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Add direct-relative assembly mnemonics with a numeric displacement. #22

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93c7706
Add new assembly mnemonics for direct-relative addressing mode.
moleus Jun 22, 2022
fe0e7aa
Cover with tests conversions of assembly to instructions for all addr…
moleus Jun 22, 2022
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1 change: 1 addition & 0 deletions bcomp-assembler/src/main/antlr4/ru.ifmo.cs.bcomp.grammar/BCompNG.g4
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Original file line number Diff line number Diff line change
Expand Up @@ -101,6 +101,7 @@ displacementSP

directRelative
: label
| '(' ip '+' number ')'
;

directLoad
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1 change: 1 addition & 0 deletions bcomp-assembler/src/main/java/ru/ifmo/cs/bcomp/assembler/AddressingMode.java
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Expand Up @@ -41,6 +41,7 @@ public String toString() {
s="&undef"; break;
case DIRECT_RELATIVE:
if (reference != null ) {s = reference; break;}
if (number != MemoryWord.UNDEFINED ) {s = "(ip+" + number + ")"; break;}
s="undef"; break;
case DIRECT_LOAD:
if (number != MemoryWord.UNDEFINED ) {s = "#"+number; break;}
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58 changes: 42 additions & 16 deletions bcomp-assembler/src/main/java/ru/ifmo/cs/bcomp/assembler/AsmNg.java
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Expand Up @@ -598,7 +598,7 @@ private AddressingMode addressingModeByParserContext(OperandContext octx) {
break;
case BCompNGParser.RULE_directRelative:
am.addressation = AddressingMode.AddressingType.DIRECT_RELATIVE;
am.reference = referenceByLabelContext(octx.directRelative().label());
setNumberOrReferenceTo(am, octx.directRelative().number(), octx.directRelative().label());
break;
case BCompNGParser.RULE_directLoad:
am.addressation = AddressingMode.AddressingType.DIRECT_LOAD;
Expand All @@ -611,6 +611,15 @@ private AddressingMode addressingModeByParserContext(OperandContext octx) {
return am;
}

private void setNumberOrReferenceTo(AddressingMode am, NumberContext number, LabelContext label) {
if (number != null) {
am.number = parseIntFromNumberContext(number, parser);
}
if (label != null) {
am.reference = referenceByLabelContext(label);
}
}

private String referenceByLabelContext(LabelContext lctx) {
if (lctx == null) {
AssemblerException ae = new AssemblerException("Internal error: LabelContex cant be null here",parser);
Expand All @@ -633,7 +642,7 @@ private void compileOperand(InstructionWord iw) {
if (iw.operand.reference != null) {
Label l = labels.get(iw.operand.reference);
if (l == null) {
reportError(new AssemblerException("Second pass: label refference "+iw.operand.reference+" not found",parser));
reportError(new AssemblerException("Second pass: label reference "+iw.operand.reference+" not found", parser));
}
else {
num = l.address;
Expand All @@ -655,25 +664,16 @@ private void compileOperand(InstructionWord iw) {
iw.value = iw.instruction.opcode | 0x0B00 | convertReferenceToDisplacement(iw);
break;
case DISPLACEMENT_SP:
if (iw.operand.number != MemoryWord.UNDEFINED) {
num = iw.operand.number;
} else {
reportError(new AssemblerException("Second pass: number shoud present in command",parser));
}
if (num > 127 || num < -128) {
reportError(new AssemblerException("Second pass: number exceed limits [-127..128]",parser));
}
num = getOperandNumber(iw);
checkLimits(num, -128, 127);
iw.value = iw.instruction.opcode | 0x0C00 | (num & 0xFF);
break;
case DIRECT_RELATIVE:
iw.value = iw.instruction.opcode | 0x0E00 | convertReferenceToDisplacement(iw);
num = getDisplacement(iw);
iw.value = iw.instruction.opcode | 0x0E00 | (num & 0xFF);
break;
case DIRECT_LOAD:
if (iw.operand.number != MemoryWord.UNDEFINED) {
num = iw.operand.number;
} else {
reportError(new AssemblerException("Second pass: number shoud present in command",parser));
}
num = getOperandNumber(iw);
if (num > 255 || num < -128) {
//TODO error number exceed limit values
throw new AssemblerException(parser);
Expand All @@ -686,6 +686,32 @@ private void compileOperand(InstructionWord iw) {
}
}

/**
* Instruction's operand can be either a reference or a numeric displacement value.
*/
private int getDisplacement(InstructionWord iw) {
if (iw.operand.reference != null) {
return convertReferenceToDisplacement(iw);
}
int number = getOperandNumber(iw);
checkLimits(number, -128, 127);
return number;
}

private void checkLimits(int number, int lowerBound, int upperBound) {
if (number > upperBound || number < lowerBound) {
reportError(new AssemblerException("Second pass: number exceed limits [-128..127]", parser));
}
}

private int getOperandNumber(InstructionWord iw) {
int value = iw.operand.number;
if (value == MemoryWord.UNDEFINED) {
reportError(new AssemblerException("Second pass: number should present in command", parser));
}
return value;
}

private int convertReferenceToDisplacement(InstructionWord iw) {
int num = MemoryWord.UNDEFINED;
String reference = null;
Expand Down
108 changes: 108 additions & 0 deletions bcomp-assembler/src/test/java/ru/ifmo/cs/bcomp/assembler/AsmNgTest.java
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Original file line number Diff line number Diff line change
@@ -0,0 +1,108 @@
package ru.ifmo.cs.bcomp.assembler;

import org.junit.Test;

import java.util.Collection;
import java.util.Collections;
import java.util.Map;
import java.util.stream.Collectors;

import static org.junit.Assert.*;

public class AsmNgTest {
@Test
public void directAbsoluteAddressingMode() {
validateConversion("JUMP 0x5", "C005");
validateConversion("SAME: ADD $SAME", "4000");

assertHasErrors("LD -10");
assertHasErrors("LD 0x800");
assertHasErrors("LD $UNDEFINED");
}

@Test
public void indirectAddressingMode() {
validateConversion("SAME: ADD (SAME)", "48FF");

assertHasErrors("LD (10)");
assertHasErrors("LD $UNDEFINED");
}

@Test
public void postIncrementAddressingMode() {
validateConversion("SAME: ADD (SAME)+", "4AFF");

assertHasErrors("LD (10)+");
assertHasErrors("LD (UNDEFINED)+");
}

@Test
public void preDecrementAddressingMode() {
validateConversion("SAME: ADD -(SAME)", "4BFF");

assertHasErrors("LD -(10)");
assertHasErrors("LD -(UNDEFINED)");
}

@Test
public void displacementSPAddressingMode() {
validateConversion("LD (Sp+-0x5)", "ACFB");
validateConversion("LD &0xF", "AC0F");

assertHasErrors("LD (sp+128)");
assertHasErrors("LD &UNDEFINED");
}

@Test
public void directRelativeAddressingMode() {
validateConversion("JUMP (ip+5)", "CE05");
validateConversion("SAME: ADD SAME", "4EFF");
validateConversion("LD (ip+-2)", "AEFE");

assertHasErrors("LD (ip+-129)");
assertHasErrors("LD (ip+128)");
assertHasErrors("LD UNDEFINED");
}

@Test
public void directLoadAddressingMode() {
validateConversion("LD #0x10", "AF10");
validateConversion("LD #0xFF", "AFFF");

assertHasErrors("LD #256");
assertHasErrors("LD #-129");
assertHasErrors("LD #UNDEFINED");
}

private static void validateConversion(String assembly, String instruction) {
validateProgram(Collections.singletonMap(assembly, instruction));
}

private static void validateProgram(Map<String, String> assemblyToInstruction) {
AsmNg sourceCode = getAssemblySource(assemblyToInstruction.keySet());
Program program = sourceCode.compile();
assertNotNull(program);
assertEquals("Errors occurred while compiling [" + assemblyToInstruction.keySet() + "]", Collections.EMPTY_LIST, sourceCode.getErrors());
String[] correctInstructions = assemblyToInstruction.values().toArray(new String[]{});

for (int i = 0; i < program.binary.size(); i++) {
String actual = getHexInstruction(program.binary.get(i));
String expected = correctInstructions[i];
assertEquals(expected, actual);
}
}

private static void assertHasErrors(String assembly) {
AsmNg sourceCode = getAssemblySource(Collections.singleton(assembly));
sourceCode.compile();
assertNotEquals("No errors occurred while compiling [" + assembly + "]", Collections.EMPTY_LIST, sourceCode.getErrors());
}

private static AsmNg getAssemblySource(Collection<String> assembly) {
return new AsmNg(assembly.stream().collect(Collectors.joining("\n", "ORG 0\nSTART: \n", "")));
}

private static String getHexInstruction(int value) {
return Integer.toHexString(value).toUpperCase();
}
}