RDTSC.reds

Red/System []

int64!: alias struct! [
    low     [integer!]
    high    [integer!]
]

sub64: func [
    a       [int64!]
    b       [int64!]
    return: [integer!]
][
    ;-- mov edx, [ebp + 8]
    ;-- mov ecx, [ebp + 12]
    ;-- mov eax, [edx]
    ;-- mov edx, [edx + 4]
    ;-- sub eax, [ecx]
    ;-- sbb edx, [ecx + 4]
    #inline [
        #{8B55088B4D0C8B028B52042B011B5104}
        return: [integer!]
    ]
]

rdtsc: func [n [int64!]][
    ;-- rdtsc
    ;-- cdq
    ;-- mov     ecx, DWORD PTR [ebp+8]
    ;-- mov     DWORD PTR [ecx], eax
    ;-- mov     DWORD PTR [ecx+4], edx
    #inline #{0F31998B4D088901895104}
]

test: func [
    /local
        f  [float!]
        n  [integer!]
        t1 [int64! value]
        t2 [int64! value]
][
    rdtsc :t1
    n: 0
    loop 10000000 [n: n + 1]
    rdtsc :t2
    probe [sub64 :t2 :t1]

    rdtsc :t1
    f: 0.0
    loop 10000000 [f: f + 1.0]
    rdtsc :t2
    probe [sub64 :t2 :t1]
]

test