From 0f0e4d15f7e23102ebb374504322942e3771357e Mon Sep 17 00:00:00 2001 From: daurnimator Date: Wed, 26 Apr 2017 23:48:06 +1000 Subject: Move frexp and ldexp to luaconf.js --- src/lobject.js | 28 +--------------------------- src/lstrlib.js | 2 +- src/luaconf.js | 25 +++++++++++++++++++++++++ 3 files changed, 27 insertions(+), 28 deletions(-) (limited to 'src') diff --git a/src/lobject.js b/src/lobject.js index f02f8f3..e785e68 100644 --- a/src/lobject.js +++ b/src/lobject.js @@ -277,30 +277,6 @@ const luaO_utf8desc = function(buff, x) { even with single floats) */ const MAXSIGDIG = 30; -// See: http://croquetweak.blogspot.fr/2014/08/deconstructing-floats-frexp-and-ldexp.html -const frexp = function(value) { - if (value === 0) return [value, 0]; - var data = new DataView(new ArrayBuffer(8)); - data.setFloat64(0, value); - var bits = (data.getUint32(0) >>> 20) & 0x7FF; - if (bits === 0) { // denormal - data.setFloat64(0, value * Math.pow(2, 64)); // exp + 64 - bits = ((data.getUint32(0) >>> 20) & 0x7FF) - 64; - } - var exponent = bits - 1022; - var mantissa = ldexp(value, -exponent); - return [mantissa, exponent]; -}; - -const ldexp = function(mantissa, exponent) { - var steps = Math.min(3, Math.ceil(Math.abs(exponent) / 1023)); - var result = mantissa; - for (var i = 0; i < steps; i++) - result *= Math.pow(2, Math.floor((exponent + i) / steps)); - return result; -}; - - /* ** convert an hexadecimal numeric string to a number, following ** C99 specification for 'strtod' @@ -354,7 +330,7 @@ const lua_strx2number = function(s) { e += exp1; } if (neg) r = -r; - return defs.to_jsstring(s).trim().search(/s/) < 0 ? ldexp(r, e) : null; /* Only valid if nothing left is s*/ + return defs.to_jsstring(s).trim().search(/s/) < 0 ? luaconf.ldexp(r, e) : null; /* Only valid if nothing left is s*/ }; const l_str2dloc = function(s, mode) { @@ -506,9 +482,7 @@ module.exports.LClosure = LClosure; module.exports.LocVar = LocVar; module.exports.TValue = TValue; module.exports.UTF8BUFFSZ = UTF8BUFFSZ; -module.exports.frexp = frexp; module.exports.intarith = intarith; -module.exports.ldexp = ldexp; module.exports.luaO_chunkid = luaO_chunkid; module.exports.luaO_hexavalue = luaO_hexavalue; module.exports.luaO_int2fb = luaO_int2fb; diff --git a/src/lstrlib.js b/src/lstrlib.js index 5bd08d4..f6353a0 100644 --- a/src/lstrlib.js +++ b/src/lstrlib.js @@ -111,7 +111,7 @@ const num2straux = function(x) { return ['-'.charCodeAt(0)].concat(zero); return zero; } else { - let fe = lobject.frexp(x); /* 'x' fraction and exponent */ + let fe = luaconf.frexp(x); /* 'x' fraction and exponent */ let m = fe[0]; let e = fe[1]; let n = 0; /* character count */ diff --git a/src/luaconf.js b/src/luaconf.js index 803bb90..7cf3d06 100644 --- a/src/luaconf.js +++ b/src/luaconf.js @@ -32,6 +32,31 @@ const lua_getlocaledecpoint = function() { return (1.1).toLocaleString().substring(1, 2); }; +// See: http://croquetweak.blogspot.fr/2014/08/deconstructing-floats-frexp-and-ldexp.html +const frexp = function(value) { + if (value === 0) return [value, 0]; + var data = new DataView(new ArrayBuffer(8)); + data.setFloat64(0, value); + var bits = (data.getUint32(0) >>> 20) & 0x7FF; + if (bits === 0) { // denormal + data.setFloat64(0, value * Math.pow(2, 64)); // exp + 64 + bits = ((data.getUint32(0) >>> 20) & 0x7FF) - 64; + } + var exponent = bits - 1022; + var mantissa = ldexp(value, -exponent); + return [mantissa, exponent]; +}; + +const ldexp = function(mantissa, exponent) { + var steps = Math.min(3, Math.ceil(Math.abs(exponent) / 1023)); + var result = mantissa; + for (var i = 0; i < steps; i++) + result *= Math.pow(2, Math.floor((exponent + i) / steps)); + return result; +}; + +module.exports.frexp = frexp; +module.exports.ldexp = ldexp; module.exports.LUAI_MAXSTACK = LUAI_MAXSTACK; module.exports.LUA_IDSIZE = LUA_IDSIZE; module.exports.LUA_INTEGER_FMT = LUA_INTEGER_FMT; -- cgit v1.2.3-54-g00ecf