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Diffstat (limited to 'src/root.zig')
| -rw-r--r-- | src/root.zig | 191 |
1 files changed, 0 insertions, 191 deletions
diff --git a/src/root.zig b/src/root.zig deleted file mode 100644 index 05ad381..0000000 --- a/src/root.zig +++ /dev/null @@ -1,191 +0,0 @@ -//! By convention, root.zig is the root source file when making a library. If -//! you are making an executable, the convention is to delete this file and -//! start with main.zig instead. -const std = @import("std"); -const builtin = @import("builtin"); -const testing = std.testing; - -// Read the following article to understand the NaN-packing strategy: -// -// https://tkammer.de/zisp/notes/nan.html -// -// Note: Packed structs are least-to-most significant, so the order of fields -// must be reversed relative to a typical big-endian illustration of the bit -// patterns of IEEE 754 double-precision floating point numbers. - -const Value = packed union { - double: f64, - nan: packed struct { - rest: u51, - quiet: u1, - exp: u11, - sign: u1, - }, - int: packed struct { - code: u51, - neg: bool, - exp: u11, - is_int: bool, - }, - pointer: packed struct { - value: u48, - type: u3, - _zo: u1, - _qnan: u12, - }, -}; - -// Helpers - -inline fn zisp_dump(v: Value) void { - std.debug.dumpHex(std.mem.asBytes(&v)); -} - -///! Checks for any IEEE 754 NaN. -inline fn zisp_is_nan(v: Value) bool { - return v.nan.exp == std.math.maxInt(u11); -} - -///! Checks for a Zisp value packed into a NaN. -inline fn zisp_is_packed(v: Value) bool { - return zisp_is_nan(v) and v.nan.rest != 0; -} - -///! Checks for a regular double including infinity or canonical NaN -inline fn zisp_is_double(v: Value) bool { - return !zisp_is_packed(v); -} - -inline fn zisp_assert_double(v: Value) void { - if (!zisp_is_double(v)) { - zisp_dump(v); - @panic("not double"); - } -} - -inline fn zisp_is_int(v: Value) bool { - return zisp_is_packed(v) and v.int.is_int; -} - -inline fn zisp_assert_int(v: Value) void { - if (!zisp_is_int(v)) { - zisp_dump(v); - @panic("not int"); - } -} - -// See detailed NaN packing docs for why the +/- 1. -const zisp_int_min = std.math.minInt(i52) + 1; -const zisp_int_max = std.math.maxInt(i52) - 1; - -inline fn zisp_assert_int_range(int: i64) void { - if (int < zisp_int_min) { - std.debug.print("int to pack is too small: {}", .{int}); - @panic("int to pack is too small"); - } - if (int > zisp_int_max) { - std.debug.print("int to pack is too large: {}", .{int}); - @panic("int to pack is too large"); - } -} - -inline fn zisp_int_pack_neg(int: i64) Value { - return @bitCast(int); -} - -inline fn zisp_int_unpack_neg(v: Value) i64 { - return @bitCast(v); -} - -const zisp_int_pos_mask: u64 = 0xfff7ffffffffffff; - -inline fn zisp_int_pack_pos(int: i64) Value { - const uint: u64 = @bitCast(int); - return @bitCast(uint ^ zisp_int_pos_mask); -} - -inline fn zisp_int_unpack_pos(v: Value) i64 { - const uint: u64 = @bitCast(v); - return @bitCast(uint ^ zisp_int_pos_mask); -} - -inline fn zisp_int_pack(int: i64) Value { - zisp_assert_int_range(int); - if (int < 0) { - return zisp_int_pack_neg(int); - } else { - return zisp_int_pack_pos(int); - } -} - -inline fn zisp_int_unpack(v: Value) i64 { - zisp_assert_int(v); - if (v.int.neg) { - return zisp_int_unpack_neg(v); - } else { - return zisp_int_unpack_pos(v); - } -} - -// Doubles - -pub fn zisp_double(d: f64) Value { - return @bitCast(d); -} - -// pub fn zisp_double_p(v: Value) Value { -// return zisp_bool(zisp_is_double(v)); -// } - -pub fn zisp_double_get(v: Value) f64 { - zisp_assert_double(v); - return v.double; -} - -pub fn zisp_double_add(v1: Value, v2: Value) Value { - const d1 = zisp_double_get(v1); - const d2 = zisp_double_get(v2); - return zisp_double(d1 + d2); -} - -// Ints - -pub fn zisp_int(int: i64) Value { - return zisp_int_pack(int); -} - -// pub fn zisp_int_p(v: Value) Value { -// return zisp_bool(zisp_is_int(v)); -// } - -pub fn zisp_int_get(v: Value) i64 { - return zisp_int_unpack(v); -} - -pub fn zisp_int_add(v1: Value, v2: Value) Value { - const int1 = zisp_int_get(v1); - const int2 = zisp_int_get(v2); - return zisp_int(int1 + int2); -} - -// Tests - -test "double add functionality" { - const d1: f64 = 0.123456789; - const d2: f64 = -0.987654321; - const v1 = zisp_double(d1); - const v2 = zisp_double(d2); - const v3 = zisp_double_add(v1, v2); - const result = zisp_double_get(v3); - try std.testing.expect(result == d1 + d2); -} - -test "int add functionality" { - const int1: i64 = 123456789; - const int2: i64 = -987654321; - const v1 = zisp_int(int1); - const v2 = zisp_int(int2); - const v3 = zisp_int_add(v1, v2); - const result = zisp_int_get(v3); - try std.testing.expect(result == int1 + int2); -} |