authorgravatar for jan.hafer@rwth-aachen.deJan Philipp Hafer <jan.hafer@rwth-aachen.de> 2021-09-07 23:20:13+02:00
committergravatar for andrew@ziglang.orgAndrew Kelley <andrew@ziglang.org> 2021-12-11 01:43:37-08:00
logefdb94486b78fa143f8d684609cb4c5d3de10124
tree23aa9a69b88c421ac03e94f1e6184a99abaeac50
parent97c0373fa7ee125d2d4e73f9b1dc8ea0e2c2e86a

compiler_rt: add __bswapsi2, __bswapdi2 and __bswapti2

- each byte gets masked, shifted and combined - use boring masks instead of comptime for readability - tests: bit patterns with reverse operation, if applicable See #1290

6 files changed, 148 insertions(+), 0 deletions(-)

CMakeLists.txt+1
......@@ -446,6 +446,7 @@ set(ZIG_STAGE2_SOURCES
446446 "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt.zig"
447447 "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/addXf3.zig"
448448 "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/atomics.zig"
449 "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/bswap.zig"
449450 "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/clear_cache.zig"
450451 "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/compareXf2.zig"
451452 "${CMAKE_SOURCE_DIR}/lib/std/special/compiler_rt/count0bits.zig"
lib/std/special/compiler_rt.zig+6
......@@ -263,6 +263,12 @@ comptime {
263263 @export(__popcountdi2, .{ .name = "__popcountdi2", .linkage = linkage });
264264 const __popcountti2 = @import("compiler_rt/popcount.zig").__popcountti2;
265265 @export(__popcountti2, .{ .name = "__popcountti2", .linkage = linkage });
266 const __bswapsi2 = @import("compiler_rt/bswap.zig").__bswapsi2;
267 @export(__bswapsi2, .{ .name = "__bswapsi2", .linkage = linkage });
268 const __bswapdi2 = @import("compiler_rt/bswap.zig").__bswapdi2;
269 @export(__bswapdi2, .{ .name = "__bswapdi2", .linkage = linkage });
270 const __bswapti2 = @import("compiler_rt/bswap.zig").__bswapti2;
271 @export(__bswapti2, .{ .name = "__bswapti2", .linkage = linkage });
266272
267273 // Integral / floating point conversion (part 1/2)
268274 const __floatsidf = @import("compiler_rt/floatsiXf.zig").__floatsidf;
lib/std/special/compiler_rt/bswap.zig created+78
......@@ -0,0 +1,78 @@
1const std = @import("std");
2const builtin = @import("builtin");
3
4// bswap - byteswap
5// - bswapXi2_generic for unoptimized big and little endian
6// ie for u32
7// DE AD BE EF <- little|big endian
8// FE BE AD DE <- big|little endian
9// ie for u32
10// ff 00 00 00 >> 3*8 (leftmost byte)
11// 00 ff 00 00 >> 1*8 (2nd left byte)
12// 00 00 ff 00 << 1*8 (2n right byte)
13// 00 00 00 ff << 3*8 (rightmost byte)
14
15fn bswapXi2_generic(comptime T: type) fn (a: T) callconv(.C) T {
16 return struct {
17 fn f(a: T) callconv(.C) T {
18 @setRuntimeSafety(builtin.is_test);
19 switch (@bitSizeOf(T)) {
20 32 => {
21 // zig fmt: off
22 return (((a & 0xff000000) >> 24)
23 | ((a & 0x00ff0000) >> 8 )
24 | ((a & 0x0000ff00) << 8 )
25 | ((a & 0x000000ff) << 24));
26 // zig fmt: on
27 },
28 64 => {
29 // zig fmt: off
30 return (((a & 0xff00000000000000) >> 56)
31 | ((a & 0x00ff000000000000) >> 40 )
32 | ((a & 0x0000ff0000000000) >> 24 )
33 | ((a & 0x000000ff00000000) >> 8 )
34 | ((a & 0x00000000ff000000) << 8 )
35 | ((a & 0x0000000000ff0000) << 24 )
36 | ((a & 0x000000000000ff00) << 40 )
37 | ((a & 0x00000000000000ff) << 56));
38 // zig fmt: on
39 },
40 128 => {
41 // zig fmt: off
42 return (((a & 0xff000000000000000000000000000000) >> 120)
43 | ((a & 0x00ff0000000000000000000000000000) >> 104)
44 | ((a & 0x0000ff00000000000000000000000000) >> 88 )
45 | ((a & 0x000000ff000000000000000000000000) >> 72 )
46 | ((a & 0x00000000ff0000000000000000000000) >> 56 )
47 | ((a & 0x0000000000ff00000000000000000000) >> 40 )
48 | ((a & 0x000000000000ff000000000000000000) >> 24 )
49 | ((a & 0x00000000000000ff0000000000000000) >> 8 )
50 | ((a & 0x0000000000000000ff00000000000000) << 8 )
51 | ((a & 0x000000000000000000ff000000000000) << 24 )
52 | ((a & 0x00000000000000000000ff0000000000) << 40 )
53 | ((a & 0x0000000000000000000000ff00000000) << 56 )
54 | ((a & 0x000000000000000000000000ff000000) << 72 )
55 | ((a & 0x00000000000000000000000000ff0000) << 88 )
56 | ((a & 0x0000000000000000000000000000ff00) << 104)
57 | ((a & 0x000000000000000000000000000000ff) << 120));
58 // zig fmt: on
59 },
60 else => {
61 unreachable;
62 },
63 }
64 }
65 }.f;
66}
67
68pub const __bswapsi2 = bswapXi2_generic(u32);
69
70pub const __bswapdi2 = bswapXi2_generic(u64);
71
72pub const __bswapti2 = bswapXi2_generic(u128);
73
74test {
75 _ = @import("bswapsi2_test.zig");
76 _ = @import("bswapdi2_test.zig");
77 _ = @import("bswapti2_test.zig");
78}
lib/std/special/compiler_rt/bswapdi2_test.zig created+21
......@@ -0,0 +1,21 @@
1const bswap = @import("bswap.zig");
2const testing = @import("std").testing;
3
4fn test__bswapdi2(a: u64, expected: u64) !void {
5 var result = bswap.__bswapdi2(a);
6 try testing.expectEqual(expected, result);
7}
8
9test "bswapdi2" {
10 try test__bswapdi2(0x0123456789abcdef, 0xefcdab8967452301); // 0..f
11 try test__bswapdi2(0xefcdab8967452301, 0x0123456789abcdef);
12 try test__bswapdi2(0x89abcdef01234567, 0x67452301efcdab89); // 8..f0..7
13 try test__bswapdi2(0x67452301efcdab89, 0x89abcdef01234567);
14 try test__bswapdi2(0xdeadbeefdeadbeef, 0xefbeaddeefbeadde); // deadbeefdeadbeef
15 try test__bswapdi2(0xefbeaddeefbeadde, 0xdeadbeefdeadbeef);
16 try test__bswapdi2(0xdeadfacedeadface, 0xcefaaddecefaadde); // deadfacedeadface
17 try test__bswapdi2(0xcefaaddecefaadde, 0xdeadfacedeadface);
18 try test__bswapdi2(0xaaaaaaaaaaaaaaaa, 0xaaaaaaaaaaaaaaaa); // uninitialized memory
19 try test__bswapdi2(0x0000000000000000, 0x0000000000000000); // 0s
20 try test__bswapdi2(0xffffffffffffffff, 0xffffffffffffffff); // fs
21}
lib/std/special/compiler_rt/bswapsi2_test.zig created+21
......@@ -0,0 +1,21 @@
1const bswap = @import("bswap.zig");
2const testing = @import("std").testing;
3
4fn test__bswapsi2(a: u32, expected: u32) !void {
5 var result = bswap.__bswapsi2(a);
6 try testing.expectEqual(expected, result);
7}
8
9test "bswapsi2" {
10 try test__bswapsi2(0x01234567, 0x67452301); // 0..7
11 try test__bswapsi2(0x67452301, 0x01234567);
12 try test__bswapsi2(0x89abcdef, 0xefcdab89); // 8..f
13 try test__bswapsi2(0xefcdab89, 0x89abcdef);
14 try test__bswapsi2(0xdeadbeef, 0xefbeadde); // deadbeef
15 try test__bswapsi2(0xefbeadde, 0xdeadbeef);
16 try test__bswapsi2(0xdeadface, 0xcefaadde); // deadface
17 try test__bswapsi2(0xcefaadde, 0xdeadface);
18 try test__bswapsi2(0xaaaaaaaa, 0xaaaaaaaa); // uninitialized memory
19 try test__bswapsi2(0x00000000, 0x00000000); // 0s
20 try test__bswapsi2(0xffffffff, 0xffffffff); // fs
21}
lib/std/special/compiler_rt/bswapti2_test.zig created+21
......@@ -0,0 +1,21 @@
1const bswap = @import("bswap.zig");
2const testing = @import("std").testing;
3
4fn test__bswapti2(a: u128, expected: u128) !void {
5 var result = bswap.__bswapti2(a);
6 try testing.expectEqual(expected, result);
7}
8
9test "bswapti2" {
10 try test__bswapti2(0x0123456789abcdef0123456789abcdef, 0xefcdab8967452301efcdab8967452301); // 0..f
11 try test__bswapti2(0xefcdab8967452301efcdab8967452301, 0x0123456789abcdef0123456789abcdef);
12 try test__bswapti2(0x89abcdef0123456789abcdef01234567, 0x67452301efcdab8967452301efcdab89); // 8..f0..7
13 try test__bswapti2(0x67452301efcdab8967452301efcdab89, 0x89abcdef0123456789abcdef01234567);
14 try test__bswapti2(0xdeadbeefdeadbeefdeadbeefdeadbeef, 0xefbeaddeefbeaddeefbeaddeefbeadde); // deadbeefdeadbeef
15 try test__bswapti2(0xefbeaddeefbeaddeefbeaddeefbeadde, 0xdeadbeefdeadbeefdeadbeefdeadbeef);
16 try test__bswapti2(0xdeadfacedeadfacedeadfacedeadface, 0xcefaaddecefaaddecefaaddecefaadde); // deadfacedeadface
17 try test__bswapti2(0xcefaaddecefaaddecefaaddecefaadde, 0xdeadfacedeadfacedeadfacedeadface);
18 try test__bswapti2(0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa, 0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa); // uninitialized memory
19 try test__bswapti2(0x00000000000000000000000000000000, 0x00000000000000000000000000000000); // 0s
20 try test__bswapti2(0xffffffffffffffffffffffffffffffff, 0xffffffffffffffffffffffffffffffff); // fs
21}