//===--- FloatingPoint.swift.gyb ------------------------------*- swift -*-===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See http://swift.org/LICENSE.txt for license information
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//

%{
#
# Utility code for later in this template
#

# // Bit counts for all floating point types. 
# // 80-bit floating point types are only permitted on x86 architectures. This
# // restriction is handled via #if's in the generated code.
allFloatBits = [32, 64, 80]

# Bit counts for all int types
allIntBits = [8, 16, 32, 64, 'Int']

# Number of bits in integer literals.
builtinIntLiteralBits = 2048

def allInts():
    for bits in allIntBits:
        for signed in False, True:
            yield bits,signed

def baseIntName(name):
    return 'Int' if name == 'Int' else 'Int' + str(name)

def builtinIntName(name):
    return 'Word' if name == 'Int' else 'Int' + str(name)

def intName(name, signed):
    return ('' if signed else 'U') + baseIntName(name)

def floatName(bits):
    if bits == 32:
        return 'Float'
    if bits == 64:
        return 'Double'
    if bits == 80:
        return 'Float80'

def cFuncSuffix(bits):
    if bits == 32:
        return 'f'
    if bits == 64:
        return ''
    if bits == 80:
        return 'l'

def llvmIntrinsicSuffix(bits):
    if bits == 32:
        return 'f32'
    if bits == 64:
        return 'f64'
    if bits == 80:
        return 'f80'

def getInfBitPattern(bits):
    if bits == 32:
        return '0x7f800000'
    if bits == 64:
        return '0x7ff0000000000000'
    return 'error'

def getQuietNaNBitPattern(bits):
    if bits == 32:
        return '0x7fc00000'
    if bits == 64:
        return '0x7ff8000000000000'
    return 'error'

def getSignalingNanBitPattern(bits):
    if bits == 32:
        return '0x7fa00000'
    if bits == 64:
        return '0x7ff4000000000000'
    return 'error'

def getMinNormalBitPattern(bits):
    if bits == 32:
        return '0x00800000'
    if bits == 64:
        return '0x0010000000000000'
    return 'error'

def getExponentBitCount(bits):
    if bits == 32:
        return '8'
    if bits == 64:
        return '11'
    return 'error'

def getSignificantBitCount(bits):
    if bits == 32:
        return '23'
    if bits == 64:
        return '52'
    return 'error'

def getInfinityExponent(bits):
    if bits == 32:
        return '0xff'
    if bits == 64:
        return '0x7ff'
    return 'error'

}%

% for bits in allFloatBits:
%   Self = floatName(bits)

% if bits == 80:
#if arch(i386) || arch(x86_64)
% end

public struct ${Self} {
  var value: Builtin.FPIEEE${bits}

  /// Create an instance initialized to zero.
  @transparent public
  init() {
    var zero: Int64 = 0
    value = Builtin.uitofp_Int64_FPIEEE${bits}(zero.value)
  }

  @transparent 
  public // @testable
  init(_bits v: Builtin.FPIEEE${bits}) {
    value = v
  }

  /// Create an instance initialized to `value`.
  @transparent public
  init(_ value: ${Self}) { self = value }
}

extension ${Self} : Printable {
  /// A textual representation of `self`.
  public var description: String {
    return _float${bits}ToString(self)
  }
}

% if bits in allIntBits:
// Not transparent because the compiler crashes in that case.
//@transparent
extension ${Self} : FloatingPointType {
  public typealias _BitsType = UInt${bits}

  public static func _fromBitPattern(bits: _BitsType) -> ${Self} {
    return ${Self}(_bits: Builtin.bitcast_Int${bits}_FPIEEE${bits}(bits.value))
  }

  public func _toBitPattern() -> _BitsType {
    return _BitsType(Builtin.bitcast_FPIEEE${bits}_Int${bits}(value))
  }

  func __getSignBit() -> Int {
    return Int(_toBitPattern() >> ${bits - 1}) & 1
  }

  func __getBiasedExponent() -> _BitsType {
    return (_toBitPattern() >> ${getSignificantBitCount(bits)}) & ${getInfinityExponent(bits)}
  }

  func __getSignificand() -> _BitsType {
    var mask: _BitsType = (1 << ${getSignificantBitCount(bits)}) - 1
    return _toBitPattern() & mask
  }

  /// The positive infinity.
  public static var infinity: ${Self} {
    return _fromBitPattern(${getInfBitPattern(bits)})
  }

  /// A quiet NaN.
  public static var NaN: ${Self} {
    return quietNaN
  }

  /// A quiet NaN.
  public static var quietNaN: ${Self} {
    return _fromBitPattern(${getQuietNaNBitPattern(bits)})
  }

  /// `true` iff `self` is negative
  public var isSignMinus: Bool {
    return __getSignBit() == 1
  }

  /// `true` iff `self` is normal (not zero, subnormal, infinity, or
  /// NaN).
  public var isNormal:  Bool {
    var biasedExponent = __getBiasedExponent()
    return biasedExponent != ${getInfinityExponent(bits)} &&
           biasedExponent != 0
  }

  /// `true` iff `self` is zero, subnormal, or normal (not infinity
  /// or NaN).
  public var isFinite:  Bool {
    return __getBiasedExponent() != ${getInfinityExponent(bits)}
  }

  /// `true` iff `self` is +0.0 or -0.0.
  public var isZero:  Bool {
    // Mask out the sign bit.
    var mask: _BitsType = (1 << (${bits} - 1)) - 1
    return (_toBitPattern() & mask) == 0
  }

  /// `true` iff `self` is subnormal.
  public var isSubnormal:  Bool {
    if __getBiasedExponent() == 0 {
      return __getSignificand() != 0
    }
    return false

    // Alternative implementation:
    // return !isNan() &&
    //     abs(self) < ${Self}._fromBitPattern(${getMinNormalBitPattern(bits)})
    //
    // But because we need to check for !isNan(), and do it safely in case of
    // SNaN, we need to go down to the bit level, so open-coding the combined
    // condition is going to be faster.
  }

  /// `true` iff `self` is infinity.
  public var isInfinite:  Bool {
    if __getBiasedExponent() == ${getInfinityExponent(bits)} {
      return __getSignificand() == 0
    }
    return false

    // Alternative implementation that is not safe in case of SNaN:
    // return abs(self) == ${Self}.infinity()
  }

  /// `true` iff `self` is NaN.
  public var isNaN:  Bool {
    if __getBiasedExponent() == ${getInfinityExponent(bits)} {
      return __getSignificand() != 0
    }
    return false

    // Alternative implementation that is not safe in case of SNaN:
    // return self != self
  }

  /// `true` iff `self` is a signaling NaN.
  public var isSignaling: Bool {
    if __getBiasedExponent() == ${getInfinityExponent(bits)} {
      // IEEE-754R 2008 6.2.1: A signaling NaN bit string should be encoded
      // with the first bit of the trailing significand being 0.  If the first
      // bit of the trailing significand field is 0, some other bit of the
      // trailing significand field must be non-zero to distinguish the NaN
      // from infinity.
      var significand = __getSignificand()
      if significand != 0 {
        return (significand >> (${getSignificantBitCount(bits)} - 1)) == 0
      }
    }
    return false
  }
}

// Not @transparent because the function is too complex.
extension ${Self} /* : FloatingPointType */ {
  /// The IEEE 754 "class" of this type.
  public var floatingPointClass: FloatingPointClassification {
    get {
      var biasedExponent = __getBiasedExponent()
      if biasedExponent == ${getInfinityExponent(bits)} {
        var significand = __getSignificand()
        // This is either +/-inf or NaN.
        if significand == 0 {
          return isSignMinus ? .NegativeInfinity : .PositiveInfinity
        }
        var isQNaN = (significand >> (${getSignificantBitCount(bits)} - 1)) == 1
        return isQNaN ? .QuietNaN : .SignalingNaN
      }

      // OK, the number is finite.
      var isMinus = isSignMinus
      if biasedExponent != 0 {
        return isMinus ? .NegativeNormal : .PositiveNormal
      }

      // Exponent is zero.
      if __getSignificand() == 0 {
        return isMinus ? .NegativeZero : .PositiveZero
      }
      return isMinus ? .NegativeSubnormal : .PositiveSubnormal
    }
  }
}
% end

@transparent
extension ${Self} : _BuiltinIntegerLiteralConvertible, IntegerLiteralConvertible {
  public
  init(_builtinIntegerLiteral value: Builtin.Int${builtinIntLiteralBits}){
    self = ${Self}(_bits: Builtin.itofp_with_overflow_Int${builtinIntLiteralBits}_FPIEEE${bits}(value))
  }

  /// Create an instance initialized to `value`.
  public init(integerLiteral value: Int64) {
    self = ${Self}(_bits: Builtin.uitofp_Int64_FPIEEE${bits}(value.value))
  }
}

#if arch(i386) || arch(x86_64)

% builtinFloatLiteralBits = 80
@transparent
extension ${Self} : _BuiltinFloatLiteralConvertible {
  public
  init(_builtinFloatLiteral value: Builtin.FPIEEE${builtinFloatLiteralBits}) {
%   if bits == builtinFloatLiteralBits:
    self = ${Self}(_bits: value)
%   elif bits < builtinFloatLiteralBits:
    self = ${Self}(_bits: Builtin.fptrunc_FPIEEE${builtinFloatLiteralBits}_FPIEEE${bits}(value))
%   else:
    // FIXME: This is actually losing precision <rdar://problem/14073102>.
    self = ${Self}(Builtin.fpext_FPIEEE${builtinFloatLiteralBits}_FPIEEE${bits}(value))
%   end
  }
}

#else

% builtinFloatLiteralBits = 64
@transparent
extension ${Self} : _BuiltinFloatLiteralConvertible {
  public
  init(_builtinFloatLiteral value: Builtin.FPIEEE${builtinFloatLiteralBits}) {
%   if bits == builtinFloatLiteralBits:
    self = ${Self}(_bits: value)
%   elif bits < builtinFloatLiteralBits:
    self = ${Self}(_bits: Builtin.fptrunc_FPIEEE${builtinFloatLiteralBits}_FPIEEE${bits}(value))
%   else:
    // FIXME: This is actually losing precision <rdar://problem/14073102>.
    self = ${Self}(Builtin.fpext_FPIEEE${builtinFloatLiteralBits}_FPIEEE${bits}(value))
%   end
  }
}

#endif

@transparent
extension ${Self} : FloatLiteralConvertible {
  /// Create an instance initialized to `value`.
  public init(floatLiteral value: ${Self}) {
    self = value
  }
}

@transparent
public func ==(lhs: ${Self}, rhs: ${Self}) -> Bool {
  return Bool(Builtin.fcmp_oeq_FPIEEE${bits}(lhs.value, rhs.value))
}

@transparent
public func <(lhs: ${Self}, rhs: ${Self}) -> Bool {
  return Bool(Builtin.fcmp_olt_FPIEEE${bits}(lhs.value, rhs.value))
}

@transparent
extension ${Self} : Comparable {
}

extension ${Self} : Hashable {
  /// The hash value.
  ///
  /// **Axiom:** `x == y` implies `x.hashValue == y.hashValue`
  ///
  /// **Note:** the hash value is not guaranteed to be stable across
  /// different invocations of the same program.  Do not persist the
  /// hash value across program runs.
  public var hashValue: Int {
    var asBuiltinInt = Builtin.bitcast_FPIEEE${bits}_Int${bits}(value)
%   if bits >= 64:
    return Int(Builtin.truncOrBitCast_Int${bits}_Word(asBuiltinInt))
%   elif bits <= 32:
    return Int(Builtin.sextOrBitCast_Int${bits}_Word(asBuiltinInt))
%   else:
    error unhandled float size ${bits}
%   end
  }
}

@transparent
extension ${Self} : AbsoluteValuable {
  /// Returns the absolute value of `x`
  @transparent
  public static func abs(x: ${Self}) -> ${Self} {
    return ${Self}(_bits: Builtin.int_fabs_FPIEEE${bits}(x.value))
  }
}

@transparent
public prefix func +(x: ${Self}) -> ${Self} {
  return x
}

@transparent
public prefix func -(x: ${Self}) -> ${Self} {
  return ${Self}(_bits: Builtin.fneg_FPIEEE${bits}(x.value))
}

//===----------------------------------------------------------------------===//
// Explicit conversions between types.
//===----------------------------------------------------------------------===//

// Construction from integers.
@transparent
extension ${Self} {
% for (srcBits, srcSigned) in allInts():
%    That = intName(srcBits, srcSigned)
%    ThatBuiltinName = builtinIntName(srcBits)
%    sign = 's' if srcSigned else 'u'
  public init(_ v: ${That}) {
    value = Builtin.${sign}itofp_${ThatBuiltinName}_FPIEEE${bits}(v.value)
  }
% end
}

// Construction from other floating point numbers.
@transparent
extension ${Self} {
% for srcBits in allFloatBits:
%   That = floatName(srcBits)
%   if Self != That:

%     if srcBits == 80:
#if arch(i386) || arch(x86_64)
%     end

  /// Construct an instance that approximates `other`.
  public init(_ other: ${That}) {
%     if srcBits > bits:
    value = Builtin.fptrunc_FPIEEE${srcBits}_FPIEEE${bits}(other.value)
%     else:
    value = Builtin.fpext_FPIEEE${srcBits}_FPIEEE${bits}(other.value)
%     end
  }

%     if srcBits == 80:
#endif
%     end

%   end
% end
}

//===----------------------------------------------------------------------===//
// Standard Operator Table
//===----------------------------------------------------------------------===//

@transparent
public prefix func ++ (inout rhs: ${Self}) -> ${Self} { rhs += 1.0; return rhs }
@transparent
public prefix func -- (inout rhs: ${Self}) -> ${Self} { rhs -= 1.0; return rhs }
@transparent
public postfix func ++ (inout lhs: ${Self}) -> ${Self} { let tmp = lhs; lhs += 1.0; return tmp }
@transparent
public postfix func -- (inout lhs: ${Self}) -> ${Self} { let tmp = lhs; lhs -= 1.0; return tmp }



@transparent
extension ${Self} : Strideable {
  /// Returns a stride `x` such that `self.advancedBy(x)` approximates
  /// `other`.
  ///
  /// Complexity: O(1).
  @transparent public
  func distanceTo(other: ${Self}) -> ${Self} {
    return other - self
  }
  
  /// Returns a `Self` `x` such that `self.distanceTo(x)` approximates
  /// `n`.
  ///
  /// Complexity: O(1).
  @transparent public
  func advancedBy(amount: ${Self}) -> ${Self} {
    return self + amount
  }
}

% for op, name in ('+','fadd'), ('-','fsub'),('*','fmul'), ('/','fdiv'):
@transparent
public func ${op} (lhs: ${Self}, rhs: ${Self}) -> ${Self} {
  return ${Self}(_bits: Builtin.${name}_FPIEEE${bits}(lhs.value, rhs.value))
}
% end

// Binary Remainder.
// The sign of the result matches the sign of the dividend.
// 1) This is consistent with '%' in C#, D, Java, and JavaScript
// 2) C99 requires this behavior for fmod*()
// 3) C++11 requires this behavior for std::fmod*()
@asmname("_swift_fmod${cFuncSuffix(bits)}") public
func % (lhs: ${Self}, rhs: ${Self}) -> ${Self}

// See Bool.swift for && and ||
// In C, 120 is &&
// In C, 110 is ||

// In C, 100 is ?:
// In C, 90 is =, *=, += etc.

% for op in '+', '-', '*', '/', '%':
@transparent
public func ${op}= (inout lhs: ${Self}, rhs: ${Self}) { lhs = lhs ${op} rhs }
% end

% if bits == 80:
#endif
% end

% end # for bits in allFloatBits

// Construction of integers from floating point numbers.
% for (bits, signed) in allInts():
%   sign = 's' if signed else 'u'
%   Self = intName(bits, signed)
%   BuiltinName = builtinIntName(bits)
@transparent
extension ${Self} {
%   for srcBits in allFloatBits:
%     That = floatName(srcBits)

%     if srcBits == 80:
#if arch(i386) || arch(x86_64)
%     end

  /// Construct an instance that approximates `other`.
  public init(_ other: ${That}) {
%     if srcBits != 80:
    // FIXME: Float80 does not have 'isFinite' property.
    // <rdar://problem/17958458> Int(Float80.quietNaN) is garbage
    // <rdar://problem/17959546> Float80.isFinite is missing
    _precondition(
      other.isFinite,
      "floating point value can not be converted to ${Self} because it is either infinite or NaN")
%     end
    _precondition(other >= ${That}(${Self}.min),
        "floating point value can not be converted to ${Self} because it is less than ${Self}.min")
    _precondition(other <= ${That}(${Self}.max),
        "floating point value can not be converted to ${Self} because it is greater than ${Self}.max")
    value = Builtin.fpto${sign}i_FPIEEE${srcBits}_${BuiltinName}(other.value)
  }

%      if srcBits == 80:
#endif
%       end

%   end
}

% end

// ${'Local Variables'}:
// eval: (read-only-mode 1)
// End: