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Commit 18050000 authored by Bernie Innocenti's avatar Bernie Innocenti
Browse files

apf: Add immediate encoding tests for LI 

This tests that ApfGenerator knows how to optimally encode positive and
negative immediates of various sizes.

Equivalent tests will follow for LDDW and STDW.

Change-Id: Ia904aecb155c78569e3cf32a2431570281570481
Bug: 73804303
Test: runtest tests/net/java/android/net/apf/ApfTest.java
parent 545d9367

tests/net/java/android/net/apf/ApfTest.java

+71 −4
Original line number Diff line number Diff line
@@ -150,6 +150,15 @@ public class ApfTest { 
        assertVerdict(DROP, program, packet);

    }



    private void assertProgramEquals(byte[] expected, byte[] program) throws AssertionError {

        // assertArrayEquals() would only print one byte, making debugging difficult.

        if (!java.util.Arrays.equals(expected, program)) {

            throw new AssertionError(

                    "\nexpected: " + HexDump.toHexString(expected) +

                    "\nactual:   " + HexDump.toHexString(program));

        }

    }



    private void assertDataMemoryContents(

            int expected, byte[] program, byte[] packet, byte[] data, byte[] expected_data)

            throws IllegalInstructionException, Exception {
@@ -158,7 +167,7 @@ public class ApfTest { 
        // assertArrayEquals() would only print one byte, making debugging difficult.

        if (!java.util.Arrays.equals(expected_data, data)) {

            throw new Exception(

                    "program: " + HexDump.toHexString(program) +

                    "\nprogram:     " + HexDump.toHexString(program) +

                    "\ndata memory: " + HexDump.toHexString(data) +

                    "\nexpected:    " + HexDump.toHexString(expected_data));

        }
@@ -622,6 +631,64 @@ public class ApfTest { 
        }

    }



    /**

     * Test that the generator emits immediates using the shortest possible encoding.

     */

    @Test

    public void testImmediateEncoding() throws IllegalInstructionException {

        final int LI_OPCODE = 13 << 3;

        ApfGenerator gen;



        // 0-byte immediate: li R0, 0

        gen = new ApfGenerator(3);

        gen.addLoadImmediate(Register.R0, 0);

        assertProgramEquals(new byte[]{LI_OPCODE | (0 << 1)}, gen.generate());



        // 1-byte immediate: li R0, 42

        gen = new ApfGenerator(3);

        gen.addLoadImmediate(Register.R0, 42);

        assertProgramEquals(new byte[]{LI_OPCODE | (1 << 1), 42}, gen.generate());



        // 2-byte immediate: li R1, 0x1234

        gen = new ApfGenerator(3);

        gen.addLoadImmediate(Register.R1, 0x1234);

        assertProgramEquals(new byte[]{LI_OPCODE | (2 << 1) | 1 , 0x12, 0x34}, gen.generate());



        // 4-byte immediate: li R0, 0x12345678

        gen = new ApfGenerator(3);

        gen.addLoadImmediate(Register.R0, 0x12345678);

        assertProgramEquals(

                new byte[]{LI_OPCODE | (3 << 1), 0x12, 0x34, 0x56, 0x78},

                gen.generate());

    }



    /**

     * Test that the generator emits negative immediates using the shortest possible encoding.

     */

    @Test

    public void testNegativeImmediateEncoding() throws IllegalInstructionException {

        final int LI_OPCODE = 13 << 3;

        ApfGenerator gen;



        // 1-byte negative immediate: li R0, -42

        gen = new ApfGenerator(3);

        gen.addLoadImmediate(Register.R0, -42);

        assertProgramEquals(new byte[]{LI_OPCODE | (1 << 1), -42}, gen.generate());



        // 2-byte negative immediate: li R1, -0x1234

        gen = new ApfGenerator(3);

        gen.addLoadImmediate(Register.R1, -0x1122);

        assertProgramEquals(new byte[]{LI_OPCODE | (2 << 1) | 1, (byte)0xEE, (byte)0xDE},

                gen.generate());



        // 4-byte negative immediate: li R0, -0x11223344

        gen = new ApfGenerator(3);

        gen.addLoadImmediate(Register.R0, -0x11223344);

        assertProgramEquals(

                new byte[]{LI_OPCODE | (3 << 1), (byte)0xEE, (byte)0xDD, (byte)0xCC, (byte)0xBC},

                gen.generate());

    }



    @Test

    public void testApfDataWrite() throws IllegalInstructionException, Exception {

        byte[] packet = new byte[MIN_PKT_SIZE];