asm: rename XAdd to StoreXAdd

XAdd is just another mode of the Store class, so keep the
naming consistent.

asm/load_store.go

@@ -170,15 +170,15 @@ func StoreImm(dst Register, offset int16, value int64, size Size) Instruction {
 	}
 }
 
-// XAddOp returns the OpCode to atomically add a register to a value in memory.
-func XAddOp(size Size) OpCode {
+// StoreXAddOp returns the OpCode to atomically add a register to a value in memory.
+func StoreXAddOp(size Size) OpCode {
 	return OpCode(StXClass).SetMode(XAddMode).SetSize(size)
 }
 
-// XAdd atomically adds src to *dst.
-func XAdd(dst, src Register, size Size) Instruction {
+// StoreXAdd atomically adds src to *dst.
+func StoreXAdd(dst, src Register, size Size) Instruction {
 	return Instruction{
-		OpCode: XAddOp(size),
+		OpCode: StoreXAddOp(size),
 		Dst:    dst,
 		Src:    src,
 	}

example_sock_extract_dist_test.go

@@ -123,7 +123,7 @@ func newDistanceFilter() (*ebpf.Program, *ebpf.Map, error) {
 		// load ok? inc. Otherwise? jmp to mapupdate
 		asm.JEq.Imm(asm.R0, 0, "update-map"),
 		asm.Mov.Imm(asm.R1, 1),
-		asm.XAdd(asm.R0, asm.R1, asm.DWord),
+		asm.StoreXAdd(asm.R0, asm.R1, asm.DWord),
 		asm.Ja.Label("exit"),
 
 		// MapUpdate