/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
│                                                                              │
│ This program is free software; you can redistribute it and/or modify         │
│ it under the terms of the GNU General Public License as published by         │
│ the Free Software Foundation; version 2 of the License.                      │
│                                                                              │
│ This program is distributed in the hope that it will be useful, but          │
│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
│ General Public License for more details.                                     │
│                                                                              │
│ You should have received a copy of the GNU General Public License            │
│ along with this program; if not, write to the Free Software                  │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
│ 02110-1301 USA                                                               │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "dsp/tty/tty.h"
#include "libc/alg/arraylist2.h"
#include "libc/assert.h"
#include "libc/bits/safemacros.h"
#include "libc/calls/calls.h"
#include "libc/calls/ioctl.h"
#include "libc/calls/struct/iovec.h"
#include "libc/calls/struct/sigaction.h"
#include "libc/calls/struct/stat.h"
#include "libc/calls/struct/termios.h"
#include "libc/calls/struct/winsize.h"
#include "libc/calls/termios.h"
#include "libc/conv/conv.h"
#include "libc/conv/itoa.h"
#include "libc/errno.h"
#include "libc/fmt/bing.h"
#include "libc/fmt/fmt.h"
#include "libc/log/check.h"
#include "libc/log/log.h"
#include "libc/macros.h"
#include "libc/math.h"
#include "libc/mem/mem.h"
#include "libc/runtime/gc.h"
#include "libc/runtime/runtime.h"
#include "libc/sock/sock.h"
#include "libc/stdio/stdio.h"
#include "libc/str/str.h"
#include "libc/str/thompike.h"
#include "libc/str/tpdecode.h"
#include "libc/str/tpencode.h"
#include "libc/sysv/consts/auxv.h"
#include "libc/sysv/consts/ex.h"
#include "libc/sysv/consts/exit.h"
#include "libc/sysv/consts/fileno.h"
#include "libc/sysv/consts/itimer.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/consts/poll.h"
#include "libc/sysv/consts/prot.h"
#include "libc/sysv/consts/sa.h"
#include "libc/sysv/consts/sig.h"
#include "libc/sysv/consts/termios.h"
#include "libc/sysv/errfuns.h"
#include "libc/time/time.h"
#include "libc/unicode/unicode.h"
#include "libc/x/x.h"
#include "third_party/dtoa/dtoa.h"
#include "third_party/getopt/getopt.h"
#include "tool/build/lib/address.h"
#include "tool/build/lib/breakpoint.h"
#include "tool/build/lib/case.h"
#include "tool/build/lib/cga.h"
#include "tool/build/lib/demangle.h"
#include "tool/build/lib/dis.h"
#include "tool/build/lib/endian.h"
#include "tool/build/lib/fds.h"
#include "tool/build/lib/flags.h"
#include "tool/build/lib/fpu.h"
#include "tool/build/lib/high.h"
#include "tool/build/lib/loader.h"
#include "tool/build/lib/machine.h"
#include "tool/build/lib/mda.h"
#include "tool/build/lib/memory.h"
#include "tool/build/lib/modrm.h"
#include "tool/build/lib/panel.h"
#include "tool/build/lib/pml4t.h"
#include "tool/build/lib/pty.h"
#include "tool/build/lib/stats.h"
#include "tool/build/lib/syscall.h"
#include "tool/build/lib/throw.h"

#define USAGE \
  " [-?HhrRstv] [ROM] [ARGS...]\n\
\n\
DESCRIPTION\n\
\n\
  Emulates x86 Linux Programs w/ Dense Machine State Visualization\n\
  Please keep still and only watchen astaunished das blinkenlights\n\
\n\
FLAGS\n\
\n\
  -h        help\n\
  -v        verbosity\n\
  -r        real mode\n\
  -s        statistics\n\
  -H        disable highlight\n\
  -t        tui debugger mode\n\
  -R        reactive tui mode\n\
  -b ADDR   push a breakpoint\n\
  -L PATH   log file location\n\
\n\
ARGUMENTS\n\
\n\
  ROM files can be ELF or a flat αcτµαlly pδrταblε εxεcµταblε.\n\
  It should use x86_64 in accordance with the System Five ABI.\n\
  The SYSCALL ABI is defined as it is written in Linux Kernel.\n\
\n\
FEATURES\n\
\n\
  8086, 8087, i386, x86_64, SSE3, SSSE3, POPCNT, MDA, CGA, TTY\n\
\n"

#define DUMPWIDTH 64
#define DISPWIDTH 80

#define RESTART  0x001
#define REDRAW   0x002
#define CONTINUE 0x004
#define STEP     0x008
#define NEXT     0x010
#define FINISH   0x020
#define FAILURE  0x040
#define WINCHED  0x080
#define INT      0x100
#define QUIT     0x200
#define EXIT     0x400
#define ALARM    0x800

#define kXmmIntegral 0
#define kXmmDouble   1
#define kXmmFloat    2

#define kXmmDecimal 0
#define kXmmHex     1
#define kXmmChar    2

#define CTRL(C) ((C) ^ 0100)

enum Mouse {
  kMouseLeftDown = 0,
  kMouseMiddleDown = 1,
  kMouseRightDown = 2,
  kMouseLeftUp = 4,
  kMouseMiddleUp = 5,
  kMouseRightUp = 6,
  kMouseLeftDrag = 32,
  kMouseMiddleDrag = 33,
  kMouseRightDrag = 34,
  kMouseWheelUp = 64,
  kMouseWheelDown = 65,
};

struct MachineState {
  uint64_t ip;
  uint8_t cs[8];
  uint8_t ss[8];
  uint8_t es[8];
  uint8_t ds[8];
  uint8_t fs[8];
  uint8_t gs[8];
  uint8_t reg[16][8];
  uint8_t xmm[16][16];
  struct MachineFpu fpu;
  struct MachineSse sse;
};

struct Panels {
  union {
    struct {
      struct Panel disassembly;
      struct Panel breakpointshr;
      struct Panel breakpoints;
      struct Panel mapshr;
      struct Panel maps;
      struct Panel frameshr;
      struct Panel frames;
      struct Panel displayhr;
      struct Panel display;
      struct Panel registers;
      struct Panel ssehr;
      struct Panel sse;
      struct Panel codehr;
      struct Panel code;
      struct Panel readhr;
      struct Panel readdata;
      struct Panel writehr;
      struct Panel writedata;
      struct Panel stackhr;
      struct Panel stack;
    };
    struct Panel p[20];
  };
};

static const char kRegisterNames[16][4] = {
    "RAX", "RCX", "RDX", "RBX", "RSP", "RBP", "RSI", "RDI",
    "R8",  "R9",  "R10", "R11", "R12", "R13", "R14", "R15",
};

static bool react;
static bool tuimode;
static bool alarmed;
static bool colorize;
static bool mousemode;
static bool printstats;

static int tyn;
static int txn;
static int tick;
static int speed;
static int vidya;
static int ttyin;
static int focus;
static int ttyout;
static int opline;
static int action;
static int xmmdisp;
static int exitcode;
static int codezoom;
static int readzoom;
static int writezoom;
static int stackzoom;

static long rombase;
static long codesize;
static int64_t opstart;
static int64_t codestart;
static int64_t readstart;
static int64_t mapsstart;
static int64_t writestart;
static int64_t stackstart;
static int64_t framesstart;
static int64_t breakpointsstart;
static char *codepath;
static void *onbusted;
static char *statusmessage;
static struct Machine *m;
static struct MachinePty *pty;

static struct Panels pan;
static struct MachineState laststate;
static struct Breakpoints breakpoints;
static struct Elf elf[1];
static struct Dis dis[1];
static uint8_t xmmtype[16];
static uint8_t xmmsize[16];

static long double statusexpires;
static struct termios oldterm;
static char logpath[PATH_MAX];
static char systemfailure[128];
static struct sigaction oldsig[4];

static void SetupDraw(void);
static void Redraw(void);

static char *FormatDouble(char *b, double x) {
  return g_fmt(b, x);
}

static int64_t SignExtend(uint64_t x, char b) {
  char k;
  assert(1 <= b && b <= 64);
  k = 64 - b;
  return (int64_t)(x << k) >> k;
}

static void SetCarry(bool cf) {
  m->flags = SetFlag(m->flags, FLAGS_CF, cf);
}

static bool IsCall(void) {
  return (m->xedd->op.dispatch == 0x0E8 ||
          (m->xedd->op.dispatch == 0x0FF && m->xedd->op.reg == 2));
}

static bool IsLongBranch(void) {
  return m->mode != XED_MODE_LONG &&
         (m->xedd->op.dispatch == 0x0EA || m->xedd->op.dispatch == 0x09A ||
          (m->xedd->op.opcode == 0x0FF && m->xedd->op.reg == 3) ||
          (m->xedd->op.opcode == 0x0FF && m->xedd->op.reg == 5));
}

static bool IsDebugBreak(void) {
  return m->xedd->op.map == XED_ILD_MAP0 && m->xedd->op.opcode == 0xCC;
}

static bool IsRet(void) {
  switch (m->xedd->op.dispatch) {
    case 0x0C2:
    case 0x0C3:
    case 0x0CA:
    case 0x0CB:
    case 0x0CF:
      return true;
    default:
      return false;
  }
}

static int GetXmmTypeCellCount(int r) {
  switch (xmmtype[r]) {
    case kXmmIntegral:
      return 16 / xmmsize[r];
    case kXmmFloat:
      return 4;
    case kXmmDouble:
      return 2;
    default:
      unreachable;
  }
}

static uint8_t CycleXmmType(uint8_t t) {
  switch (t) {
    default:
    case kXmmIntegral:
      return kXmmFloat;
    case kXmmFloat:
      return kXmmDouble;
    case kXmmDouble:
      return kXmmIntegral;
  }
}

static uint8_t CycleXmmDisp(uint8_t t) {
  switch (t) {
    default:
    case kXmmDecimal:
      return kXmmHex;
    case kXmmHex:
      return kXmmChar;
    case kXmmChar:
      return kXmmDecimal;
  }
}

static uint8_t CycleXmmSize(uint8_t w) {
  switch (w) {
    default:
    case 1:
      return 2;
    case 2:
      return 4;
    case 4:
      return 8;
    case 8:
      return 1;
  }
}

static int GetPointerWidth(void) {
  return 2 << (m->mode & 3);
}

static int64_t GetIp(void) {
  switch (GetPointerWidth()) {
    default:
    case 8:
      return m->ip;
    case 4:
      return Read64(m->cs) + (m->ip & 0xffff);
    case 2:
      return Read64(m->cs) + (m->ip & 0xffff);
  }
}

static int64_t GetSp(void) {
  switch (GetPointerWidth()) {
    default:
    case 8:
      return Read64(m->sp);
    case 4:
      return Read64(m->ss) + Read32(m->sp);
    case 2:
      return Read64(m->ss) + Read16(m->sp);
  }
}

static void UpdateXmmTypes(int regtype, int rmtype) {
  xmmtype[RexrReg(m->xedd->op.rde)] = regtype;
  if (IsModrmRegister(m->xedd->op.rde)) {
    xmmtype[RexbRm(m->xedd->op.rde)] = rmtype;
  }
}

static void UpdateXmmSizes(int regsize, int rmsize) {
  xmmsize[RexrReg(m->xedd->op.rde)] = regsize;
  if (IsModrmRegister(m->xedd->op.rde)) {
    xmmsize[RexbRm(m->xedd->op.rde)] = rmsize;
  }
}

static void UpdateXmmType(void) {
  switch (m->xedd->op.dispatch) {
    case 0x12E:  // UCOMIS
    case 0x12F:  // COMIS
    case 0x151:  // SQRT
    case 0x152:  // RSQRT
    case 0x153:  // RCP
    case 0x158:  // ADD
    case 0x159:  // MUL
    case 0x15C:  // SUB
    case 0x15D:  // MIN
    case 0x15E:  // DIV
    case 0x15F:  // MAX
    case 0x1C2:  // CMP
      if (Osz(m->xedd->op.rde) || Rep(m->xedd->op.rde) == 2) {
        UpdateXmmTypes(kXmmDouble, kXmmDouble);
      } else {
        UpdateXmmTypes(kXmmFloat, kXmmFloat);
      }
      break;
    case 0x12A:  // CVTPI2PS,CVTSI2SS,CVTPI2PD,CVTSI2SD
      if (Osz(m->xedd->op.rde) || Rep(m->xedd->op.rde) == 2) {
        UpdateXmmSizes(8, 4);
        UpdateXmmTypes(kXmmDouble, kXmmIntegral);
      } else {
        UpdateXmmSizes(4, 4);
        UpdateXmmTypes(kXmmFloat, kXmmIntegral);
      }
      break;
    case 0x15A:  // CVT{P,S}{S,D}2{P,S}{S,D}
      if (Osz(m->xedd->op.rde) || Rep(m->xedd->op.rde) == 2) {
        UpdateXmmTypes(kXmmFloat, kXmmDouble);
      } else {
        UpdateXmmTypes(kXmmDouble, kXmmFloat);
      }
      break;
    case 0x15B:  // CVT{,T}{DQ,PS}2{PS,DQ}
      UpdateXmmSizes(4, 4);
      if (Osz(m->xedd->op.rde) || Rep(m->xedd->op.rde) == 3) {
        UpdateXmmTypes(kXmmIntegral, kXmmFloat);
      } else {
        UpdateXmmTypes(kXmmFloat, kXmmIntegral);
      }
      break;
    case 0x17C:  // HADD
    case 0x17D:  // HSUB
    case 0x1D0:  // ADDSUB
      if (Osz(m->xedd->op.rde)) {
        UpdateXmmTypes(kXmmDouble, kXmmDouble);
      } else {
        UpdateXmmTypes(kXmmFloat, kXmmFloat);
      }
      break;
    case 0x164:  // PCMPGTB
    case 0x174:  // PCMPEQB
    case 0x1D8:  // PSUBUSB
    case 0x1DA:  // PMINUB
    case 0x1DC:  // PADDUSB
    case 0x1DE:  // PMAXUB
    case 0x1E0:  // PAVGB
    case 0x1E8:  // PSUBSB
    case 0x1EC:  // PADDSB
    case 0x1F8:  // PSUBB
    case 0x1FC:  // PADDB
      UpdateXmmSizes(1, 1);
      UpdateXmmTypes(kXmmIntegral, kXmmIntegral);
      break;
    case 0x165:  // PCMPGTW
    case 0x175:  // PCMPEQW
    case 0x171:  // PSRLW,PSRAW,PSLLW
    case 0x1D1:  // PSRLW
    case 0x1D5:  // PMULLW
    case 0x1D9:  // PSUBUSW
    case 0x1DD:  // PADDUSW
    case 0x1E1:  // PSRAW
    case 0x1E3:  // PAVGW
    case 0x1E4:  // PMULHUW
    case 0x1E5:  // PMULHW
    case 0x1E9:  // PSUBSW
    case 0x1EA:  // PMINSW
    case 0x1ED:  // PADDSW
    case 0x1EE:  // PMAXSW
    case 0x1F1:  // PSLLW
    case 0x1F6:  // PSADBW
    case 0x1F9:  // PSUBW
    case 0x1FD:  // PADDW
      UpdateXmmSizes(2, 2);
      UpdateXmmTypes(kXmmIntegral, kXmmIntegral);
      break;
    case 0x166:  // PCMPGTD
    case 0x176:  // PCMPEQD
    case 0x172:  // PSRLD,PSRAD,PSLLD
    case 0x1D2:  // PSRLD
    case 0x1E2:  // PSRAD
    case 0x1F2:  // PSLLD
    case 0x1FA:  // PSUBD
    case 0x1FE:  // PADDD
      UpdateXmmSizes(4, 4);
      UpdateXmmTypes(kXmmIntegral, kXmmIntegral);
      break;
    case 0x173:  // PSRLQ,PSRLQ,PSRLDQ,PSLLQ,PSLLDQ
    case 0x1D3:  // PSRLQ
    case 0x1D4:  // PADDQ
    case 0x1F3:  // PSLLQ
    case 0x1F4:  // PMULUDQ
    case 0x1FB:  // PSUBQ
      UpdateXmmSizes(8, 8);
      UpdateXmmTypes(kXmmIntegral, kXmmIntegral);
      break;
    case 0x16B:  // PACKSSDW
    case 0x1F5:  // PMADDWD
      UpdateXmmSizes(4, 2);
      UpdateXmmTypes(kXmmIntegral, kXmmIntegral);
      break;
    case 0x163:  // PACKSSWB
    case 0x167:  // PACKUSWB
      UpdateXmmSizes(1, 2);
      UpdateXmmTypes(kXmmIntegral, kXmmIntegral);
      break;
    case 0x16F:  // MOVDQA Vdq Wdq
      if (Osz(m->xedd->op.rde) && IsModrmRegister(m->xedd->op.rde)) {
        xmmtype[RexrReg(m->xedd->op.rde)] = xmmtype[RexbRm(m->xedd->op.rde)];
        xmmsize[RexrReg(m->xedd->op.rde)] = xmmsize[RexbRm(m->xedd->op.rde)];
      }
      break;
    default:
      return;
  }
}

static void CopyMachineState(struct MachineState *ms) {
  ms->ip = m->ip;
  memcpy(ms->cs, m->cs, sizeof(m->cs));
  memcpy(ms->ss, m->ss, sizeof(m->ss));
  memcpy(ms->es, m->es, sizeof(m->es));
  memcpy(ms->ds, m->ds, sizeof(m->ds));
  memcpy(ms->fs, m->fs, sizeof(m->fs));
  memcpy(ms->gs, m->gs, sizeof(m->gs));
  memcpy(ms->reg, m->reg, sizeof(m->reg));
  memcpy(ms->xmm, m->xmm, sizeof(m->xmm));
  memcpy(&ms->fpu, &m->fpu, sizeof(m->fpu));
  memcpy(&ms->sse, &m->sse, sizeof(m->sse));
}

static void OnSigBusted(void) {
  CHECK(onbusted);
  longjmp(onbusted, 1);
}

static int VirtualBing(int64_t v) {
  int rc;
  uint8_t *p;
  jmp_buf busted;
  onbusted = busted;
  if ((p = FindReal(m, v))) {
    if (!setjmp(busted)) {
      rc = bing(p[0], 0);
    } else {
      rc = u'≀';
    }
  } else {
    rc = u'⋅';
  }
  onbusted = NULL;
  return rc;
}

static void ScrollOp(struct Panel *p, long op) {
  long n;
  opline = op;
  if ((n = p->bottom - p->top) > 1) {
    if (!(opstart + 1 <= op && op < opstart + n)) {
      opstart = MIN(MAX(0, op - n / 8), MAX(0, dis->ops.i - n));
    }
  }
}

static int TtyWriteString(const char *s) {
  return write(ttyout, s, strlen(s));
}

static void OnFeed(void) {
  TtyWriteString("\e[K\e[2J");
}

static void HideCursor(void) {
  TtyWriteString("\e[?25l");
}

static void ShowCursor(void) {
  TtyWriteString("\e[?25h");
}

static void EnableMouseTracking(void) {
  mousemode = true;
  TtyWriteString("\e[?1000;1002;1015;1006h");
}

static void DisableMouseTracking(void) {
  mousemode = false;
  TtyWriteString("\e[?1000;1002;1015;1006l");
}

static void ToggleMouseTracking(void) {
  if (mousemode) {
    DisableMouseTracking();
  } else {
    EnableMouseTracking();
  }
}

static void LeaveScreen(void) {
  TtyWriteString(gc(xasprintf("\e[%d;%dH\e[S\r\n", tyn, txn)));
}

static void GetTtySize(int fd) {
  struct winsize wsize;
  wsize.ws_row = tyn;
  wsize.ws_col = txn;
  getttysize(fd, &wsize);
  tyn = wsize.ws_row;
  txn = wsize.ws_col;
}

static void TuiRejuvinate(void) {
  struct termios term;
  DEBUGF("TuiRejuvinate");
  GetTtySize(ttyout);
  HideCursor();
  memcpy(&term, &oldterm, sizeof(term));
  term.c_cc[VMIN] = 1;
  term.c_cc[VTIME] = 1;
  term.c_iflag &= ~(INPCK | ISTRIP | PARMRK | INLCR | IGNCR | ICRNL | IXON);
  term.c_lflag &= ~(IEXTEN | ICANON | ECHO | ECHONL);
  term.c_cflag &= ~(CSIZE | PARENB);
  term.c_cflag |= CS8;
  term.c_iflag |= IUTF8;
  CHECK_NE(-1, ioctl(ttyout, TCSETS, &term));
  xsigaction(SIGBUS, OnSigBusted, SA_NODEFER, 0, NULL);
  EnableMouseTracking();
}

static void OnQ(void) {
  LOGF("OnQ");
  if (action & FAILURE) exit(1);
  action |= INT;
  breakpoints.i = 0;
}

static void OnV(void) {
  vidya = !vidya;
}

static void OnSigWinch(void) {
  action |= WINCHED;
}

static void OnSigInt(void) {
  if (tuimode) {
    action |= INT;
  } else {
    action |= EXIT;
  }
}

static void OnSigAlarm(void) {
  action |= ALARM;
}

static void OnSigCont(void) {
  TuiRejuvinate();
  SetupDraw();
  Redraw();
}

static void TtyRestore1(void) {
  DEBUGF("TtyRestore1");
  ShowCursor();
  TtyWriteString("\e[0m");
}

static void TtyRestore2(void) {
  DEBUGF("TtyRestore2");
  ioctl(ttyout, TCSETS, &oldterm);
  DisableMouseTracking();
}

static void TuiCleanup(void) {
  sigaction(SIGCONT, oldsig + 2, NULL);
  TtyRestore1();
  DisableMouseTracking();
  tuimode = false;
}

static void ResolveBreakpoints(void) {
  long i, sym;
  for (i = 0; i < breakpoints.i; ++i) {
    if (breakpoints.p[i].symbol && !breakpoints.p[i].addr) {
      if ((sym = DisFindSymByName(dis, breakpoints.p[i].symbol)) != -1) {
        breakpoints.p[i].addr = dis->syms.p[sym].addr;
      } else {
        fprintf(stderr, "error: breakpoint not found: %s\n",
                breakpoints.p[i].symbol);
        exit(1);
      }
    }
  }
}

static void BreakAtNextInstruction(void) {
  struct Breakpoint b;
  memset(&b, 0, sizeof(b));
  b.addr = GetIp() + m->xedd->length;
  b.oneshot = true;
  PushBreakpoint(&breakpoints, &b);
}

static void LoadSyms(void) {
  LoadDebugSymbols(elf);
  DisLoadElf(dis, elf);
}

static int DrainInput(int fd) {
  char buf[32];
  struct pollfd fds[1];
  for (;;) {
    fds[0].fd = fd;
    fds[0].events = POLLIN;
    if (poll(fds, ARRAYLEN(fds), 0) == -1) return -1;
    if (!(fds[0].revents & POLLIN)) break;
    if (read(fd, buf, sizeof(buf)) == -1) return -1;
  }
  return 0;
}

static int ReadCursorPosition(int *out_y, int *out_x) {
  int y, x;
  char *p, buf[32];
  if (readansi(ttyin, buf, sizeof(buf)) == 1) return -1;
  p = buf;
  if (*p == '\e') ++p;
  if (*p == '[') ++p;
  y = strtol(p, &p, 10);
  if (*p == ';') ++p;
  x = strtol(p, &p, 10);
  if (*p != 'R') return ebadmsg();
  if (out_y) *out_y = MAX(1, y) - 1;
  if (out_x) *out_x = MAX(1, x) - 1;
  return 0;
}

static int GetCursorPosition(int *out_y, int *out_x) {
  TtyWriteString("\e[6n");
  return ReadCursorPosition(out_y, out_x);
}

static int GetTerminalDimensions(int *out_y, int *out_x) {
  TtyWriteString("\e7\e[9979;9979H\e[6n\e8");
  return ReadCursorPosition(out_y, out_x);
}

void TuiSetup(void) {
  int y, x;
  bool report;
  static bool once;
  report = false;
  if (!once) {
    LOGF("loaded program %s\n%s", codepath, gc(FormatPml4t(m)));
    LoadSyms();
    ResolveBreakpoints();
    ioctl(ttyout, TCGETS, &oldterm);
    xsigaction(SIGALRM, OnSigAlarm, 0, 0, 0);
    xsigaction(SIGINT, OnSigInt, 0, 0, oldsig + 3);
    atexit(TtyRestore2);
    once = true;
    report = true;
  }
  xsigaction(SIGCONT, OnSigCont, SA_RESTART | SA_NODEFER, 0, oldsig + 2);
  CopyMachineState(&laststate);
  TuiRejuvinate();
  if (report) {
    DrainInput(ttyin);
    y = 0;
    if (GetCursorPosition(&y, NULL) != -1) {
      TtyWriteString(gc(xasprintf("\e[%dS", y)));
    }
  }
}

static void ExecSetup(void) {
  static bool once;
  if (!once) {
    if (breakpoints.i) {
      LoadSyms();
      ResolveBreakpoints();
    }
    once = true;
  }
}

static void AppendPanel(struct Panel *p, long line, const char *s) {
  if (0 <= line && line < p->bottom - p->top) {
    AppendStr(&p->lines[line], s);
  }
}

static bool IsXmmNonZero(long start, long end) {
  long i, j;
  for (i = start; i < end; ++i) {
    for (j = 0; j < 16; ++j) {
      if (m->xmm[i][j]) {
        return true;
      }
    }
  }
  return false;
}

static bool IsSegNonZero(void) {
  unsigned i;
  for (i = 0; i < 6; ++i) {
    if (Read64(GetSegment(m, 0, i))) {
      return true;
    }
  }
  return false;
}

static int PickNumberOfXmmRegistersToShow(void) {
  if (IsXmmNonZero(0, 8) || IsXmmNonZero(8, 16)) {
    if (IsXmmNonZero(8, 16)) {
      return 16;
    } else {
      return 8;
    }
  } else {
    return 0;
  }
}

static void SetupDraw(void) {
  int i, j, n, a, b, cpuy, ssey, dx[2], c2y[3], c3y[5];

  for (i = 0; i < ARRAYLEN(pan.p); ++i) {
    n = pan.p[i].bottom - pan.p[i].top;
    for (j = 0; j < n; ++j) {
      free(pan.p[i].lines[j].p);
    }
    free(pan.p[i].lines);
  }

  cpuy = 9;
  if (IsSegNonZero()) cpuy += 2;
  ssey = PickNumberOfXmmRegistersToShow();
  if (ssey) ++ssey;

  a = 12 + 1 + DUMPWIDTH;
  b = DISPWIDTH + 1;
  dx[1] = txn >= a + b ? txn - a : txn;
  dx[0] = txn >= a + b + b ? txn - a - b : dx[1];

  a = 1 / 8. * tyn;
  b = 3 / 8. * tyn;
  c2y[0] = a * .7;
  c2y[1] = a * 2;
  c2y[2] = a * 2 + b;
  if (tyn - c2y[2] > 26) {
    c2y[1] -= tyn - c2y[2] - 26;
    c2y[2] = tyn - 26;
  }
  if (tyn - c2y[2] < 26) {
    c2y[2] = tyn - 26;
  }

  a = (tyn - (cpuy + ssey) - 3) / 4;
  c3y[0] = cpuy;
  c3y[1] = cpuy + ssey;
  c3y[2] = cpuy + ssey + 1 + 1 + a * 1;
  c3y[3] = cpuy + ssey + 1 + 1 + a * 2 + 1;
  c3y[4] = cpuy + ssey + 1 + 1 + 1 + a * 3 + 1;

  /* COLUMN #1: DISASSEMBLY */

  pan.disassembly.top = 0;
  pan.disassembly.left = 0;
  pan.disassembly.bottom = tyn;
  pan.disassembly.right = dx[0];

  /* COLUMN #2: BREAKPOINTS, MEMORY MAPS, BACKTRACE, DISPLAY */

  pan.breakpointshr.top = 0;
  pan.breakpointshr.left = dx[0];
  pan.breakpointshr.bottom = 1;
  pan.breakpointshr.right = dx[1] - 1;

  pan.breakpoints.top = 1;
  pan.breakpoints.left = dx[0];
  pan.breakpoints.bottom = c2y[0];
  pan.breakpoints.right = dx[1] - 1;

  pan.mapshr.top = c2y[0];
  pan.mapshr.left = dx[0];
  pan.mapshr.bottom = c2y[0] + 1;
  pan.mapshr.right = dx[1] - 1;

  pan.maps.top = c2y[0] + 1;
  pan.maps.left = dx[0];
  pan.maps.bottom = c2y[1];
  pan.maps.right = dx[1] - 1;

  pan.frameshr.top = c2y[1];
  pan.frameshr.left = dx[0];
  pan.frameshr.bottom = c2y[1] + 1;
  pan.frameshr.right = dx[1] - 1;

  pan.frames.top = c2y[1] + 1;
  pan.frames.left = dx[0];
  pan.frames.bottom = c2y[2];
  pan.frames.right = dx[1] - 1;

  pan.displayhr.top = c2y[2];
  pan.displayhr.left = dx[0];
  pan.displayhr.bottom = c2y[2] + 1;
  pan.displayhr.right = dx[1] - 1;

  pan.display.top = c2y[2] + 1;
  pan.display.left = dx[0];
  pan.display.bottom = tyn;
  pan.display.right = dx[1] - 1;

  /* COLUMN #3: REGISTERS, VECTORS, CODE, MEMORY READS, MEMORY WRITES, STACK */

  pan.registers.top = 0;
  pan.registers.left = dx[1];
  pan.registers.bottom = c3y[0];
  pan.registers.right = txn;

  pan.ssehr.top = c3y[0];
  pan.ssehr.left = dx[1];
  pan.ssehr.bottom = c3y[0] + (ssey ? 1 : 0);
  pan.ssehr.right = txn;

  pan.sse.top = c3y[0] + (ssey ? 1 : 0);
  pan.sse.left = dx[1];
  pan.sse.bottom = c3y[1];
  pan.sse.right = txn;

  pan.codehr.top = c3y[1];
  pan.codehr.left = dx[1];
  pan.codehr.bottom = c3y[1] + 1;
  pan.codehr.right = txn;

  pan.code.top = c3y[1] + 1;
  pan.code.left = dx[1];
  pan.code.bottom = c3y[2];
  pan.code.right = txn;

  pan.readhr.top = c3y[2];
  pan.readhr.left = dx[1];
  pan.readhr.bottom = c3y[2] + 1;
  pan.readhr.right = txn;

  pan.readdata.top = c3y[2] + 1;
  pan.readdata.left = dx[1];
  pan.readdata.bottom = c3y[3];
  pan.readdata.right = txn;

  pan.writehr.top = c3y[3];
  pan.writehr.left = dx[1];
  pan.writehr.bottom = c3y[3] + 1;
  pan.writehr.right = txn;

  pan.writedata.top = c3y[3] + 1;
  pan.writedata.left = dx[1];
  pan.writedata.bottom = c3y[4];
  pan.writedata.right = txn;

  pan.stackhr.top = c3y[4];
  pan.stackhr.left = dx[1];
  pan.stackhr.bottom = c3y[4] + 1;
  pan.stackhr.right = txn;

  pan.stack.top = c3y[4] + 1;
  pan.stack.left = dx[1];
  pan.stack.bottom = tyn;
  pan.stack.right = txn;

  for (i = 0; i < ARRAYLEN(pan.p); ++i) {
    if (pan.p[i].top > pan.p[i].bottom) pan.p[i].top = pan.p[i].bottom = 0;
    if (pan.p[i].left > pan.p[i].right) pan.p[i].left = pan.p[i].right = 0;
    pan.p[i].lines =
        xcalloc(pan.p[i].bottom - pan.p[i].top, sizeof(struct Buffer));
  }

  MachinePtyResize(pty, pan.display.bottom - pan.display.top,
                   pan.display.right - pan.display.left);
}

static long Disassemble(void) {
  long lines, current;
  lines = pan.disassembly.bottom - pan.disassembly.top * 2;
  CHECK_NE(-1, Dis(dis, m, GetIp(), m->ip, lines));
  current = DisFind(dis, GetIp());
  CHECK_NE(-1, current);
  return current;
}

static long GetDisIndex(void) {
  long i;
  if ((i = DisFind(dis, GetIp())) == -1) {
    i = Disassemble();
  }
  while (i + 1 < dis->ops.i && !dis->ops.p[i].size) ++i;
  return i;
}

static void DrawDisassembly(struct Panel *p) {
  long i, j;
  for (i = 0; i < p->bottom - p->top; ++i) {
    j = opstart + i;
    if (0 <= j && j < dis->ops.i) {
      if (j == opline) AppendPanel(p, i, "\e[7m");
      AppendPanel(p, i, DisGetLine(dis, m, j));
      if (j == opline) AppendPanel(p, i, "\e[27m");
    }
  }
}

static void DrawHr(struct Panel *p, const char *s) {
  long i, wp, ws, wl, wr;
  if (p->bottom - p->top < 1) return;
  wp = p->right - p->left;
  ws = strwidth(s);
  wl = wp / 4 - ws / 2;
  wr = wp - (wl + ws);
  for (i = 0; i < wl; ++i) AppendWide(&p->lines[0], u'─');
  AppendStr(&p->lines[0], s);
  for (i = 0; i < wr; ++i) AppendWide(&p->lines[0], u'─');
  AppendStr(&p->lines[0], "\e[0m");
}

void DrawTerminal(struct Panel *p) {
  long i, y, yn;
  if (pty->conf & kMachinePtyBell) {
    if (!alarmed) {
      alarmed = true;
      setitimer(ITIMER_REAL, &((struct itimerval){{0, 0}, {0, 800000}}), NULL);
    }
    AppendStr(&pan.displayhr.lines[0], "\e[1m");
  }
  AppendStr(
      &pan.displayhr.lines[0],
      gc(xasprintf("──────────TELETYPEWRITER──%s──%s──%s──%s",
                   (pty->conf & kMachinePtyLed1) ? "\e[1;31m◎\e[0m" : "○",
                   (pty->conf & kMachinePtyLed2) ? "\e[1;32m◎\e[0m" : "○",
                   (pty->conf & kMachinePtyLed3) ? "\e[1;33m◎\e[0m" : "○",
                   (pty->conf & kMachinePtyLed4) ? "\e[1;34m◎\e[0m" : "○")));
  for (i = 36; i < pan.displayhr.right - pan.displayhr.left; ++i) {
    AppendWide(&pan.displayhr.lines[0], u'─');
  }
  for (yn = MIN(pty->yn, p->bottom - p->top), y = 0; y < yn; ++y) {
    MachinePtyAppendLine(pty, p->lines + y, y);
    AppendStr(p->lines + y, "\e[0m");
  }
}

void DrawDisplay(struct Panel *p) {
  switch (vidya) {
    case 7:
      DrawHr(&pan.displayhr, "MONOCHROME DISPLAY ADAPTER");
      DrawMda(p,
              VirtualSend(m, gc(xmalloc(25 * 80 * 2)), 0xb0000, 25 * 80 * 2));
      break;
    case 3:
      DrawHr(&pan.displayhr, "COLOR GRAPHICS ADAPTER");
      DrawCga(p,
              VirtualSend(m, gc(xmalloc(25 * 80 * 2)), 0xb8000, 25 * 80 * 2));
      break;
    default:
      DrawTerminal(p);
      break;
  }
}

static void DrawFlag(struct Panel *p, long i, char name, bool value) {
  char str[3] = "  ";
  if (value) str[1] = name;
  AppendPanel(p, i, str);
}

static void DrawRegister(struct Panel *p, long i, long r) {
  char buf[32];
  uint64_t value, previous;
  value = Read64(m->reg[r]);
  previous = Read64(laststate.reg[r]);
  if (value != previous) AppendPanel(p, i, "\e[7m");
  snprintf(buf, sizeof(buf), "%-3s", kRegisterNames[r]);
  AppendPanel(p, i, buf);
  AppendPanel(p, i, " ");
  snprintf(buf, sizeof(buf), "0x%016lx", value);
  AppendPanel(p, i, buf);
  if (value != previous) AppendPanel(p, i, "\e[27m");
  AppendPanel(p, i, "  ");
}

static void DrawSegment(struct Panel *p, long i, const uint8_t seg[8],
                        const uint8_t last[8], const char *name) {
  char buf[32];
  uint64_t value, previous;
  value = Read64(seg);
  previous = Read64(last);
  if (value != previous) AppendPanel(p, i, "\e[7m");
  snprintf(buf, sizeof(buf), "%-3s", name);
  AppendPanel(p, i, buf);
  AppendPanel(p, i, " ");
  snprintf(buf, sizeof(buf), "0x%016lx", value);
  AppendPanel(p, i, buf);
  if (value != previous) AppendPanel(p, i, "\e[27m");
  AppendPanel(p, i, "  ");
}

static void DrawSt(struct Panel *p, long i, long r) {
  char buf[32];
  long double value;
  bool isempty, changed;
  isempty = FpuGetTag(m, r) == kFpuTagEmpty;
  if (isempty) AppendPanel(p, i, "\e[38;5;241m");
  value = m->fpu.st[(r + m->fpu.sp) & 0b111];
  changed = value != laststate.fpu.st[(r + m->fpu.sp) & 0b111];
  if (!isempty && changed) AppendPanel(p, i, "\e[7m");
  snprintf(buf, sizeof(buf), "ST%d ", r);
  AppendPanel(p, i, buf);
  AppendPanel(p, i, FormatDouble(buf, value));
  if (changed) AppendPanel(p, i, "\e[27m");
  AppendPanel(p, i, "  ");
  if (isempty) AppendPanel(p, i, "\e[39m");
}

static void DrawCpu(struct Panel *p) {
  char buf[48];
  DrawRegister(p, 0, 7), DrawRegister(p, 0, 0), DrawSt(p, 0, 0);
  DrawRegister(p, 1, 6), DrawRegister(p, 1, 3), DrawSt(p, 1, 1);
  DrawRegister(p, 2, 2), DrawRegister(p, 2, 5), DrawSt(p, 2, 2);
  DrawRegister(p, 3, 1), DrawRegister(p, 3, 4), DrawSt(p, 3, 3);
  DrawRegister(p, 4, 8), DrawRegister(p, 4, 12), DrawSt(p, 4, 4);
  DrawRegister(p, 5, 9), DrawRegister(p, 5, 13), DrawSt(p, 5, 5);
  DrawRegister(p, 6, 10), DrawRegister(p, 6, 14), DrawSt(p, 6, 6);
  DrawRegister(p, 7, 11), DrawRegister(p, 7, 15), DrawSt(p, 7, 7);
  snprintf(buf, sizeof(buf), "RIP 0x%016x  FLG", m->ip);
  AppendPanel(p, 8, buf);
  DrawFlag(p, 8, 'C', GetFlag(m->flags, FLAGS_CF));
  DrawFlag(p, 8, 'P', GetFlag(m->flags, FLAGS_PF));
  DrawFlag(p, 8, 'A', GetFlag(m->flags, FLAGS_AF));
  DrawFlag(p, 8, 'Z', GetFlag(m->flags, FLAGS_ZF));
  DrawFlag(p, 8, 'S', GetFlag(m->flags, FLAGS_SF));
  DrawFlag(p, 8, 'I', GetFlag(m->flags, FLAGS_IF));
  DrawFlag(p, 8, 'D', GetFlag(m->flags, FLAGS_DF));
  DrawFlag(p, 8, 'O', GetFlag(m->flags, FLAGS_OF));
  AppendPanel(p, 8, "    ");
  if (m->fpu.ie) AppendPanel(p, 8, " IE");
  if (m->fpu.de) AppendPanel(p, 8, " DE");
  if (m->fpu.ze) AppendPanel(p, 8, " ZE");
  if (m->fpu.oe) AppendPanel(p, 8, " OE");
  if (m->fpu.ue) AppendPanel(p, 8, " UE");
  if (m->fpu.pe) AppendPanel(p, 8, " PE");
  if (m->fpu.sf) AppendPanel(p, 8, " SF");
  if (m->fpu.es) AppendPanel(p, 8, " ES");
  if (m->fpu.c0) AppendPanel(p, 8, " C0");
  if (m->fpu.c1) AppendPanel(p, 8, " C1");
  if (m->fpu.c2) AppendPanel(p, 8, " C2");
  if (m->fpu.bf) AppendPanel(p, 8, " BF");
  DrawSegment(p, 9, m->fs, laststate.fs, "FS");
  DrawSegment(p, 9, m->ds, laststate.ds, "DS");
  DrawSegment(p, 9, m->cs, laststate.cs, "CS");
  DrawSegment(p, 10, m->gs, laststate.gs, "GS");
  DrawSegment(p, 10, m->es, laststate.es, "ES");
  DrawSegment(p, 10, m->ss, laststate.ss, "SS");
}

static void DrawXmm(struct Panel *p, long i, long r) {
  float f;
  double d;
  long j, k, n;
  bool changed;
  char buf[32];
  uint8_t xmm[16];
  uint64_t ival, itmp;
  int cells, left, cellwidth, panwidth;
  memcpy(xmm, m->xmm[r], sizeof(xmm));
  changed = memcmp(xmm, laststate.xmm[r], sizeof(xmm)) != 0;
  if (changed) AppendPanel(p, i, "\e[7m");
  left = sprintf(buf, "XMM%-2d", r);
  AppendPanel(p, i, buf);
  cells = GetXmmTypeCellCount(r);
  panwidth = p->right - p->left;
  cellwidth = MIN(MAX(0, (panwidth - left) / cells - 1), sizeof(buf) - 1);
  for (j = 0; j < cells; ++j) {
    AppendPanel(p, i, " ");
    switch (xmmtype[r]) {
      case kXmmFloat:
        memcpy(&f, xmm + j * sizeof(f), sizeof(f));
        FormatDouble(buf, f);
        break;
      case kXmmDouble:
        memcpy(&d, xmm + j * sizeof(d), sizeof(d));
        FormatDouble(buf, d);
        break;
      case kXmmIntegral:
        ival = 0;
        for (k = 0; k < xmmsize[r]; ++k) {
          itmp = xmm[j * xmmsize[r] + k] & 0xff;
          itmp <<= k * 8;
          ival |= itmp;
        }
        if (xmmdisp == kXmmHex || xmmdisp == kXmmChar) {
          if (xmmdisp == kXmmChar && iswalnum(ival)) {
            sprintf(buf, "%lc", ival);
          } else {
            uint64toarray_fixed16(ival, buf, xmmsize[r] * 8);
          }
        } else {
          int64toarray_radix10(SignExtend(ival, xmmsize[r] * 8), buf);
        }
        break;
      default:
        unreachable;
    }
    buf[cellwidth] = '\0';
    AppendPanel(p, i, buf);
    n = cellwidth - strlen(buf);
    for (k = 0; k < n; ++k) {
      AppendPanel(p, i, " ");
    }
  }
  if (changed) AppendPanel(p, i, "\e[27m");
}

static void DrawSse(struct Panel *p) {
  long i;
  for (i = 0; i < MIN(16, MAX(0, p->bottom - p->top)); ++i) {
    DrawXmm(p, i, i);
  }
}

static void ScrollCode(struct Panel *p) {
  long i, n;
  n = p->bottom - p->top;
  i = GetIp() / DUMPWIDTH;
  if (!(codestart <= i && i < codestart + n)) {
    codestart = i;
  }
}

static void ScrollReadData(struct Panel *p) {
  long i, n, addr;
  n = p->bottom - p->top;
  i = m->readaddr / (DUMPWIDTH * (1 << readzoom));
  if (!(readstart <= i && i < readstart + n)) {
    readstart = i - n / 3;
  }
}

static void ScrollWriteData(struct Panel *p) {
  long i, n, addr;
  n = p->bottom - p->top;
  i = m->writeaddr / DUMPWIDTH;
  if (!(writestart <= i && i < writestart + n)) {
    writestart = i - n / 3;
  }
}

static void ScrollStack(struct Panel *p) {
  long i, n;
  n = p->bottom - p->top;
  i = GetSp() / DUMPWIDTH;
  if (!(stackstart <= i && i < stackstart + n)) {
    stackstart = i;
  }
}

static uint8_t Downsample(uint8_t al, uint8_t bl, uint8_t cl, uint8_t dl) {
  int16_t ax, bx;
  bx = bl;
  bx += cl;
  bx *= 3;
  ax = al;
  ax += dl;
  ax += bx;
  ax += 4;
  ax >>= 3;
  al = ax;
  return al;
}

static uint8_t Sharpen(uint8_t al, uint8_t bl, uint8_t cl) {
  int16_t ax, bx, cx;
  ax = al;
  bx = bl;
  cx = cl;
  ax *= -1;
  bx *= +6;
  cx *= -1;
  ax += bx;
  ax += cx;
  ax += 2;
  ax >>= 2;
  return MIN(255, MAX(0, ax));
}

static void DrawMemory(struct Panel *p, int zoom, long startline, long histart,
                       long hiend) {
  char buf[16];
  bool high, changed;
  long i, j, k, c, width;
  high = false;
  width = DUMPWIDTH * (1 << zoom);
  for (i = 0; i < p->bottom - p->top; ++i) {
    snprintf(buf, sizeof(buf), "%p ", (startline + i) * width);
    AppendStr(&p->lines[i], buf);
    for (j = 0; j < width; ++j) {
      k = (startline + i) * DUMPWIDTH + j;
      c = VirtualBing(k);
      changed = histart <= k && k < hiend;
      if (changed && !high) {
        high = true;
        AppendStr(&p->lines[i], "\e[7m");
      } else if (!changed && high) {
        AppendStr(&p->lines[i], "\e[27m");
        high = false;
      }
      AppendWide(&p->lines[i], c);
    }
    if (high) {
      AppendStr(&p->lines[i], "\e[27m");
      high = false;
    }
  }
}

static void DrawMaps(struct Panel *p) {
  int i;
  char *text, *p1, *p2;
  p1 = text = FormatPml4t(m);
  for (i = 0; p1; ++i, p1 = p2) {
    if ((p2 = strchr(p1, '\n'))) *p2++ = '\0';
    if (i >= mapsstart) {
      AppendPanel(p, i - mapsstart, p1);
    }
  }
  free(text);
}

static void DrawBreakpoints(struct Panel *p) {
  int64_t addr;
  const char *name;
  char *s, buf[256];
  long i, line, sym;
  for (line = 0, i = breakpoints.i; i--;) {
    if (breakpoints.p[i].disable) continue;
    if (line >= breakpointsstart) {
      addr = breakpoints.p[i].addr;
      sym = DisFindSym(dis, addr);
      name = sym != -1 ? dis->syms.stab + dis->syms.p[sym].name : "UNKNOWN";
      s = buf;
      s += sprintf(s, "%p ", addr);
      CHECK_LT(Demangle(s, name, DIS_MAX_SYMBOL_LENGTH), buf + ARRAYLEN(buf));
      AppendPanel(p, line - breakpointsstart, buf);
      if (sym != -1 && addr != dis->syms.p[sym].addr) {
        snprintf(buf, sizeof(buf), "+%#lx", addr - dis->syms.p[sym].addr);
        AppendPanel(p, line, buf);
      }
    }
    ++line;
  }
}

static int GetPreferredStackAlignmentMask(void) {
  switch (m->mode & 3) {
    case XED_MODE_LONG:
      return 15;
    case XED_MODE_LEGACY:
      return 3;
    case XED_MODE_REAL:
      return 3;
    default:
      unreachable;
  }
}

static void DrawFrames(struct Panel *p) {
  int i, n;
  long sym;
  uint8_t *r;
  const char *name;
  char *s, line[256];
  int64_t sp, bp, rp;
  rp = m->ip;
  bp = Read64(m->bp);
  sp = Read64(m->sp);
  for (i = 0; i < p->bottom - p->top;) {
    sym = DisFindSym(dis, rp);
    name = sym != -1 ? dis->syms.stab + dis->syms.p[sym].name : "UNKNOWN";
    s = line;
    s += sprintf(s, "%p %p ", Read64(m->ss) + bp, rp);
    s = Demangle(s, name, DIS_MAX_SYMBOL_LENGTH);
    AppendPanel(p, i - framesstart, line);
    if (sym != -1 && rp != dis->syms.p[sym].addr) {
      snprintf(line, sizeof(line), "+%#lx", rp - dis->syms.p[sym].addr);
      AppendPanel(p, i - framesstart, line);
    }
    if (!bp) break;
    if (bp < sp) {
      AppendPanel(p, i - framesstart, " [STRAY]");
    } else if (bp - sp <= 0x1000) {
      snprintf(line, sizeof(line), " %,ld bytes", bp - sp);
      AppendPanel(p, i - framesstart, line);
    }
    if (bp & GetPreferredStackAlignmentMask() && i) {
      AppendPanel(p, i - framesstart, " [MISALIGN]");
    }
    ++i;
    if (((Read64(m->ss) + bp) & 0xfff) > 0xff0) break;
    if (!(r = FindReal(m, Read64(m->ss) + bp))) {
      AppendPanel(p, i - framesstart, "CORRUPT FRAME POINTER");
      break;
    }
    sp = bp;
    bp = Read64(r + 0);
    rp = Read64(r + 8);
  }
}

static void CheckFramePointerImpl(void) {
  uint8_t *r;
  int64_t bp, sp, rp;
  static int64_t lastbp;
  bp = Read64(m->bp);
  if (bp && bp == lastbp) return;
  lastbp = bp;
  rp = m->ip;
  sp = Read64(m->sp);
  while (bp) {
    if (!(r = FindReal(m, Read64(m->ss) + bp))) {
      LOGF("corrupt frame: %p", bp);
      ThrowProtectionFault(m);
    }
    sp = bp;
    bp = Read64(r + 0) - 0;
    rp = Read64(r + 8) - 1;
    if (!bp && !(m->bofram[0] <= rp && rp <= m->bofram[1])) {
      LOGF("bad frame !(%p <= %p <= %p)", m->bofram[0], rp, m->bofram[1]);
      ThrowProtectionFault(m);
    }
  }
}

forceinline void CheckFramePointer(void) {
  if (m->bofram[0]) {
    CheckFramePointerImpl();
  }
}

static bool IsExecuting(void) {
  return (action & (CONTINUE | STEP | NEXT | FINISH)) && !(action & FAILURE);
}

static void Redraw(void) {
  int i, j;
  for (i = 0; i < ARRAYLEN(pan.p); ++i) {
    for (j = 0; j < pan.p[i].bottom - pan.p[i].top; ++j) {
      pan.p[i].lines[j].i = 0;
    }
  }
  DrawDisassembly(&pan.disassembly);
  DrawDisplay(&pan.display);
  DrawCpu(&pan.registers);
  DrawSse(&pan.sse);
  DrawHr(&pan.breakpointshr, "BREAKPOINTS");
  DrawHr(&pan.mapshr, "MAPS");
  DrawHr(&pan.frameshr, m->bofram[0] ? "PROTECTED FRAMES" : "FRAMES");
  DrawHr(&pan.ssehr, "SSE");
  DrawHr(&pan.codehr, "CODE");
  DrawHr(&pan.readhr, "READ");
  DrawHr(&pan.writehr, "WRITE");
  DrawHr(&pan.stackhr, "STACK");
  DrawMaps(&pan.maps);
  DrawFrames(&pan.frames);
  DrawBreakpoints(&pan.breakpoints);
  DrawMemory(&pan.code, codezoom, codestart, GetIp(),
             GetIp() + m->xedd->length);
  DrawMemory(&pan.readdata, readzoom, readstart, m->readaddr,
             m->readaddr + m->readsize);
  DrawMemory(&pan.writedata, writezoom, writestart, m->writeaddr,
             m->writeaddr + m->writesize);
  DrawMemory(&pan.stack, stackzoom, stackstart, GetSp(),
             GetSp() + GetPointerWidth());
  if (PrintPanels(ttyout, ARRAYLEN(pan.p), pan.p, tyn, txn) == -1) {
    LOGF("PrintPanels Interrupted");
    CHECK_EQ(EINTR, errno);
  }
  if (statusmessage && nowl() < statusexpires) {
    TtyWriteString(statusmessage);
  }
}

static void ReactiveDraw(void) {
  if (tuimode) {
    m->ip -= m->xedd->length;
    SetupDraw();
    Redraw();
    m->ip += m->xedd->length;
    tick = speed;
  }
}

static void HandleAlarm(void) {
  alarmed = false;
  action &= ~ALARM;
  pty->conf &= ~kMachinePtyBell;
  free(statusmessage);
  statusmessage = NULL;
}

static void HandleAppReadInterrupt(void) {
  DEBUGF("HandleAppReadInterrupt");
  if (action & ALARM) {
    HandleAlarm();
  }
  if (action & WINCHED) {
    GetTtySize(ttyout);
    action &= ~WINCHED;
  }
  if (action & INT) {
    action &= ~INT;
    if (action & CONTINUE) {
      action &= ~CONTINUE;
    } else {
      if (tuimode) {
        LeaveScreen();
        TuiCleanup();
      }
      exit(0);
    }
  }
}

static int OnPtyFdClose(int fd) {
  return 0;
}

static bool HasPendingInput(int fd) {
  struct pollfd fds[1];
  fds[0].fd = fd;
  fds[0].events = POLLIN;
  fds[0].revents = 0;
  poll(fds, ARRAYLEN(fds), 0);
  return fds[0].revents & (POLLIN | POLLERR);
}

static ssize_t ReadPtyFdDirect(int fd, void *data, size_t size) {
  char *buf;
  ssize_t rc;
  DEBUGF("ReadPtyFdDirect");
  buf = malloc(PAGESIZE);
  pty->conf |= kMachinePtyBlinkcursor;
  if (tuimode) DisableMouseTracking();
  for (;;) {
    ReactiveDraw();
    if ((rc = read(fd, buf, PAGESIZE)) != -1) break;
    CHECK_EQ(EINTR, errno);
    HandleAppReadInterrupt();
  }
  if (tuimode) EnableMouseTracking();
  pty->conf &= ~kMachinePtyBlinkcursor;
  if (rc > 0) {
    MachinePtyWriteInput(pty, buf, rc);
    ReactiveDraw();
    rc = MachinePtyRead(pty, data, size);
  }
  free(buf);
  return rc;
}

static ssize_t OnPtyFdReadv(int fd, const struct iovec *iov, int iovlen) {
  int i;
  ssize_t rc;
  void *data;
  size_t size;
  for (size = i = 0; i < iovlen; ++i) {
    if (iov[i].iov_len) {
      data = iov[i].iov_base;
      size = iov[i].iov_len;
      break;
    }
  }
  if (size) {
    if (!(rc = MachinePtyRead(pty, data, size))) {
      rc = ReadPtyFdDirect(fd, data, size);
    }
    return rc;
  } else {
    return 0;
  }
}

static void DrawTerminalOnly(void) {
  struct Buffer b;
  int i, y, yn, xn, tly, tlx, conf;
  conf = pty->conf & kMachinePtyNocursor;
  pty->conf |= kMachinePtyNocursor;
  memset(&b, 0, sizeof(b));
  yn = MIN(tyn, pty->yn);
  xn = MIN(txn, pty->xn);
  tly = tyn / 2 - yn / 2;
  tlx = txn / 2 - xn / 2;
  AppendStr(&b, "\e[0m\e[H");
  for (y = 0; y < tyn; ++y) {
    if (y) AppendStr(&b, "\r\n");
    if (tly <= y && y <= tly + yn) {
      for (i = 0; i < tlx; ++i) {
        AppendChar(&b, ' ');
      }
      MachinePtyAppendLine(pty, &b, y - tly);
    }
    AppendStr(&b, "\e[0m\e[K");
  }
  AppendFmt(&b, "\e[%d;%dH", tly + pty->y + 1, tlx + pty->x + 1);
  write(ttyout, b.p, b.i);
  free(b.p);
  pty->conf |= conf;
}

static ssize_t OnPtyFdWritev(int fd, const struct iovec *iov, int iovlen) {
  int i;
  size_t size;
  for (size = i = 0; i < iovlen; ++i) {
    MachinePtyWrite(pty, iov[i].iov_base, iov[i].iov_len);
    size += iov[i].iov_len;
  }
  if (!tuimode) DrawTerminalOnly();
  return size;
}

static int OnPtyFdTiocgwinsz(int fd, struct winsize *ws) {
  ws->ws_row = pty->yn;
  ws->ws_col = pty->xn;
  return 0;
}

static int OnPtyFdTcgets(int fd, struct termios *c) {
  memset(c, 0, sizeof(*c));
  if (!(pty->conf & kMachinePtyNocanon)) c->c_iflag |= ICANON;
  if (!(pty->conf & kMachinePtyNoecho)) c->c_iflag |= ECHO;
  if (!(pty->conf & kMachinePtyNoopost)) c->c_oflag |= OPOST;
  return 0;
}

static int OnPtyFdTcsets(int fd, uint64_t request, struct termios *c) {
  if (c->c_iflag & ICANON) {
    pty->conf &= ~kMachinePtyNocanon;
  } else {
    pty->conf |= kMachinePtyNocanon;
  }
  if (c->c_iflag & ECHO) {
    pty->conf &= ~kMachinePtyNoecho;
  } else {
    pty->conf |= kMachinePtyNoecho;
  }
  if (c->c_oflag & OPOST) {
    pty->conf &= ~kMachinePtyNoopost;
  } else {
    pty->conf |= kMachinePtyNoopost;
  }
  return 0;
}

static int OnPtyFdIoctl(int fd, uint64_t request, void *memory) {
  if (request == TIOCGWINSZ) {
    return OnPtyFdTiocgwinsz(fd, memory);
  } else if (request == TCGETS) {
    return OnPtyFdTcgets(fd, memory);
  } else if (request == TCSETS || request == TCSETSW || request == TCSETSF) {
    return OnPtyFdTcsets(fd, request, memory);
  } else {
    return einval();
  }
}

static const struct MachineFdCb kMachineFdCbPty = {
    .close = OnPtyFdClose,
    .readv = OnPtyFdReadv,
    .writev = OnPtyFdWritev,
    .ioctl = OnPtyFdIoctl,
};

static void LaunchDebuggerReactively(void) {
  LOGF("%s", systemfailure);
  if (tuimode) {
    action |= FAILURE;
  } else {
    if (react) {
      tuimode = true;
      action |= FAILURE;
    } else {
      fprintf(stderr, "ERROR: %s\n", systemfailure);
      exit(1);
    }
  }
}

static void OnDebug(void) {
  strcpy(systemfailure, "IT'S A TRAP");
  LaunchDebuggerReactively();
}

static void OnSegmentationFault(void) {
  snprintf(systemfailure, sizeof(systemfailure), "SEGMENTATION FAULT %p",
           m->faultaddr);
  LaunchDebuggerReactively();
}

static void OnProtectionFault(void) {
  strcpy(systemfailure, "PROTECTION FAULT");
  LaunchDebuggerReactively();
}

static void OnSimdException(void) {
  strcpy(systemfailure, "SIMD FAULT");
  LaunchDebuggerReactively();
}

static void OnUndefinedInstruction(void) {
  die();
  strcpy(systemfailure, "UNDEFINED INSTRUCTION");
  LaunchDebuggerReactively();
}

static void OnDecodeError(void) {
  strcpy(stpcpy(systemfailure, "DECODE: "),
         indexdoublenulstring(kXedErrorNames, m->xedd->op.error));
  LaunchDebuggerReactively();
}

static void OnDivideError(void) {
  strcpy(systemfailure, "DIVIDE BY ZERO OR BANE/-1");
  LaunchDebuggerReactively();
}

static void OnFpuException(void) {
  strcpy(systemfailure, "FPU EXCEPTION");
  LaunchDebuggerReactively();
}

static void OnExit(int rc) {
  exitcode = rc;
  action |= EXIT;
}

static size_t GetLastIndex(size_t size, unsigned unit, int i, unsigned limit) {
  unsigned q, r;
  if (!size) return 0;
  q = size / unit;
  r = size % unit;
  if (!r) --q;
  q += i;
  if (q > limit) q = limit;
  return q;
}

static void OnDiskServiceReset(void) {
  m->ax[1] = 0x00;
  SetCarry(false);
}

static void OnDiskServiceBadCommand(void) {
  m->ax[1] = 0x01;
  SetCarry(true);
}

static void OnDiskServiceGetParams(void) {
  size_t lastsector, lasttrack, lasthead;
  lasthead = GetLastIndex(elf->mapsize, 512 * 63 * 1024, 0, 255);
  lasttrack = GetLastIndex(elf->mapsize, 512 * 63, 0, 1023);
  lastsector = GetLastIndex(elf->mapsize, 512, 1, 63);
  m->dx[0] = 1;
  m->dx[1] = lasthead;
  m->cx[0] = lasttrack >> 8 << 6 | lastsector;
  m->cx[1] = lasttrack;
  m->ax[1] = 0;
  Write64(m->es, 0);
  Write16(m->di, 0);
  SetCarry(false);
}

static void OnDiskServiceReadSectors(void) {
  int64_t drive, head, track, sector, offset, size, addr;
  drive = m->dx[0];
  head = m->dx[1];
  track = (m->cx[0] & 0b11000000) << 2 | m->cx[1];
  sector = (m->cx[0] & 0b00111111) - 1;
  offset = head * track * sector * 512;
  size = m->ax[0] * 512;
  offset = sector * 512 + track * 512 * 63 + head * 512 * 63 * 1024;
  if (0 <= sector && offset + size <= elf->mapsize) {
    addr = Read64(m->es) + Read16(m->bx);
    if (addr + size <= 0xffff0 + 0xffff + 1) {
      SetWriteAddr(m, addr, size);
      VirtualRecv(m, addr, elf->map + offset, size);
      m->ax[1] = 0x00;
      SetCarry(false);
    } else {
      m->ax[0] = 0x00;
      m->ax[1] = 0x02;
      SetCarry(true);
    }
  } else {
    m->ax[0] = 0x00;
    m->ax[1] = 0x0d;
    SetCarry(true);
  }
}

static void OnDiskService(void) {
  switch (m->ax[1]) {
    case 0x00:
      OnDiskServiceReset();
      break;
    case 0x02:
      OnDiskServiceReadSectors();
      break;
    case 0x08:
      OnDiskServiceGetParams();
      break;
    default:
      OnDiskServiceBadCommand();
      break;
  }
}

static void OnVidyaServiceSetMode(void) {
  if (FindReal(m, 0xB0000)) {
    vidya = m->ax[0];
  } else {
    WARNF("maybe you forgot -r flag");
  }
}

static void OnVidyaServiceGetMode(void) {
  m->ax[0] = vidya;
  m->ax[1] = 80;  // columns
  m->bx[1] = 0;   // page
}

static void OnVidyaServiceSetCursorPosition(void) {
  MachinePtySetY(pty, m->dx[1]);
  MachinePtySetX(pty, m->dx[0]);
}

static void OnVidyaServiceGetCursorPosition(void) {
  m->dx[1] = pty->y;
  m->dx[0] = pty->x;
  m->cx[1] = 5;  // cursor ▂ scan lines 5..7 of 0..7
  m->cx[0] = 7 | !!(pty->conf & kMachinePtyNocursor) << 5;
}

static int GetVidyaByte(unsigned char b) {
  if (0x20 <= b && b <= 0x7F) return b;
  if (b == 0xFF) b = 0x00;
  return kCp437[b];
}

static void OnVidyaServiceWriteCharacter(void) {
  int i, n, y, x;
  char *p, buf[32];
  p = buf;
  p += FormatCga(m->bx[0], p);
  p = stpcpy(p, "\e7");
  p += tpencode(p, 8, GetVidyaByte(m->ax[0]), false);
  p = stpcpy(p, "\e8");
  for (i = Read16(m->cx); i--;) {
    MachinePtyWrite(pty, buf, p - buf);
  }
}

static char16_t VidyaServiceXlatTeletype(uint8_t c) {
  switch (c) {
    case '\a':
    case '\b':
    case '\r':
    case '\n':
    case 0177:
      return c;
    default:
      return GetVidyaByte(c);
  }
}

static void OnVidyaServiceTeletypeOutput(void) {
  int n;
  char buf[12];
  n = FormatCga(m->bx[0], buf);
  n += tpencode(buf + n, 6, VidyaServiceXlatTeletype(m->ax[0]), false);
  MachinePtyWrite(pty, buf, n);
}

static void OnVidyaService(void) {
  switch (m->ax[1]) {
    case 0x00:
      OnVidyaServiceSetMode();
      break;
    case 0x02:
      OnVidyaServiceSetCursorPosition();
      break;
    case 0x03:
      OnVidyaServiceGetCursorPosition();
      break;
    case 0x09:
      OnVidyaServiceWriteCharacter();
      break;
    case 0x0E:
      OnVidyaServiceTeletypeOutput();
      break;
    case 0x0F:
      OnVidyaServiceGetMode();
      break;
    default:
      break;
  }
}

static void OnKeyboardServiceReadKeyPress(void) {
  uint8_t b;
  ssize_t rc;
  pty->conf |= kMachinePtyBlinkcursor;
  if (tuimode) DisableMouseTracking();
  for (;;) {
    ReactiveDraw();
    if ((rc = read(0, &b, 1)) != -1) break;
    CHECK_EQ(EINTR, errno);
    HandleAppReadInterrupt();
  }
  if (tuimode) EnableMouseTracking();
  pty->conf &= ~kMachinePtyBlinkcursor;
  ReactiveDraw();
  if (b == 0x7F) b = '\b';
  m->ax[0] = b;
  m->ax[1] = 0;
}

static void OnKeyboardService(void) {
  switch (m->ax[1]) {
    case 0x00:
      OnKeyboardServiceReadKeyPress();
      break;
    default:
      break;
  }
}

static void OnApmService(void) {
  if (Read16(m->ax) == 0x5300 && Read16(m->bx) == 0x0000) {
    Write16(m->bx, 'P' << 8 | 'M');
    SetCarry(false);
  } else if (Read16(m->ax) == 0x5301 && Read16(m->bx) == 0x0000) {
    SetCarry(false);
  } else if (Read16(m->ax) == 0x5307 && m->bx[0] == 1 && m->cx[0] == 3) {
    LOGF("APM SHUTDOWN");
    exit(0);
  } else {
    SetCarry(true);
  }
}

static void OnE820(void) {
  uint8_t p[20];
  if (Read32(m->dx) == 0x534D4150 && Read32(m->cx) == 24) {
    if (!Read32(m->bx)) {
      Write64(p + 000, 0);
      Write64(p + 010, BIGPAGESIZE);
      Write32(p + 014, 1);
      VirtualRecv(m, Read64(m->es) + Read16(m->di), p, sizeof(p));
      Write32(m->cx, sizeof(p));
      Write32(m->bx, 1);
    } else {
      Write32(m->bx, 0);
      Write32(m->cx, 0);
    }
    Write32(m->ax, 0x534D4150);
    SetCarry(false);
  } else {
    SetCarry(true);
  }
}

static void OnInt15h(void) {
  if (Read32(m->ax) == 0xE820) {
    OnE820();
  } else if (m->ax[1] == 0x53) {
    OnApmService();
  } else {
    SetCarry(true);
  }
}

static bool OnHalt(int interrupt) {
  ReactiveDraw();
  switch (interrupt) {
    case 1:
    case 3:
      OnDebug();
      return false;
    case 0x13:
      OnDiskService();
      return true;
    case 0x10:
      OnVidyaService();
      return true;
    case 0x15:
      OnInt15h();
      return true;
    case 0x16:
      OnKeyboardService();
      return true;
    case kMachineSegmentationFault:
      OnSegmentationFault();
      return false;
    case kMachineProtectionFault:
      OnProtectionFault();
      return false;
    case kMachineSimdException:
      OnSimdException();
      return false;
    case kMachineUndefinedInstruction:
      OnUndefinedInstruction();
      return false;
    case kMachineDecodeError:
      OnDecodeError();
      return false;
    case kMachineDivideError:
      OnDivideError();
      return false;
    case kMachineFpuException:
      OnFpuException();
      return false;
    case kMachineExit:
    case kMachineHalt:
    default:
      OnExit(interrupt);
      return false;
  }
}

static void OnPageUp(void) {
  opstart -= tyn / 2;
}

static void OnPageDown(void) {
  opstart += tyn / 2;
}

static void SetStatus(const char *fmt, ...) {
  char *s;
  va_list va;
  int y, x, n;
  va_start(va, fmt);
  s = gc(xvasprintf(fmt, va));
  va_end(va);
  n = strwidth(s);
  y = tyn - (n / txn + 1);
  x = txn / 2 - n / 2;
  free(statusmessage);
  statusmessage = xasprintf("\e[0m\e[%d;%dH%s", y + 1, x + 1, s);
  TtyWriteString(statusmessage);
  setitimer(ITIMER_REAL, &((struct itimerval){{0, 0}, {1, 0}}), NULL);
  statusexpires = nowl() + 1;
}

static void OnTurbo(void) {
  if (speed >= -1) {
    speed = MIN(0x40000000, MAX(1, speed) << 1);  // 1..40mips skip
  } else {
    speed >>= 1;
  }
  SetStatus("speed %,d", speed);
}

static void OnSlowmo(void) {
  if (speed > 0) {
    speed >>= 1;
  } else {
    speed = MAX(-(5 * 1000), MIN(-1, speed) << 1);  // 1ms..5s delay
  }
  SetStatus("speed %,d", speed);
}

static void OnUpArrow(void) {
  --opstart;
}

static void OnDownArrow(void) {
  ++opstart;
}

static void OnHome(void) {
  opstart = 0;
}

static void OnEnd(void) {
  opstart = dis->ops.i - (pan.disassembly.bottom - pan.disassembly.top);
}

static void OnEnter(void) {
  action &= ~FAILURE;
}

static void OnTab(void) {
  focus = (focus + 1) % ARRAYLEN(pan.p);
}

static void OnUp(void) {
}

static void OnDown(void) {
}

static void OnStep(void) {
  if (action & FAILURE) return;
  action |= STEP;
  action &= ~NEXT;
  action &= ~CONTINUE;
}

static void OnNext(void) {
  if (action & FAILURE) return;
  action ^= NEXT;
  action &= ~STEP;
  action &= ~FINISH;
  action &= ~CONTINUE;
}

static void OnFinish(void) {
  if (action & FAILURE) return;
  action ^= FINISH;
  action &= ~NEXT;
  action &= ~FAILURE;
  action &= ~CONTINUE;
}

static void OnContinue(void) {
  action ^= CONTINUE;
  action &= ~STEP;
  action &= ~NEXT;
  action &= ~FINISH;
  action &= ~FAILURE;
}

static void OnQuit(void) {
  action |= QUIT;
}

static void OnRestart(void) {
  action |= RESTART;
}

static void OnXmmType(void) {
  uint8_t t;
  unsigned i;
  t = CycleXmmType(xmmtype[0]);
  for (i = 0; i < 16; ++i) {
    xmmtype[i] = t;
  }
}

static void SetXmmSize(int bytes) {
  unsigned i;
  for (i = 0; i < 16; ++i) {
    xmmsize[i] = bytes;
  }
}

static void SetXmmDisp(int disp) {
  xmmdisp = disp;
}

static void OnXmmSize(void) {
  SetXmmSize(CycleXmmSize(xmmsize[0]));
}

static void OnXmmDisp(void) {
  SetXmmDisp(CycleXmmDisp(xmmdisp));
}

static bool HasPendingKeyboard(void) {
  return HasPendingInput(ttyin);
}

static void Sleep(int ms) {
  poll((struct pollfd[]){{ttyin, POLLIN}}, 1, ms);
}

static void OnMouse(char *p) {
  enum Mouse e;
  int i, x, y, dy;
  struct Panel *ep;
  e = strtol(p, &p, 10);
  if (*p == ';') ++p;
  x = min(txn, max(1, strtol(p, &p, 10))) - 1;
  if (*p == ';') ++p;
  y = min(tyn, max(1, strtol(p, &p, 10))) - 1;
  e |= (*p == 'm') << 2;
  for (ep = 0, i = 0; i < ARRAYLEN(pan.p); ++i) {
    if ((pan.p[i].left <= x && x < pan.p[i].right) &&
        (pan.p[i].top <= y && y < pan.p[i].bottom)) {
      ep = &pan.p[i];
      break;
    }
  }
  if (ep) {
    dy = 3;
    switch (e) {
      case kMouseWheelUp:
        if (ep == &pan.disassembly) opstart -= dy;
        if (ep == &pan.code) codestart -= dy;
        if (ep == &pan.readdata) readstart -= dy;
        if (ep == &pan.writedata) writestart -= dy;
        if (ep == &pan.stack) stackstart -= dy;
        if (ep == &pan.maps) mapsstart = MAX(0, mapsstart - 1);
        if (ep == &pan.frames) framesstart = MAX(0, framesstart - 1);
        if (ep == &pan.breakpoints) {
          breakpointsstart = MAX(0, breakpointsstart - 1);
        }
        break;
      case kMouseWheelDown:
        if (ep == &pan.disassembly) opstart += dy;
        if (ep == &pan.code) codestart += dy;
        if (ep == &pan.readdata) readstart += dy;
        if (ep == &pan.writedata) writestart += dy;
        if (ep == &pan.stack) stackstart += dy;
        if (ep == &pan.maps) mapsstart += 1;
        if (ep == &pan.frames) framesstart += 1;
        if (ep == &pan.breakpoints) breakpointsstart += 1;
        break;
      default:
        break;
    }
  }
}

static void ReadKeyboard(void) {
  char buf[64], *p = buf;
  if (readansi(ttyin, buf, sizeof(buf)) == -1) {
    if (errno == EINTR) return;
    FATALF("readkeyboard failed: %s", strerror(errno));
  }
  switch (*p++) {
    CASE('q', OnQ());
    CASE('v', OnV());
    CASE('s', OnStep());
    CASE('n', OnNext());
    CASE('f', OnFinish());
    CASE('c', OnContinue());
    CASE('R', OnRestart());
    CASE('x', OnXmmDisp());
    CASE('t', OnXmmType());
    CASE('T', OnXmmSize());
    CASE('u', OnUp());
    CASE('d', OnDown());
    CASE('B', PopBreakpoint(&breakpoints));
    CASE('M', ToggleMouseTracking());
    CASE('\t', OnTab());
    CASE('\r', OnEnter());
    CASE('\n', OnEnter());
    CASE(CTRL('C'), OnSigInt());
    CASE(CTRL('D'), OnSigInt());
    CASE(CTRL('\\'), OnQuit());
    CASE(CTRL('Z'), raise(SIGSTOP));
    CASE(CTRL('L'), OnFeed());
    CASE(CTRL('P'), OnUpArrow());
    CASE(CTRL('N'), OnDownArrow());
    CASE(CTRL('V'), OnPageDown());
    CASE(CTRL('T'), OnTurbo());
    case '\e':
      switch (*p++) {
        CASE('v', OnPageUp());
        CASE('t', OnSlowmo());
        case '[':
          switch (*p++) {
            CASE('<', OnMouse(p));
            CASE('A', OnUpArrow());
            CASE('B', OnDownArrow());
            CASE('F', OnEnd());
            CASE('H', OnHome());
            case '1':
              switch (*p++) {
                CASE('~', OnHome());
                default:
                  break;
              }
              break;
            case '4':
              switch (*p++) {
                CASE('~', OnEnd());
                default:
                  break;
              }
              break;
            case '5':
              switch (*p++) {
                CASE('~', OnPageUp());
                default:
                  break;
              }
              break;
            case '6':
              switch (*p++) {
                CASE('~', OnPageDown());
                default:
                  break;
              }
              break;
            case '7':
              switch (*p++) {
                CASE('~', OnHome());
                default:
                  break;
              }
              break;
            case '8':
              switch (*p++) {
                CASE('~', OnEnd());
                default:
                  break;
              }
              break;
            default:
              break;
          }
          break;
        default:
          break;
      }
      break;
    default:
      break;
  }
}

static int64_t ParseHexValue(const char *s) {
  char *ep;
  int64_t x;
  x = strtoll(s, &ep, 16);
  if (*ep) {
    fputs("ERROR: bad hexadecimal: ", stderr);
    fputs(s, stderr);
    fputc('\n', stderr);
    exit(EXIT_FAILURE);
  }
  return x;
}

static void HandleBreakpointFlag(const char *s) {
  struct Breakpoint b;
  memset(&b, 0, sizeof(b));
  if (isdigit(*s)) {
    b.addr = ParseHexValue(s);
  } else {
    b.symbol = optarg;
  }
  PushBreakpoint(&breakpoints, &b);
}

static noreturn void PrintUsage(int rc, FILE *f) {
  fprintf(f, "SYNOPSIS\n\n  %s%s", program_invocation_name, USAGE);
  exit(rc);
}

static void Exec(void) {
  long op;
  ssize_t bp;
  int interrupt;
  ExecSetup();
  if (!(interrupt = setjmp(m->onhalt))) {
    if (!(action & CONTINUE) &&
        (bp = IsAtBreakpoint(&breakpoints, GetIp())) != -1) {
      LOGF("BREAK %p", breakpoints.p[bp].addr);
      tuimode = true;
      LoadInstruction(m);
      ExecuteInstruction(m);
      CheckFramePointer();
      ops++;
    } else {
      action &= ~CONTINUE;
      for (;;) {
        LoadInstruction(m);
        ExecuteInstruction(m);
      KeepGoing:
        CheckFramePointer();
        ops++;
        if (action || breakpoints.i) {
          if (action & EXIT) {
            LOGF("EXEC EXIT");
            break;
          }
          if (action & INT) {
            LOGF("EXEC INT");
            if (react) {
              LOGF("REACT");
              action &= ~(INT | STEP | FINISH | NEXT);
              tuimode = true;
            }
            break;
          }
          if ((bp = IsAtBreakpoint(&breakpoints, GetIp())) != -1) {
            LOGF("BREAK %p", breakpoints.p[bp].addr);
            tuimode = true;
            break;
          }
        }
      }
    }
  } else {
    if (OnHalt(interrupt)) {
      goto KeepGoing;
    }
  }
}

static void Tui(void) {
  long op;
  ssize_t bp;
  int interrupt;
  bool interactive;
  LOGF("TUI");
  TuiSetup();
  SetupDraw();
  ScrollOp(&pan.disassembly, GetDisIndex());
  if (!(interrupt = setjmp(m->onhalt))) {
    for (;;) {
      if (!(action & FAILURE)) {
        LoadInstruction(m);
        UpdateXmmType();
      } else {
        m->xedd = (struct XedDecodedInst *)m->icache[0];
        m->xedd->length = 1;
        m->xedd->bytes[0] = 0xCC;
        m->xedd->op.opcode = 0xCC;
      }
      if (action & WINCHED) {
        GetTtySize(ttyout);
        action &= ~WINCHED;
      }
      interactive = ++tick > speed;
      if (interactive && speed < 0) {
        Sleep(-speed);
      }
      if (action & ALARM) {
        HandleAlarm();
      }
      if (action & FAILURE) {
        ScrollCode(&pan.code);
        ScrollStack(&pan.stack);
        ScrollReadData(&pan.readdata);
        ScrollWriteData(&pan.writedata);
      }
      if (!(action & CONTINUE) || interactive) {
        tick = 0;
        GetDisIndex();
        SetupDraw();
        Redraw();
      }
      if (action & FAILURE) {
        LOGF("TUI FAILURE");
        PrintMessageBox(ttyout, systemfailure, tyn, txn);
        ReadKeyboard();
      } else if (!IsExecuting() || (!(action & CONTINUE) && !(action & INT) &&
                                    HasPendingKeyboard())) {
        ReadKeyboard();
      }
      if (action & INT) {
        LOGF("TUI INT");
        action &= ~INT;
        if (action & (CONTINUE | NEXT | FINISH)) {
          action &= ~(CONTINUE | NEXT | FINISH);
        } else {
          tuimode = false;
          action |= CONTINUE;
          break;
        }
      }
      if (action & EXIT) {
        LeaveScreen();
        LOGF("TUI EXIT");
        break;
      }
      if (action & QUIT) {
        LOGF("TUI QUIT");
        action &= ~QUIT;
        raise(SIGQUIT);
        continue;
      }
      if (action & RESTART) {
        LOGF("TUI RESTART");
        break;
      }
      if (IsExecuting()) {
        op = GetDisIndex();
        ScrollOp(&pan.disassembly, op);
        VERBOSEF("%s", DisGetLine(dis, m, op));
        CopyMachineState(&laststate);
        if (!(action & CONTINUE)) {
          action &= ~STEP;
          if (action & NEXT) {
            action &= ~NEXT;
            if (IsCall()) {
              BreakAtNextInstruction();
              break;
            }
          }
          if (action & FINISH) {
            if (IsCall()) {
              BreakAtNextInstruction();
              break;
            } else if (IsRet()) {
              action &= ~FINISH;
            }
          }
        }
        if (!IsDebugBreak()) {
          ExecuteInstruction(m);
          if (!(action & CONTINUE) || interactive) {
            ScrollCode(&pan.code);
            ScrollStack(&pan.stack);
            ScrollReadData(&pan.readdata);
            ScrollWriteData(&pan.writedata);
          }
          if (IsLongBranch()) {
            Disassemble();
          }
        } else {
          m->ip += m->xedd->length;
          action &= ~NEXT;
          action &= ~FINISH;
          action &= ~CONTINUE;
        }
      KeepGoing:
        CheckFramePointer();
        ops++;
        if (!(action & CONTINUE)) {
          ScrollOp(&pan.disassembly, GetDisIndex());
          if ((action & FINISH) && IsRet()) action &= ~FINISH;
          if (((action & NEXT) && IsRet()) || (action & FINISH)) {
            action &= ~NEXT;
          }
        }
        if ((action & (FINISH | NEXT | CONTINUE)) &&
            (bp = IsAtBreakpoint(&breakpoints, GetIp())) != -1) {
          action &= ~(FINISH | NEXT | CONTINUE);
          LOGF("BREAK %p", breakpoints.p[bp].addr);
          break;
        }
      }
    }
  } else {
    if (OnHalt(interrupt)) {
      goto KeepGoing;
    }
    ScrollOp(&pan.disassembly, GetDisIndex());
  }
  TuiCleanup();
}

static void GetOpts(int argc, char *argv[]) {
  int opt;
  stpcpy(stpcpy(stpcpy(logpath, kTmpPath), basename(argv[0])), ".log");
  while ((opt = getopt(argc, argv, "hvtrRsb:HL:")) != -1) {
    switch (opt) {
      case 't':
        tuimode = true;
        break;
      case 'R':
        react = true;
        break;
      case 'r':
        m->mode = XED_MACHINE_MODE_REAL;
        g_disisprog_disable = true;
        break;
      case 's':
        printstats = true;
        break;
      case 'b':
        HandleBreakpointFlag(optarg);
        break;
      case 'H':
        memset(&g_high, 0, sizeof(g_high));
        break;
      case 'v':
        ++g_loglevel;
        break;
      case 'L':
        strcpy(logpath, optarg);
        break;
      case 'h':
        PrintUsage(EXIT_SUCCESS, stdout);
      default:
        PrintUsage(EX_USAGE, stderr);
    }
  }
  g_logfile = fopen(logpath, "a");
  setvbuf(g_logfile, xmalloc(PAGESIZE), _IOLBF, PAGESIZE);
}

int Emulator(int argc, char *argv[]) {
  void *code;
  int rc, fd;
  codepath = argv[optind++];
  pty = MachinePtyNew();
  m->fds.p = xcalloc((m->fds.n = 8), sizeof(struct MachineFd));
Restart:
  action = 0;
  LoadProgram(m, codepath, argv + optind, environ, elf);
  m->fds.i = 3;
  m->fds.p[0].fd = STDIN_FILENO;
  m->fds.p[0].cb = &kMachineFdCbHost;
  m->fds.p[1].fd = STDOUT_FILENO;
  m->fds.p[1].cb = &kMachineFdCbHost;
  m->fds.p[2].fd = STDERR_FILENO;
  m->fds.p[2].cb = &kMachineFdCbHost;
  if (tuimode) {
    ttyin = isatty(0) ? 0 : open("/dev/tty", O_RDWR | O_NOCTTY);
    ttyout = isatty(1) ? 1 : open("/dev/tty", O_RDWR | O_NOCTTY);
  } else {
    ttyin = -1;
    ttyout = -1;
  }
  if (ttyout != -1) {
    atexit(TtyRestore1);
    xsigaction(SIGWINCH, OnSigWinch, 0, 0, 0);
    tyn = 24;
    txn = 80;
    GetTtySize(ttyout);
    if (isatty(0)) {
      m->fds.p[0].fd = 0;
      m->fds.p[0].cb = &kMachineFdCbPty;
    }
    if (isatty(1)) {
      m->fds.p[1].fd = 1;
      m->fds.p[1].cb = &kMachineFdCbPty;
    }
    if (isatty(2)) {
      m->fds.p[2].fd = 2;
      m->fds.p[2].cb = &kMachineFdCbPty;
    }
  }
  while (!(action & EXIT)) {
    if (!tuimode) {
      Exec();
    } else {
      Tui();
    }
    if (action & RESTART) {
      goto Restart;
    }
  }
  if (tuimode) {
    LeaveScreen();
  }
  if (printstats) {
    fprintf(stderr, "taken:  %,ld\n", taken);
    fprintf(stderr, "ntaken: %,ld\n", ntaken);
    fprintf(stderr, "ops:    %,ld\n", ops);
  }
  munmap(elf->ehdr, elf->size);
  DisFree(dis);
  return exitcode;
}

static void OnlyRunOnFirstCpu(void) {
  uint64_t bs = 1;
  sched_setaffinity(0, sizeof(bs), &bs);
}

int main(int argc, char *argv[]) {
  m = NewMachine();
  speed = 16;
  SetXmmSize(2);
  SetXmmDisp(kXmmHex);
  if (!NoDebug()) showcrashreports();
  /* OnlyRunOnFirstCpu(); */
  if ((colorize = cancolor())) {
    g_high.keyword = 155;
    g_high.reg = 215;
    g_high.literal = 182;
    g_high.label = 221;
    g_high.comment = 112;
    g_high.quote = 215;
  }
  GetOpts(argc, argv);
  if (optind == argc) PrintUsage(EX_USAGE, stderr);
  return Emulator(argc, argv);
}