flags_test.go

     1  // Copyright 2020 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build amd64 || arm64
     6  
     7  package ssa
     8  
     9  // This file tests the functions addFlags64 and subFlags64 by comparing their
    10  // results to what the chip calculates.
    11  
    12  import (
    13  	"runtime"
    14  	"testing"
    15  )
    16  
    17  func TestAddFlagsNative(t *testing.T) {
    18  	var numbers = []int64{
    19  		1, 0, -1,
    20  		2, -2,
    21  		1<<63 - 1, -1 << 63,
    22  	}
    23  	coverage := map[flagConstant]bool{}
    24  	for _, x := range numbers {
    25  		for _, y := range numbers {
    26  			a := addFlags64(x, y)
    27  			b := flagRegister2flagConstant(asmAddFlags(x, y), false)
    28  			if a != b {
    29  				t.Errorf("asmAdd diff: x=%x y=%x got=%s want=%s\n", x, y, a, b)
    30  			}
    31  			coverage[a] = true
    32  		}
    33  	}
    34  	if len(coverage) != 9 { // TODO: can we cover all outputs?
    35  		t.Errorf("coverage too small, got %d want 9", len(coverage))
    36  	}
    37  }
    38  
    39  func TestSubFlagsNative(t *testing.T) {
    40  	var numbers = []int64{
    41  		1, 0, -1,
    42  		2, -2,
    43  		1<<63 - 1, -1 << 63,
    44  	}
    45  	coverage := map[flagConstant]bool{}
    46  	for _, x := range numbers {
    47  		for _, y := range numbers {
    48  			a := subFlags64(x, y)
    49  			b := flagRegister2flagConstant(asmSubFlags(x, y), true)
    50  			if a != b {
    51  				t.Errorf("asmSub diff: x=%x y=%x got=%s want=%s\n", x, y, a, b)
    52  			}
    53  			coverage[a] = true
    54  		}
    55  	}
    56  	if len(coverage) != 7 { // TODO: can we cover all outputs?
    57  		t.Errorf("coverage too small, got %d want 7", len(coverage))
    58  	}
    59  }
    60  
    61  func TestAndFlagsNative(t *testing.T) {
    62  	var numbers = []int64{
    63  		1, 0, -1,
    64  		2, -2,
    65  		1<<63 - 1, -1 << 63,
    66  	}
    67  	coverage := map[flagConstant]bool{}
    68  	for _, x := range numbers {
    69  		for _, y := range numbers {
    70  			a := logicFlags64(x & y)
    71  			b := flagRegister2flagConstant(asmAndFlags(x, y), false)
    72  			if a != b {
    73  				t.Errorf("asmAnd diff: x=%x y=%x got=%s want=%s\n", x, y, a, b)
    74  			}
    75  			coverage[a] = true
    76  		}
    77  	}
    78  	if len(coverage) != 3 {
    79  		t.Errorf("coverage too small, got %d want 3", len(coverage))
    80  	}
    81  }
    82  
    83  func asmAddFlags(x, y int64) int
    84  func asmSubFlags(x, y int64) int
    85  func asmAndFlags(x, y int64) int
    86  
    87  func flagRegister2flagConstant(x int, sub bool) flagConstant {
    88  	var fcb flagConstantBuilder
    89  	switch runtime.GOARCH {
    90  	case "amd64":
    91  		fcb.Z = x>>6&1 != 0
    92  		fcb.N = x>>7&1 != 0
    93  		fcb.C = x>>0&1 != 0
    94  		if sub {
    95  			// Convert from amd64-sense to arm-sense
    96  			fcb.C = !fcb.C
    97  		}
    98  		fcb.V = x>>11&1 != 0
    99  	case "arm64":
   100  		fcb.Z = x>>30&1 != 0
   101  		fcb.N = x>>31&1 != 0
   102  		fcb.C = x>>29&1 != 0
   103  		fcb.V = x>>28&1 != 0
   104  	default:
   105  		panic("unsupported architecture: " + runtime.GOARCH)
   106  	}
   107  	return fcb.encode()
   108  }
   109
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