From d76b9ffb3e6ed2d54367d7242134d3432ebb181e Mon Sep 17 00:00:00 2001
From: Francois Perrad <francois.perrad@gadz.org>
Date: Wed, 18 Dec 2019 10:17:56 +0100
Subject: [PATCH] library math integer

---
 Makefile              |  2 +-
 src/compat53/math.lua | 57 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 58 insertions(+), 1 deletion(-)
 create mode 100644 src/compat53/math.lua

diff --git a/Makefile b/Makefile
index 00c7d46e8c..4c3058db44 100644
--- a/Makefile
+++ b/Makefile
@@ -90,7 +90,7 @@ FILES_JITLIB= bc.lua bcsave.lua dump.lua p.lua v.lua zone.lua \
 	      dis_x86.lua dis_x64.lua dis_arm.lua dis_arm64.lua \
 	      dis_arm64be.lua dis_ppc.lua dis_mips.lua dis_mipsel.lua \
 	      dis_mips64.lua dis_mips64el.lua vmdef.lua
-FILES_COMPAT53= utf8.lua
+FILES_COMPAT53= math.lua utf8.lua
 FILES_COMPAT54= utf8.lua
 
 ifeq (,$(findstring Windows,$(OS)))
diff --git a/src/compat53/math.lua b/src/compat53/math.lua
new file mode 100644
index 0000000000..7e34fb8373
--- /dev/null
+++ b/src/compat53/math.lua
@@ -0,0 +1,57 @@
+----------------------------------------------------------------------------
+-- math integer library.
+--
+-- Copyright (C) 2019 Francois Perrad
+--
+-- This library is licensed under the terms of the MIT/X11 license,
+-- like LuaJIT itself.
+----------------------------------------------------------------------------
+
+local error, type = error, type
+local math = math
+
+math.maxinteger = 9007199254740992      -- 2^53
+math.mininteger = -9007199254740992
+
+function math.tointeger (n)
+  if type(n) == 'number' and n <= 9007199254740992 and n >= -9007199254740992 and n % 1 == 0 then
+    return n
+  end
+  return nil
+end
+
+function math.type (n)
+  if type(n) == 'number' then
+    if n <= 9007199254740992 and n >= -9007199254740992 and n % 1 == 0 then
+      return 'integer'
+    else
+      return 'float'
+    end
+  else
+    return nil
+  end
+end
+
+function math.ult (m, n)
+  local t = type(m)
+  if t ~= 'number' then
+    error("bad argument #1 to 'ult' (number expected, got " .. t .. ")", 2)
+  end
+  if m > 9007199254740992 or m < -9007199254740992 or m % 1 ~= 0 then
+    error("bad argument #1 to 'ult' (number has no integer representation)", 2)
+  end
+  t = type(n)
+  if t ~= 'number' then
+    error("bad argument #2 to 'ult' (number expected, got " .. t .. ")", 2)
+  end
+  if n > 9007199254740992 or n < -9007199254740992 or n % 1 ~= 0 then
+    error("bad argument #2 to 'ult' (number has no integer representation)", 2)
+  end
+  if m >= 0 and n < 0 then
+    return true
+  elseif m < 0 and n >= 0 then
+    return false
+  else
+    return m < n
+  end
+end