe was, and a host that writes the data register at
-- host-frame rate is not feeding a chip that consumes at 15,625 Hz (65.5).
--
-- WHAT THE MEASUREMENT IS.  MAME's -wavwrite capture, at a sample rate chosen
-- to EQUAL the chip's stream rate so nothing resamples it, is the chip's own
-- output.  tools/bench/verify_adpcm_chip.py reads the four model axes out of it.
M = manager.machine
SP = M.devices[":maincpu"].spaces["program"]

local META = loadfile("adpcm_meta.lua")()
local AD_FLAG, AD_BUF, AD_LEN = 0x18600, 0x18604, 0x18608
local AD_MTC0, AD_CSRF, AD_CERF = 0x1860C, 0x18610, 0x18614
local AD_MTCF, AD_MARF, AD_SPIN, AD_STAT = 0x18618, 0x1861C, 0x18620, 0x18624

local code do local f=io.open("adpcmgate.bin","rb"); code=f:read("a"); f:close() end
local data do local f=io.open("adpcm_data.bin","rb"); data=f:read("a"); f:close() end

local function P(s) print("[ADP] "..s) end
local function T() local t=M.time; return t.seconds + t.attoseconds/1e18 end

local st, t0, tplay = "boot", nil, nil
SUB = emu.add_machine_frame_notifier(function()
  local ok, err = pcall(function()
    local t = T()
    if st == "boot" then
      if t < 3.0 then return end
      for i = 1, #data do SP:write_u8(META.buf + i - 1, string.byte(data, i)) end
      for i = 1, #code do SP:write_u8(0x10000 + i - 1, string.byte(code, i)) end
      SP:write_u32(AD_FLAG, 0)
      SP:write_u32(AD_BUF, META.buf)
      SP:write_u32(AD_LEN, META.nbytes)
      local cpu = M.devices[":maincpu"]
      cpu.state["SR"].value = 0x2700      -- supervisor, ALL interrupts masked
      cpu.state["SP"].value = 0x8000
      cpu.state["PC"].value = 0x10000
      P(string.format("pushed %d B of code and %d B of nibbles at 0x%X",
                      #code, META.nbytes, META.buf))
      -- THE CAPTURE'S OWN CLOCK.  The wav starts at t=0 of the run, so the host
      -- has to know when PLAY happened to find the stream in it -- but it is
      -- NOT used as the alignment: the verifier searches a small window around
      -- it, because a host frame is 17.6 ms and a sample is 64 us.
      st, t0 = "running", t
      return
    end
    if st == "running" then
      local fl = SP:read_u32(AD_FLAG)
      if fl == 2 and not tplay then
        tplay = t
        P(string.format("PLAY at t=%.4f s, chip status $%02X (bit7 clear = playing), "
                        .."MTC then = %d of %d", t, SP:read_u32(AD_STAT),
                        SP:read_u32(AD_MTC0), META.nbytes))
      end
      if fl == 0xFF or fl == 0xEE then
        P(string.format("channel finished: CSR=$%02X CER=$%02X MTC=%d MAR=$%06X "
                        .."spin=%d", SP:read_u32(AD_CSRF), SP:read_u32(AD_CERF),
                        SP:read_u32(AD_MTCF), SP:read_u32(AD_MARF),
                        SP:read_u32(AD_SPIN)))
        local dt = t - (tplay or t)
        P(string.format("%d bytes took %.4f s = %.1f B/s "
                        .."(15,625 nibbles/s wants 7,812.5)",
                        META.nbytes, dt, META.nbytes/dt))
        if fl == 0xEE then P("ERROR: the gate flagged a channel error or a timeout") end
        local f = io.open("adpcm_run.lua", "w")
        f:write(string.format("return { tplay = %.9f, ok = %s, nbytes = %d,\n"
                              .."  csr = %d, cer = %d, mtc = %d, spin = %d }\n",
                              tplay or -1, tostring(fl == 0xFF), META.nbytes,
                              SP:read_u32(AD_CSRF), SP:read_u32(AD_CERF),
                              SP:read_u32(AD_MTCF), SP:read_u32(AD_SPIN)))
        f:close()
        st = "drain"; t0 = t
        return
      end
      if t - t0 > 60 then P("TIMEOUT flag="..string.format("%08X", fl)); M:exit() end
      return
    end
    if st == "drain" then
      -- let the capture run past the end of the stream, so a truncated wav is
      -- never mistaken for a short stream
      if t - t0 < 0.3 then return end
      P("done")
      M:exit()
    end
  end)
  if not ok then print("[ADP] LUA ERROR: "..tostring(err)); M:exit() end
end)