As per GingerBill's request, copied the files over to a linux-specific file instead of renaming to .

core/runtime/internal_windows.odin

@@ -0,0 +1,135 @@
+package runtime
+
+@(link_name="__umodti3")
+umodti3 :: proc "c" (a, b: u128) -> u128 {
+    r: u128 = ---;
+    _ = udivmod128(a, b, &r);
+    return r;
+}
+
+
+@(link_name="__udivmodti4")
+udivmodti4 :: proc "c" (a, b: u128, rem: ^u128) -> u128 {
+    return udivmod128(a, b, rem);
+}
+
+@(link_name="__udivti3")
+udivti3 :: proc "c" (a, b: u128) -> u128 {
+    return udivmodti4(a, b, nil);
+}
+
+
+@(link_name="__modti3")
+modti3 :: proc "c" (a, b: i128) -> i128 {
+    s_a := a >> (128 - 1);
+    s_b := b >> (128 - 1);
+    an := (a ~ s_a) - s_a;
+    bn := (b ~ s_b) - s_b;
+
+    r: u128 = ---;
+    _ = udivmod128(transmute(u128)an, transmute(u128)bn, &r);
+    return (transmute(i128)r ~ s_a) - s_a;
+}
+
+
+@(link_name="__divmodti4")
+divmodti4 :: proc "c" (a, b: i128, rem: ^i128) -> i128 {
+    u := udivmod128(transmute(u128)a, transmute(u128)b, cast(^u128)rem);
+    return transmute(i128)u;
+}
+
+@(link_name="__divti3")
+divti3 :: proc "c" (a, b: i128) -> i128 {
+    u := udivmodti4(transmute(u128)a, transmute(u128)b, nil);
+    return transmute(i128)u;
+}
+
+
+@(link_name="__fixdfti")
+fixdfti :: proc(a: u64) -> i128 {
+    significandBits :: 52;
+    typeWidth       :: (size_of(u64)*8);
+    exponentBits    :: (typeWidth - significandBits - 1);
+    maxExponent     :: ((1 << exponentBits) - 1);
+    exponentBias    :: (maxExponent >> 1);
+
+    implicitBit     :: (u64(1) << significandBits);
+    significandMask :: (implicitBit - 1);
+    signBit         :: (u64(1) << (significandBits + exponentBits));
+    absMask         :: (signBit - 1);
+    exponentMask    :: (absMask ~ significandMask);
+
+    // Break a into sign, exponent, significand
+    aRep := a;
+    aAbs := aRep & absMask;
+    sign := i128(-1 if aRep & signBit != 0 else 1);
+    exponent := u64((aAbs >> significandBits) - exponentBias);
+    significand := u64((aAbs & significandMask) | implicitBit);
+
+    // If exponent is negative, the result is zero.
+    if exponent < 0 {
+        return 0;
+    }
+
+    // If the value is too large for the integer type, saturate.
+    if exponent >= size_of(i128) * 8 {
+        return max(i128) if sign == 1 else min(i128);
+    }
+
+    // If 0 <= exponent < significandBits, right shift to get the result.
+    // Otherwise, shift left.
+    if exponent < significandBits {
+        return sign * i128(significand >> (significandBits - exponent));
+    } else {
+        return sign * (i128(significand) << (exponent - significandBits));
+    }
+
+}
+
+@(default_calling_convention = "none")
+foreign {
+    @(link_name="llvm.ctlz.i128") _clz_i128 :: proc(x: i128, is_zero_undef := false) -> i128 ---
+}
+
+
+@(link_name="__floattidf")
+floattidf :: proc(a: i128) -> f64 {
+    DBL_MANT_DIG :: 53;
+    if a == 0 {
+        return 0.0;
+    }
+    a := a;
+    N :: size_of(i128) * 8;
+    s := a >> (N-1);
+    a = (a ~ s) - s;
+    sd: = N - _clz_i128(a);  // number of significant digits
+    e := u32(sd - 1);        // exponent 
+    if sd > DBL_MANT_DIG {
+        switch sd {
+        case DBL_MANT_DIG + 1:
+            a <<= 1;
+        case DBL_MANT_DIG + 2:
+            // okay
+        case:
+            a = i128(u128(a) >> u128(sd - (DBL_MANT_DIG+2))) |
+                i128(u128(a) & (~u128(0) >> u128(N + DBL_MANT_DIG+2 - sd)) != 0);
+        };
+
+        a |= i128((a & 4) != 0);  
+        a += 1; 
+        a >>= 2;
+
+        if a & (1 << DBL_MANT_DIG) != 0 {
+            a >>= 1;
+            e += 1;
+        }
+    } else {
+        a <<= u128(DBL_MANT_DIG - sd);
+    }
+    fb: [2]u32;
+    fb[1] = (u32(s) & 0x80000000) |        // sign
+            ((e + 1023) << 20)      |      // exponent
+            ((u32(a) >> 32) & 0x000FFFFF); // mantissa-high
+    fb[1] = u32(a);                        // mantissa-low
+    return transmute(f64)fb;
+}