From ccd992355df7192993c666236047820244914598 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Tue, 16 Apr 2024 21:19:13 +0200 Subject: Adding upstream version 1.21.8. Signed-off-by: Daniel Baumann --- src/math/bits/bits_test.go | 1347 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 1347 insertions(+) create mode 100644 src/math/bits/bits_test.go (limited to 'src/math/bits/bits_test.go') diff --git a/src/math/bits/bits_test.go b/src/math/bits/bits_test.go new file mode 100644 index 0000000..23b4539 --- /dev/null +++ b/src/math/bits/bits_test.go @@ -0,0 +1,1347 @@ +// Copyright 2017 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package bits_test + +import ( + . "math/bits" + "runtime" + "testing" + "unsafe" +) + +func TestUintSize(t *testing.T) { + var x uint + if want := unsafe.Sizeof(x) * 8; UintSize != want { + t.Fatalf("UintSize = %d; want %d", UintSize, want) + } +} + +func TestLeadingZeros(t *testing.T) { + for i := 0; i < 256; i++ { + nlz := tab[i].nlz + for k := 0; k < 64-8; k++ { + x := uint64(i) << uint(k) + if x <= 1<<8-1 { + got := LeadingZeros8(uint8(x)) + want := nlz - k + (8 - 8) + if x == 0 { + want = 8 + } + if got != want { + t.Fatalf("LeadingZeros8(%#02x) == %d; want %d", x, got, want) + } + } + + if x <= 1<<16-1 { + got := LeadingZeros16(uint16(x)) + want := nlz - k + (16 - 8) + if x == 0 { + want = 16 + } + if got != want { + t.Fatalf("LeadingZeros16(%#04x) == %d; want %d", x, got, want) + } + } + + if x <= 1<<32-1 { + got := LeadingZeros32(uint32(x)) + want := nlz - k + (32 - 8) + if x == 0 { + want = 32 + } + if got != want { + t.Fatalf("LeadingZeros32(%#08x) == %d; want %d", x, got, want) + } + if UintSize == 32 { + got = LeadingZeros(uint(x)) + if got != want { + t.Fatalf("LeadingZeros(%#08x) == %d; want %d", x, got, want) + } + } + } + + if x <= 1<<64-1 { + got := LeadingZeros64(uint64(x)) + want := nlz - k + (64 - 8) + if x == 0 { + want = 64 + } + if got != want { + t.Fatalf("LeadingZeros64(%#016x) == %d; want %d", x, got, want) + } + if UintSize == 64 { + got = LeadingZeros(uint(x)) + if got != want { + t.Fatalf("LeadingZeros(%#016x) == %d; want %d", x, got, want) + } + } + } + } + } +} + +// Exported (global) variable serving as input for some +// of the benchmarks to ensure side-effect free calls +// are not optimized away. +var Input uint64 = DeBruijn64 + +// Exported (global) variable to store function results +// during benchmarking to ensure side-effect free calls +// are not optimized away. +var Output int + +func BenchmarkLeadingZeros(b *testing.B) { + var s int + for i := 0; i < b.N; i++ { + s += LeadingZeros(uint(Input) >> (uint(i) % UintSize)) + } + Output = s +} + +func BenchmarkLeadingZeros8(b *testing.B) { + var s int + for i := 0; i < b.N; i++ { + s += LeadingZeros8(uint8(Input) >> (uint(i) % 8)) + } + Output = s +} + +func BenchmarkLeadingZeros16(b *testing.B) { + var s int + for i := 0; i < b.N; i++ { + s += LeadingZeros16(uint16(Input) >> (uint(i) % 16)) + } + Output = s +} + +func BenchmarkLeadingZeros32(b *testing.B) { + var s int + for i := 0; i < b.N; i++ { + s += LeadingZeros32(uint32(Input) >> (uint(i) % 32)) + } + Output = s +} + +func BenchmarkLeadingZeros64(b *testing.B) { + var s int + for i := 0; i < b.N; i++ { + s += LeadingZeros64(uint64(Input) >> (uint(i) % 64)) + } + Output = s +} + +func TestTrailingZeros(t *testing.T) { + for i := 0; i < 256; i++ { + ntz := tab[i].ntz + for k := 0; k < 64-8; k++ { + x := uint64(i) << uint(k) + want := ntz + k + if x <= 1<<8-1 { + got := TrailingZeros8(uint8(x)) + if x == 0 { + want = 8 + } + if got != want { + t.Fatalf("TrailingZeros8(%#02x) == %d; want %d", x, got, want) + } + } + + if x <= 1<<16-1 { + got := TrailingZeros16(uint16(x)) + if x == 0 { + want = 16 + } + if got != want { + t.Fatalf("TrailingZeros16(%#04x) == %d; want %d", x, got, want) + } + } + + if x <= 1<<32-1 { + got := TrailingZeros32(uint32(x)) + if x == 0 { + want = 32 + } + if got != want { + t.Fatalf("TrailingZeros32(%#08x) == %d; want %d", x, got, want) + } + if UintSize == 32 { + got = TrailingZeros(uint(x)) + if got != want { + t.Fatalf("TrailingZeros(%#08x) == %d; want %d", x, got, want) + } + } + } + + if x <= 1<<64-1 { + got := TrailingZeros64(uint64(x)) + if x == 0 { + want = 64 + } + if got != want { + t.Fatalf("TrailingZeros64(%#016x) == %d; want %d", x, got, want) + } + if UintSize == 64 { + got = TrailingZeros(uint(x)) + if got != want { + t.Fatalf("TrailingZeros(%#016x) == %d; want %d", x, got, want) + } + } + } + } + } +} + +func BenchmarkTrailingZeros(b *testing.B) { + var s int + for i := 0; i < b.N; i++ { + s += TrailingZeros(uint(Input) << (uint(i) % UintSize)) + } + Output = s +} + +func BenchmarkTrailingZeros8(b *testing.B) { + var s int + for i := 0; i < b.N; i++ { + s += TrailingZeros8(uint8(Input) << (uint(i) % 8)) + } + Output = s +} + +func BenchmarkTrailingZeros16(b *testing.B) { + var s int + for i := 0; i < b.N; i++ { + s += TrailingZeros16(uint16(Input) << (uint(i) % 16)) + } + Output = s +} + +func BenchmarkTrailingZeros32(b *testing.B) { + var s int + for i := 0; i < b.N; i++ { + s += TrailingZeros32(uint32(Input) << (uint(i) % 32)) + } + Output = s +} + +func BenchmarkTrailingZeros64(b *testing.B) { + var s int + for i := 0; i < b.N; i++ { + s += TrailingZeros64(uint64(Input) << (uint(i) % 64)) + } + Output = s +} + +func TestOnesCount(t *testing.T) { + var x uint64 + for i := 0; i <= 64; i++ { + testOnesCount(t, x, i) + x = x<<1 | 1 + } + + for i := 64; i >= 0; i-- { + testOnesCount(t, x, i) + x = x << 1 + } + + for i := 0; i < 256; i++ { + for k := 0; k < 64-8; k++ { + testOnesCount(t, uint64(i)<>(8-k&0x7) + if got8 != want8 { + t.Fatalf("RotateLeft8(%#02x, %d) == %#02x; want %#02x", x8, k, got8, want8) + } + got8 = RotateLeft8(want8, -int(k)) + if got8 != x8 { + t.Fatalf("RotateLeft8(%#02x, -%d) == %#02x; want %#02x", want8, k, got8, x8) + } + + x16 := uint16(m) + got16 := RotateLeft16(x16, int(k)) + want16 := x16<<(k&0xf) | x16>>(16-k&0xf) + if got16 != want16 { + t.Fatalf("RotateLeft16(%#04x, %d) == %#04x; want %#04x", x16, k, got16, want16) + } + got16 = RotateLeft16(want16, -int(k)) + if got16 != x16 { + t.Fatalf("RotateLeft16(%#04x, -%d) == %#04x; want %#04x", want16, k, got16, x16) + } + + x32 := uint32(m) + got32 := RotateLeft32(x32, int(k)) + want32 := x32<<(k&0x1f) | x32>>(32-k&0x1f) + if got32 != want32 { + t.Fatalf("RotateLeft32(%#08x, %d) == %#08x; want %#08x", x32, k, got32, want32) + } + got32 = RotateLeft32(want32, -int(k)) + if got32 != x32 { + t.Fatalf("RotateLeft32(%#08x, -%d) == %#08x; want %#08x", want32, k, got32, x32) + } + if UintSize == 32 { + x := uint(m) + got := RotateLeft(x, int(k)) + want := x<<(k&0x1f) | x>>(32-k&0x1f) + if got != want { + t.Fatalf("RotateLeft(%#08x, %d) == %#08x; want %#08x", x, k, got, want) + } + got = RotateLeft(want, -int(k)) + if got != x { + t.Fatalf("RotateLeft(%#08x, -%d) == %#08x; want %#08x", want, k, got, x) + } + } + + x64 := uint64(m) + got64 := RotateLeft64(x64, int(k)) + want64 := x64<<(k&0x3f) | x64>>(64-k&0x3f) + if got64 != want64 { + t.Fatalf("RotateLeft64(%#016x, %d) == %#016x; want %#016x", x64, k, got64, want64) + } + got64 = RotateLeft64(want64, -int(k)) + if got64 != x64 { + t.Fatalf("RotateLeft64(%#016x, -%d) == %#016x; want %#016x", want64, k, got64, x64) + } + if UintSize == 64 { + x := uint(m) + got := RotateLeft(x, int(k)) + want := x<<(k&0x3f) | x>>(64-k&0x3f) + if got != want { + t.Fatalf("RotateLeft(%#016x, %d) == %#016x; want %#016x", x, k, got, want) + } + got = RotateLeft(want, -int(k)) + if got != x { + t.Fatalf("RotateLeft(%#08x, -%d) == %#08x; want %#08x", want, k, got, x) + } + } + } +} + +func BenchmarkRotateLeft(b *testing.B) { + var s uint + for i := 0; i < b.N; i++ { + s += RotateLeft(uint(Input), i) + } + Output = int(s) +} + +func BenchmarkRotateLeft8(b *testing.B) { + var s uint8 + for i := 0; i < b.N; i++ { + s += RotateLeft8(uint8(Input), i) + } + Output = int(s) +} + +func BenchmarkRotateLeft16(b *testing.B) { + var s uint16 + for i := 0; i < b.N; i++ { + s += RotateLeft16(uint16(Input), i) + } + Output = int(s) +} + +func BenchmarkRotateLeft32(b *testing.B) { + var s uint32 + for i := 0; i < b.N; i++ { + s += RotateLeft32(uint32(Input), i) + } + Output = int(s) +} + +func BenchmarkRotateLeft64(b *testing.B) { + var s uint64 + for i := 0; i < b.N; i++ { + s += RotateLeft64(uint64(Input), i) + } + Output = int(s) +} + +func TestReverse(t *testing.T) { + // test each bit + for i := uint(0); i < 64; i++ { + testReverse(t, uint64(1)<> (64 - 8)) + if got8 != want8 { + t.Fatalf("Reverse8(%#02x) == %#02x; want %#02x", x8, got8, want8) + } + + x16 := uint16(x64) + got16 := Reverse16(x16) + want16 := uint16(want64 >> (64 - 16)) + if got16 != want16 { + t.Fatalf("Reverse16(%#04x) == %#04x; want %#04x", x16, got16, want16) + } + + x32 := uint32(x64) + got32 := Reverse32(x32) + want32 := uint32(want64 >> (64 - 32)) + if got32 != want32 { + t.Fatalf("Reverse32(%#08x) == %#08x; want %#08x", x32, got32, want32) + } + if UintSize == 32 { + x := uint(x32) + got := Reverse(x) + want := uint(want32) + if got != want { + t.Fatalf("Reverse(%#08x) == %#08x; want %#08x", x, got, want) + } + } + + got64 := Reverse64(x64) + if got64 != want64 { + t.Fatalf("Reverse64(%#016x) == %#016x; want %#016x", x64, got64, want64) + } + if UintSize == 64 { + x := uint(x64) + got := Reverse(x) + want := uint(want64) + if got != want { + t.Fatalf("Reverse(%#08x) == %#016x; want %#016x", x, got, want) + } + } +} + +func BenchmarkReverse(b *testing.B) { + var s uint + for i := 0; i < b.N; i++ { + s += Reverse(uint(i)) + } + Output = int(s) +} + +func BenchmarkReverse8(b *testing.B) { + var s uint8 + for i := 0; i < b.N; i++ { + s += Reverse8(uint8(i)) + } + Output = int(s) +} + +func BenchmarkReverse16(b *testing.B) { + var s uint16 + for i := 0; i < b.N; i++ { + s += Reverse16(uint16(i)) + } + Output = int(s) +} + +func BenchmarkReverse32(b *testing.B) { + var s uint32 + for i := 0; i < b.N; i++ { + s += Reverse32(uint32(i)) + } + Output = int(s) +} + +func BenchmarkReverse64(b *testing.B) { + var s uint64 + for i := 0; i < b.N; i++ { + s += Reverse64(uint64(i)) + } + Output = int(s) +} + +func TestReverseBytes(t *testing.T) { + for _, test := range []struct { + x, r uint64 + }{ + {0, 0}, + {0x01, 0x01 << 56}, + {0x0123, 0x2301 << 48}, + {0x012345, 0x452301 << 40}, + {0x01234567, 0x67452301 << 32}, + {0x0123456789, 0x8967452301 << 24}, + {0x0123456789ab, 0xab8967452301 << 16}, + {0x0123456789abcd, 0xcdab8967452301 << 8}, + {0x0123456789abcdef, 0xefcdab8967452301 << 0}, + } { + testReverseBytes(t, test.x, test.r) + testReverseBytes(t, test.r, test.x) + } +} + +func testReverseBytes(t *testing.T, x64, want64 uint64) { + x16 := uint16(x64) + got16 := ReverseBytes16(x16) + want16 := uint16(want64 >> (64 - 16)) + if got16 != want16 { + t.Fatalf("ReverseBytes16(%#04x) == %#04x; want %#04x", x16, got16, want16) + } + + x32 := uint32(x64) + got32 := ReverseBytes32(x32) + want32 := uint32(want64 >> (64 - 32)) + if got32 != want32 { + t.Fatalf("ReverseBytes32(%#08x) == %#08x; want %#08x", x32, got32, want32) + } + if UintSize == 32 { + x := uint(x32) + got := ReverseBytes(x) + want := uint(want32) + if got != want { + t.Fatalf("ReverseBytes(%#08x) == %#08x; want %#08x", x, got, want) + } + } + + got64 := ReverseBytes64(x64) + if got64 != want64 { + t.Fatalf("ReverseBytes64(%#016x) == %#016x; want %#016x", x64, got64, want64) + } + if UintSize == 64 { + x := uint(x64) + got := ReverseBytes(x) + want := uint(want64) + if got != want { + t.Fatalf("ReverseBytes(%#016x) == %#016x; want %#016x", x, got, want) + } + } +} + +func BenchmarkReverseBytes(b *testing.B) { + var s uint + for i := 0; i < b.N; i++ { + s += ReverseBytes(uint(i)) + } + Output = int(s) +} + +func BenchmarkReverseBytes16(b *testing.B) { + var s uint16 + for i := 0; i < b.N; i++ { + s += ReverseBytes16(uint16(i)) + } + Output = int(s) +} + +func BenchmarkReverseBytes32(b *testing.B) { + var s uint32 + for i := 0; i < b.N; i++ { + s += ReverseBytes32(uint32(i)) + } + Output = int(s) +} + +func BenchmarkReverseBytes64(b *testing.B) { + var s uint64 + for i := 0; i < b.N; i++ { + s += ReverseBytes64(uint64(i)) + } + Output = int(s) +} + +func TestLen(t *testing.T) { + for i := 0; i < 256; i++ { + len := 8 - tab[i].nlz + for k := 0; k < 64-8; k++ { + x := uint64(i) << uint(k) + want := 0 + if x != 0 { + want = len + k + } + if x <= 1<<8-1 { + got := Len8(uint8(x)) + if got != want { + t.Fatalf("Len8(%#02x) == %d; want %d", x, got, want) + } + } + + if x <= 1<<16-1 { + got := Len16(uint16(x)) + if got != want { + t.Fatalf("Len16(%#04x) == %d; want %d", x, got, want) + } + } + + if x <= 1<<32-1 { + got := Len32(uint32(x)) + if got != want { + t.Fatalf("Len32(%#08x) == %d; want %d", x, got, want) + } + if UintSize == 32 { + got := Len(uint(x)) + if got != want { + t.Fatalf("Len(%#08x) == %d; want %d", x, got, want) + } + } + } + + if x <= 1<<64-1 { + got := Len64(uint64(x)) + if got != want { + t.Fatalf("Len64(%#016x) == %d; want %d", x, got, want) + } + if UintSize == 64 { + got := Len(uint(x)) + if got != want { + t.Fatalf("Len(%#016x) == %d; want %d", x, got, want) + } + } + } + } + } +} + +const ( + _M = 1< 0 { + panic("overflow") + } + return x + }, + func(a, b uint64) uint64 { + x, c := Add64(a, b, 0) + if c != 0 { + panic("overflow") + } + return x + }, + func(a, b uint64) uint64 { + x, c := Add64(a, b, 0) + if c == 1 { + panic("overflow") + } + return x + }, + func(a, b uint64) uint64 { + x, c := Add64(a, b, 0) + if c != 1 { + return x + } + panic("overflow") + }, + func(a, b uint64) uint64 { + x, c := Add64(a, b, 0) + if c == 0 { + return x + } + panic("overflow") + }, + } + for _, test := range tests { + shouldPanic := func(f func()) { + defer func() { + if err := recover(); err == nil { + t.Fatalf("expected panic") + } + }() + f() + } + + // overflow + shouldPanic(func() { test(_M64, 1) }) + shouldPanic(func() { test(1, _M64) }) + shouldPanic(func() { test(_M64, _M64) }) + + // no overflow + test(_M64, 0) + test(0, 0) + test(1, 1) + } +} + +func TestSub64OverflowPanic(t *testing.T) { + // Test that 64-bit overflow panics fire correctly. + // These are designed to improve coverage of compiler intrinsics. + tests := []func(uint64, uint64) uint64{ + func(a, b uint64) uint64 { + x, c := Sub64(a, b, 0) + if c > 0 { + panic("overflow") + } + return x + }, + func(a, b uint64) uint64 { + x, c := Sub64(a, b, 0) + if c != 0 { + panic("overflow") + } + return x + }, + func(a, b uint64) uint64 { + x, c := Sub64(a, b, 0) + if c == 1 { + panic("overflow") + } + return x + }, + func(a, b uint64) uint64 { + x, c := Sub64(a, b, 0) + if c != 1 { + return x + } + panic("overflow") + }, + func(a, b uint64) uint64 { + x, c := Sub64(a, b, 0) + if c == 0 { + return x + } + panic("overflow") + }, + } + for _, test := range tests { + shouldPanic := func(f func()) { + defer func() { + if err := recover(); err == nil { + t.Fatalf("expected panic") + } + }() + f() + } + + // overflow + shouldPanic(func() { test(0, 1) }) + shouldPanic(func() { test(1, _M64) }) + shouldPanic(func() { test(_M64-1, _M64) }) + + // no overflow + test(_M64, 0) + test(0, 0) + test(1, 1) + } +} + +func TestMulDiv(t *testing.T) { + testMul := func(msg string, f func(x, y uint) (hi, lo uint), x, y, hi, lo uint) { + hi1, lo1 := f(x, y) + if hi1 != hi || lo1 != lo { + t.Errorf("%s: got hi:lo = %#x:%#x; want %#x:%#x", msg, hi1, lo1, hi, lo) + } + } + testDiv := func(msg string, f func(hi, lo, y uint) (q, r uint), hi, lo, y, q, r uint) { + q1, r1 := f(hi, lo, y) + if q1 != q || r1 != r { + t.Errorf("%s: got q:r = %#x:%#x; want %#x:%#x", msg, q1, r1, q, r) + } + } + for _, a := range []struct { + x, y uint + hi, lo, r uint + }{ + {1 << (UintSize - 1), 2, 1, 0, 1}, + {_M, _M, _M - 1, 1, 42}, + } { + testMul("Mul", Mul, a.x, a.y, a.hi, a.lo) + testMul("Mul symmetric", Mul, a.y, a.x, a.hi, a.lo) + testDiv("Div", Div, a.hi, a.lo+a.r, a.y, a.x, a.r) + testDiv("Div symmetric", Div, a.hi, a.lo+a.r, a.x, a.y, a.r) + // The above code can't test intrinsic implementation, because the passed function is not called directly. + // The following code uses a closure to test the intrinsic version in case the function is intrinsified. + testMul("Mul intrinsic", func(x, y uint) (uint, uint) { return Mul(x, y) }, a.x, a.y, a.hi, a.lo) + testMul("Mul intrinsic symmetric", func(x, y uint) (uint, uint) { return Mul(x, y) }, a.y, a.x, a.hi, a.lo) + testDiv("Div intrinsic", func(hi, lo, y uint) (uint, uint) { return Div(hi, lo, y) }, a.hi, a.lo+a.r, a.y, a.x, a.r) + testDiv("Div intrinsic symmetric", func(hi, lo, y uint) (uint, uint) { return Div(hi, lo, y) }, a.hi, a.lo+a.r, a.x, a.y, a.r) + } +} + +func TestMulDiv32(t *testing.T) { + testMul := func(msg string, f func(x, y uint32) (hi, lo uint32), x, y, hi, lo uint32) { + hi1, lo1 := f(x, y) + if hi1 != hi || lo1 != lo { + t.Errorf("%s: got hi:lo = %#x:%#x; want %#x:%#x", msg, hi1, lo1, hi, lo) + } + } + testDiv := func(msg string, f func(hi, lo, y uint32) (q, r uint32), hi, lo, y, q, r uint32) { + q1, r1 := f(hi, lo, y) + if q1 != q || r1 != r { + t.Errorf("%s: got q:r = %#x:%#x; want %#x:%#x", msg, q1, r1, q, r) + } + } + for _, a := range []struct { + x, y uint32 + hi, lo, r uint32 + }{ + {1 << 31, 2, 1, 0, 1}, + {0xc47dfa8c, 50911, 0x98a4, 0x998587f4, 13}, + {_M32, _M32, _M32 - 1, 1, 42}, + } { + testMul("Mul32", Mul32, a.x, a.y, a.hi, a.lo) + testMul("Mul32 symmetric", Mul32, a.y, a.x, a.hi, a.lo) + testDiv("Div32", Div32, a.hi, a.lo+a.r, a.y, a.x, a.r) + testDiv("Div32 symmetric", Div32, a.hi, a.lo+a.r, a.x, a.y, a.r) + } +} + +func TestMulDiv64(t *testing.T) { + testMul := func(msg string, f func(x, y uint64) (hi, lo uint64), x, y, hi, lo uint64) { + hi1, lo1 := f(x, y) + if hi1 != hi || lo1 != lo { + t.Errorf("%s: got hi:lo = %#x:%#x; want %#x:%#x", msg, hi1, lo1, hi, lo) + } + } + testDiv := func(msg string, f func(hi, lo, y uint64) (q, r uint64), hi, lo, y, q, r uint64) { + q1, r1 := f(hi, lo, y) + if q1 != q || r1 != r { + t.Errorf("%s: got q:r = %#x:%#x; want %#x:%#x", msg, q1, r1, q, r) + } + } + for _, a := range []struct { + x, y uint64 + hi, lo, r uint64 + }{ + {1 << 63, 2, 1, 0, 1}, + {0x3626229738a3b9, 0xd8988a9f1cc4a61, 0x2dd0712657fe8, 0x9dd6a3364c358319, 13}, + {_M64, _M64, _M64 - 1, 1, 42}, + } { + testMul("Mul64", Mul64, a.x, a.y, a.hi, a.lo) + testMul("Mul64 symmetric", Mul64, a.y, a.x, a.hi, a.lo) + testDiv("Div64", Div64, a.hi, a.lo+a.r, a.y, a.x, a.r) + testDiv("Div64 symmetric", Div64, a.hi, a.lo+a.r, a.x, a.y, a.r) + // The above code can't test intrinsic implementation, because the passed function is not called directly. + // The following code uses a closure to test the intrinsic version in case the function is intrinsified. + testMul("Mul64 intrinsic", func(x, y uint64) (uint64, uint64) { return Mul64(x, y) }, a.x, a.y, a.hi, a.lo) + testMul("Mul64 intrinsic symmetric", func(x, y uint64) (uint64, uint64) { return Mul64(x, y) }, a.y, a.x, a.hi, a.lo) + testDiv("Div64 intrinsic", func(hi, lo, y uint64) (uint64, uint64) { return Div64(hi, lo, y) }, a.hi, a.lo+a.r, a.y, a.x, a.r) + testDiv("Div64 intrinsic symmetric", func(hi, lo, y uint64) (uint64, uint64) { return Div64(hi, lo, y) }, a.hi, a.lo+a.r, a.x, a.y, a.r) + } +} + +const ( + divZeroError = "runtime error: integer divide by zero" + overflowError = "runtime error: integer overflow" +) + +func TestDivPanicOverflow(t *testing.T) { + // Expect a panic + defer func() { + if err := recover(); err == nil { + t.Error("Div should have panicked when y<=hi") + } else if e, ok := err.(runtime.Error); !ok || e.Error() != overflowError { + t.Errorf("Div expected panic: %q, got: %q ", overflowError, e.Error()) + } + }() + q, r := Div(1, 0, 1) + t.Errorf("undefined q, r = %v, %v calculated when Div should have panicked", q, r) +} + +func TestDiv32PanicOverflow(t *testing.T) { + // Expect a panic + defer func() { + if err := recover(); err == nil { + t.Error("Div32 should have panicked when y<=hi") + } else if e, ok := err.(runtime.Error); !ok || e.Error() != overflowError { + t.Errorf("Div32 expected panic: %q, got: %q ", overflowError, e.Error()) + } + }() + q, r := Div32(1, 0, 1) + t.Errorf("undefined q, r = %v, %v calculated when Div32 should have panicked", q, r) +} + +func TestDiv64PanicOverflow(t *testing.T) { + // Expect a panic + defer func() { + if err := recover(); err == nil { + t.Error("Div64 should have panicked when y<=hi") + } else if e, ok := err.(runtime.Error); !ok || e.Error() != overflowError { + t.Errorf("Div64 expected panic: %q, got: %q ", overflowError, e.Error()) + } + }() + q, r := Div64(1, 0, 1) + t.Errorf("undefined q, r = %v, %v calculated when Div64 should have panicked", q, r) +} + +func TestDivPanicZero(t *testing.T) { + // Expect a panic + defer func() { + if err := recover(); err == nil { + t.Error("Div should have panicked when y==0") + } else if e, ok := err.(runtime.Error); !ok || e.Error() != divZeroError { + t.Errorf("Div expected panic: %q, got: %q ", divZeroError, e.Error()) + } + }() + q, r := Div(1, 1, 0) + t.Errorf("undefined q, r = %v, %v calculated when Div should have panicked", q, r) +} + +func TestDiv32PanicZero(t *testing.T) { + // Expect a panic + defer func() { + if err := recover(); err == nil { + t.Error("Div32 should have panicked when y==0") + } else if e, ok := err.(runtime.Error); !ok || e.Error() != divZeroError { + t.Errorf("Div32 expected panic: %q, got: %q ", divZeroError, e.Error()) + } + }() + q, r := Div32(1, 1, 0) + t.Errorf("undefined q, r = %v, %v calculated when Div32 should have panicked", q, r) +} + +func TestDiv64PanicZero(t *testing.T) { + // Expect a panic + defer func() { + if err := recover(); err == nil { + t.Error("Div64 should have panicked when y==0") + } else if e, ok := err.(runtime.Error); !ok || e.Error() != divZeroError { + t.Errorf("Div64 expected panic: %q, got: %q ", divZeroError, e.Error()) + } + }() + q, r := Div64(1, 1, 0) + t.Errorf("undefined q, r = %v, %v calculated when Div64 should have panicked", q, r) +} + +func TestRem32(t *testing.T) { + // Sanity check: for non-oveflowing dividends, the result is the + // same as the rem returned by Div32 + hi, lo, y := uint32(510510), uint32(9699690), uint32(510510+1) // ensure hi < y + for i := 0; i < 1000; i++ { + r := Rem32(hi, lo, y) + _, r2 := Div32(hi, lo, y) + if r != r2 { + t.Errorf("Rem32(%v, %v, %v) returned %v, but Div32 returned rem %v", hi, lo, y, r, r2) + } + y += 13 + } +} + +func TestRem32Overflow(t *testing.T) { + // To trigger a quotient overflow, we need y <= hi + hi, lo, y := uint32(510510), uint32(9699690), uint32(7) + for i := 0; i < 1000; i++ { + r := Rem32(hi, lo, y) + _, r2 := Div64(0, uint64(hi)<<32|uint64(lo), uint64(y)) + if r != uint32(r2) { + t.Errorf("Rem32(%v, %v, %v) returned %v, but Div64 returned rem %v", hi, lo, y, r, r2) + } + y += 13 + } +} + +func TestRem64(t *testing.T) { + // Sanity check: for non-oveflowing dividends, the result is the + // same as the rem returned by Div64 + hi, lo, y := uint64(510510), uint64(9699690), uint64(510510+1) // ensure hi < y + for i := 0; i < 1000; i++ { + r := Rem64(hi, lo, y) + _, r2 := Div64(hi, lo, y) + if r != r2 { + t.Errorf("Rem64(%v, %v, %v) returned %v, but Div64 returned rem %v", hi, lo, y, r, r2) + } + y += 13 + } +} + +func TestRem64Overflow(t *testing.T) { + Rem64Tests := []struct { + hi, lo, y uint64 + rem uint64 + }{ + // Testcases computed using Python 3, as: + // >>> hi = 42; lo = 1119; y = 42 + // >>> ((hi<<64)+lo) % y + {42, 1119, 42, 27}, + {42, 1119, 38, 9}, + {42, 1119, 26, 23}, + {469, 0, 467, 271}, + {469, 0, 113, 58}, + {111111, 111111, 1171, 803}, + {3968194946088682615, 3192705705065114702, 1000037, 56067}, + } + + for _, rt := range Rem64Tests { + if rt.hi < rt.y { + t.Fatalf("Rem64(%v, %v, %v) is not a test with quo overflow", rt.hi, rt.lo, rt.y) + } + rem := Rem64(rt.hi, rt.lo, rt.y) + if rem != rt.rem { + t.Errorf("Rem64(%v, %v, %v) returned %v, wanted %v", + rt.hi, rt.lo, rt.y, rem, rt.rem) + } + } +} + +func BenchmarkAdd(b *testing.B) { + var z, c uint + for i := 0; i < b.N; i++ { + z, c = Add(uint(Input), uint(i), c) + } + Output = int(z + c) +} + +func BenchmarkAdd32(b *testing.B) { + var z, c uint32 + for i := 0; i < b.N; i++ { + z, c = Add32(uint32(Input), uint32(i), c) + } + Output = int(z + c) +} + +func BenchmarkAdd64(b *testing.B) { + var z, c uint64 + for i := 0; i < b.N; i++ { + z, c = Add64(uint64(Input), uint64(i), c) + } + Output = int(z + c) +} + +func BenchmarkAdd64multiple(b *testing.B) { + var z0 = uint64(Input) + var z1 = uint64(Input) + var z2 = uint64(Input) + var z3 = uint64(Input) + for i := 0; i < b.N; i++ { + var c uint64 + z0, c = Add64(z0, uint64(i), c) + z1, c = Add64(z1, uint64(i), c) + z2, c = Add64(z2, uint64(i), c) + z3, _ = Add64(z3, uint64(i), c) + } + Output = int(z0 + z1 + z2 + z3) +} + +func BenchmarkSub(b *testing.B) { + var z, c uint + for i := 0; i < b.N; i++ { + z, c = Sub(uint(Input), uint(i), c) + } + Output = int(z + c) +} + +func BenchmarkSub32(b *testing.B) { + var z, c uint32 + for i := 0; i < b.N; i++ { + z, c = Sub32(uint32(Input), uint32(i), c) + } + Output = int(z + c) +} + +func BenchmarkSub64(b *testing.B) { + var z, c uint64 + for i := 0; i < b.N; i++ { + z, c = Sub64(uint64(Input), uint64(i), c) + } + Output = int(z + c) +} + +func BenchmarkSub64multiple(b *testing.B) { + var z0 = uint64(Input) + var z1 = uint64(Input) + var z2 = uint64(Input) + var z3 = uint64(Input) + for i := 0; i < b.N; i++ { + var c uint64 + z0, c = Sub64(z0, uint64(i), c) + z1, c = Sub64(z1, uint64(i), c) + z2, c = Sub64(z2, uint64(i), c) + z3, _ = Sub64(z3, uint64(i), c) + } + Output = int(z0 + z1 + z2 + z3) +} + +func BenchmarkMul(b *testing.B) { + var hi, lo uint + for i := 0; i < b.N; i++ { + hi, lo = Mul(uint(Input), uint(i)) + } + Output = int(hi + lo) +} + +func BenchmarkMul32(b *testing.B) { + var hi, lo uint32 + for i := 0; i < b.N; i++ { + hi, lo = Mul32(uint32(Input), uint32(i)) + } + Output = int(hi + lo) +} + +func BenchmarkMul64(b *testing.B) { + var hi, lo uint64 + for i := 0; i < b.N; i++ { + hi, lo = Mul64(uint64(Input), uint64(i)) + } + Output = int(hi + lo) +} + +func BenchmarkDiv(b *testing.B) { + var q, r uint + for i := 0; i < b.N; i++ { + q, r = Div(1, uint(i), uint(Input)) + } + Output = int(q + r) +} + +func BenchmarkDiv32(b *testing.B) { + var q, r uint32 + for i := 0; i < b.N; i++ { + q, r = Div32(1, uint32(i), uint32(Input)) + } + Output = int(q + r) +} + +func BenchmarkDiv64(b *testing.B) { + var q, r uint64 + for i := 0; i < b.N; i++ { + q, r = Div64(1, uint64(i), uint64(Input)) + } + Output = int(q + r) +} + +// ---------------------------------------------------------------------------- +// Testing support + +type entry = struct { + nlz, ntz, pop int +} + +// tab contains results for all uint8 values +var tab [256]entry + +func init() { + tab[0] = entry{8, 8, 0} + for i := 1; i < len(tab); i++ { + // nlz + x := i // x != 0 + n := 0 + for x&0x80 == 0 { + n++ + x <<= 1 + } + tab[i].nlz = n + + // ntz + x = i // x != 0 + n = 0 + for x&1 == 0 { + n++ + x >>= 1 + } + tab[i].ntz = n + + // pop + x = i // x != 0 + n = 0 + for x != 0 { + n += int(x & 1) + x >>= 1 + } + tab[i].pop = n + } +} -- cgit v1.2.3