diff options
Diffstat (limited to 'lib/pure/math.nim')
-rw-r--r-- | lib/pure/math.nim | 88 |
1 files changed, 45 insertions, 43 deletions
diff --git a/lib/pure/math.nim b/lib/pure/math.nim index 4bc720a46..ed7d2382f 100644 --- a/lib/pure/math.nim +++ b/lib/pure/math.nim @@ -57,13 +57,14 @@ import std/private/since {.push debugger: off.} # the user does not want to trace a part # of the standard library! -import bitops, fenv +import std/[bitops, fenv] +import system/countbits_impl when defined(nimPreviewSlimSystem): import std/assertions -when defined(c) or defined(cpp): +when not defined(js) and not defined(nimscript): # C proc c_isnan(x: float): bool {.importc: "isnan", header: "<math.h>".} # a generic like `x: SomeFloat` might work too if this is implemented via a C macro. @@ -155,7 +156,7 @@ func fac*(n: int): int = {.push checks: off, line_dir: off, stack_trace: off.} -when defined(posix) and not defined(genode): +when defined(posix) and not defined(genode) and not defined(macosx): {.passl: "-lm".} const @@ -200,7 +201,7 @@ func isNaN*(x: SomeFloat): bool {.inline, since: (1,5,1).} = template fn: untyped = result = x != x when nimvm: fn() else: - when defined(js): fn() + when defined(js) or defined(nimscript): fn() else: result = c_isnan(x) when defined(js): @@ -219,13 +220,13 @@ when defined(js): let a = newFloat64Array(buffer) let b = newUint32Array(buffer) a[0] = x - asm """ + {.emit: """ function updateBit(num, bitPos, bitVal) { return (num & ~(1 << bitPos)) | (bitVal << bitPos); } `b`[1] = updateBit(`b`[1], 31, `sgn`); - `result` = `a`[0] - """ + `result` = `a`[0]; + """.} proc signbit*(x: SomeFloat): bool {.inline, since: (1, 5, 1).} = ## Returns true if `x` is negative, false otherwise. @@ -270,7 +271,6 @@ func classify*(x: float): FloatClass = ## Classifies a floating point value. ## ## Returns `x`'s class as specified by the `FloatClass enum<#FloatClass>`_. - ## Doesn't work with `--passc:-ffast-math`. runnableExamples: doAssert classify(0.3) == fcNormal doAssert classify(0.0) == fcZero @@ -279,6 +279,7 @@ func classify*(x: float): FloatClass = doAssert classify(5.0e-324) == fcSubnormal # JavaScript and most C compilers have no classify: + if isNan(x): return fcNan if x == 0.0: if 1.0 / x == Inf: return fcZero @@ -287,7 +288,6 @@ func classify*(x: float): FloatClass = if x * 0.5 == x: if x > 0.0: return fcInf else: return fcNegInf - if x != x: return fcNan if abs(x) < MinFloatNormal: return fcSubnormal return fcNormal @@ -1230,40 +1230,42 @@ func gcd*[T](x, y: T): T = swap x, y abs x -func gcd*(x, y: SomeInteger): SomeInteger = - ## Computes the greatest common (positive) divisor of `x` and `y`, - ## using the binary GCD (aka Stein's) algorithm. - ## - ## **See also:** - ## * `gcd func <#gcd,T,T>`_ for a float version - ## * `lcm func <#lcm,T,T>`_ - runnableExamples: - doAssert gcd(12, 8) == 4 - doAssert gcd(17, 63) == 1 - - when x is SomeSignedInt: - var x = abs(x) - else: - var x = x - when y is SomeSignedInt: - var y = abs(y) - else: - var y = y - - if x == 0: - return y - if y == 0: - return x - - let shift = countTrailingZeroBits(x or y) - y = y shr countTrailingZeroBits(y) - while x != 0: - x = x shr countTrailingZeroBits(x) - if y > x: - swap y, x - x -= y - y shl shift - +when useBuiltins: + ## this func uses bitwise comparisons from C compilers, which are not always available. + func gcd*(x, y: SomeInteger): SomeInteger = + ## Computes the greatest common (positive) divisor of `x` and `y`, + ## using the binary GCD (aka Stein's) algorithm. + ## + ## **See also:** + ## * `gcd func <#gcd,T,T>`_ for a float version + ## * `lcm func <#lcm,T,T>`_ + runnableExamples: + doAssert gcd(12, 8) == 4 + doAssert gcd(17, 63) == 1 + + when x is SomeSignedInt: + var x = abs(x) + else: + var x = x + when y is SomeSignedInt: + var y = abs(y) + else: + var y = y + + if x == 0: + return y + if y == 0: + return x + + let shift = countTrailingZeroBits(x or y) + y = y shr countTrailingZeroBits(y) + while x != 0: + x = x shr countTrailingZeroBits(x) + if y > x: + swap y, x + x -= y + y shl shift + func gcd*[T](x: openArray[T]): T {.since: (1, 1).} = ## Computes the greatest common (positive) divisor of the elements of `x`. ## |