examples/complex: and bugfixes

examples/sum/sum.s

@@ -4,15 +4,15 @@
 // func Sum(xs []uint64) uint64
 TEXT ·Sum(SB),0,$0-32
 	MOVQ	xs_base(FP), DX
-	MOVQ	xs_len+8(FP), CX
-	XORQ	AX, AX
+	MOVQ	xs_len+8(FP), AX
+	XORQ	CX, CX
 loop:
-	CMPQ	CX, $0x0
+	CMPQ	AX, $0x0
 	JE	done
-	ADDQ	(DX), AX
+	ADDQ	(DX), CX
 	ADDQ	$0x8, DX
-	DECQ	CX
+	DECQ	AX
 	JMP	loop
 done:
-	MOVQ	AX, ret+24(FP)
+	MOVQ	CX, ret+24(FP)
 	RET	

examples/sum/sum_test.go

@@ -7,14 +7,15 @@ import (
 
 //go:generate go run asm.go -out sum.s -stubs stub.go
 
-func expect(xs []uint64) uint64 {
-	var s uint64
-	for _, x := range xs {
-		s += x
-	}
-	return s
-}
-
 func TestSum(t *testing.T) {
-	quick.CheckEqual(Sum, expect, nil)
+	expect := func(xs []uint64) uint64 {
+		var s uint64
+		for _, x := range xs {
+			s += x
+		}
+		return s
+	}
+	if err := quick.CheckEqual(Sum, expect, nil); err != nil {
+		t.Fatal(err)
+	}
 }