diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/pure/math.nim | 27 |
1 files changed, 26 insertions, 1 deletions
diff --git a/lib/pure/math.nim b/lib/pure/math.nim index a6a3676b9..bcda68afe 100644 --- a/lib/pure/math.nim +++ b/lib/pure/math.nim @@ -56,7 +56,7 @@ 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] when defined(c) or defined(cpp): proc c_isnan(x: float): bool {.importc: "isnan", header: "<math.h>".} @@ -65,6 +65,8 @@ when defined(c) or defined(cpp): proc c_copysign(x, y: cfloat): cfloat {.importc: "copysignf", header: "<math.h>".} proc c_copysign(x, y: cdouble): cdouble {.importc: "copysign", header: "<math.h>".} + proc c_signbit(x: SomeFloat): cint {.importc: "signbit", header: "<math.h>".} + func binom*(n, k: int): int = ## Computes the `binomial coefficient <https://en.wikipedia.org/wiki/Binomial_coefficient>`_. runnableExamples: @@ -156,6 +158,29 @@ func isNaN*(x: SomeFloat): bool {.inline, since: (1,5,1).} = when defined(js): fn() else: result = c_isnan(x) +when defined(js): + proc toBitsImpl(x: float): array[2, uint32] = + asm """ + const buffer = new ArrayBuffer(8); + const floatBuffer = new Float64Array(buffer); + const uintBuffer = new Uint32Array(buffer); + floatBuffer[0] = `x`; + `result` = uintBuffer + """ + +proc signbit*(x: SomeFloat): bool {.inline, since: (1, 5, 1).} = + ## Returns true if `x` is negative, false otherwise. + runnableExamples: + doAssert not signbit(0.0) + doAssert signbit(-0.0) + doAssert signbit(-0.1) + doAssert not signbit(0.1) + when defined(js): + let uintBuffer = toBitsImpl(x) + result = (uintBuffer[1] shr 31) != 0 + else: + result = c_signbit(x) != 0 + func copySign*[T: SomeFloat](x, y: T): T {.inline, since: (1, 5, 1).} = ## Returns a value with the magnitude of `x` and the sign of `y`; ## this works even if x or y are NaN or zero, both of which can carry a sign. |