1 files changed, 105 insertions, 0 deletions
diff --git a/_tests/perf.zig b/_tests/perf.zig
new file mode 100644
index 0000000..02c9226
--- /dev/null
+++ b/_tests/perf.zig
@@ -0,0 +1,105 @@
+const builtin = @import("builtin");
+const std = @import("std");
+
+const endian = builtin.target.cpu.arch.endian();
+
+const min = std.math.minInt(i52) + 1;
+const max = std.math.maxInt(i52) - 1;
+
+export fn checkValidRange(int: i64) u8 {
+    return if (min < int and int < max) 1 else 0;
+}
+
+export fn checkValidRange2(int: i64) u8 {
+    const x: u64 = @bitCast(int);
+    return if (if (int < 0)
+        x >> 51 == std.math.maxInt(u13)
+    else
+        x >> 51 == 0) 1 else 0;
+}
+
+export fn isFixnum(v: u64) u8 {
+    const expt = v >> 52;
+    const rest = v << 13;
+    return if (expt == 0xfff and rest != 0) 1 else 0;
+}
+
+export fn isFixnum2(v: u64) u8 {
+    const hi: u14 = @intCast(v >> 50);
+    return if (hi == (0xfff << 2 | 0b01)) 1 else 0;
+}
+
+export fn sstrLen(x: u64) u8 {
+    const bytes: @Vector(8, u8) = @bitCast(x);
+    const nulls: @Vector(8, u8) = @splat(0);
+    const comps: u8 = @bitCast(bytes == nulls);
+    // Two bits will always be 0, since the actual short string starts at the
+    // third byte; third lowest or third highest depending on endianness.  So,
+    // depending on endianness, either cut off the two leading bits and ensure
+    // that the second-last is set, or ensure that the second highest set, to
+    // limit the length to 6.
+    return switch (endian) {
+        .big => @clz(comps << 2 | 2),
+        .little => @ctz(comps | 64),
+    };
+}
+
+const positive_mask: u64 = 0xfff7ffffffffffff;
+
+fn unpackNegative(v: u64) i64 {
+    return @bitCast(v);
+}
+
+fn unpackPositive(v: u64) i64 {
+    const uint: u64 = @bitCast(v);
+    return @bitCast(uint ^ positive_mask);
+}
+
+fn packNegative(int: i64) u64 {
+    return @bitCast(int);
+}
+
+fn packPositive(int: i64) u64 {
+    const uint: u64 = @bitCast(int);
+    return @bitCast(uint ^ positive_mask);
+}
+
+export fn packFx(int: i64) u64 {
+    if (int < 0) {
+        return packNegative(int);
+    } else {
+        return packPositive(int);
+    }
+}
+
+export fn packSstr(len: usize, s: [*]const u8) u64 {
+    var v: u64 = 0xfff3000000000000;
+    const buf: *[8]u8 = @ptrCast(&v);
+    @memcpy(buf[0 .. 0 + len], s);
+    return v;
+}
+
+pub fn packSstrTest(buf: [*]const u64, len: usize) ?Value {
+    if (len > 6) return null;
+
+    const v = switch (endian) {
+        .big => @byteSwap(buf[0]),
+        .little => buf[0],
+    };
+
+    const shift: u6 = 8 * @as(u6, @intCast(len));
+    const mask = @as(u64, std.math.maxInt(u64)) << shift;
+    const s = Value{ .sstr = .{ .bytes = @intCast(v & ~mask) } };
+
+    // This effectively checks if there were any NUL bytes:
+    if (len != value.sstrLen(&s)) return null;
+
+    return s;
+}
+
+pub fn packSstrStatic(comptime s: []const u8) Value {
+    var val: u64 = undefined;
+    const buf: [*]align(8) u8 = @ptrCast(&val);
+    @memcpy(buf, s);
+    return pack(@ptrCast(buf), s.len).?;
+}